Abstract

INTRODUCTION

Biotechnology can be found in many everyday products: biofuels, vaccines, drugs, cereals, wine, dairy products, and others. The animal world also participates in this technology, with the generation of cloned organisms, chosen for their productive and reproductive characteristics, and consumption of genetically modified (GM) grains (corn and soya, among others) all over the world.¹³13 Corti Varela J. Organismos genéticamente modificados y riesgos sanitarios y medioambientales: derecho de la Unión Europea y de la Organización Mundial del Comercio. Madrid: Ediciones Reus; 2010. ^{, 16}16 De Sebastián L. Un planeta de gordos y hambrientos: la industria alimentaria al desnudo. Barcelona: Editorial Ariel; 2009. ^{, 17}17 Fabbri F. La vida y su manipulación por el hombre. Madrid: Editorial San Pablo; 2005. ^{, 22}22 Houdebine LM. Los transgénicos: verdades y mentiras sobre los organismos genéticamente modificados. Barcelona: Editorial Salvat; 2001. ^{, 27}27 Lambrecht B. La guerra de los cultivos transgénicos: ¿quién decidirá lo que comamos a partir de ahora y qué consecuencias tendrá para mí y para mis hijos? Barcelona: RBA Libros; 2003. ^{, 35}35 Mendiola I. El jardín biotecnológico: tecnociencia, transgénicos y biopolítica. Madrid: Los Libros de la Catarata; 2006. ^{, 38}38 Mir Puigpelat O. Transgénicos y derecho: la nueva regulación de los organismos modificados genéticamente. Madrid: Thomson Civitas; 2004. (Monografías Civitas). ^{, 42}42 Nottingham S. Come tus genes: cómo los alimentos transgénicos entran en nuestra dieta. Barcelona: Paidós Ibérica; 2004. ^{, 44}44 Novás A. El hambre en el mundo y los alimentos transgénicos. Madrid: Los Libros de la Catarata; 2005. ^{, 45}45 Pedauyé Ruiz JJ, Ferro Rodriguez A, Pedauyé Ruiz V. Alimentos transgénicos: la nueva revolución verde. Barcelona: Editorial Mc Graw-Hill/ Interamericana de España; 2000. ^{, 48}48 Rees A. Alimentos modificados genéticamente: una guía breve para personas confundidas. Barcelona: Intermón Oxfam; 2008.

49 Riechmann J. Argumentos recombinantes: sobre cultivos y alimentos transgénicos. Madrid: Los Libros de la Catarata; 1999.

50 Riechmann J. Cultivos y alimentos transgénicos. Madrid: Los Libros de la Catarata; 2000. ^{- 51}51 Riechmann J. Transgénicos, el haz y el envés: una perspectiva crítica. Madrid: Los Libros de la Catarata; 2004. ^{, 54}54 Smith JM. Semillas peligrosas: las mentiras de la industria y los gobiernos sobre lo que comemos. Barcelona: Terapias Verdes; 2004. (Colección Contrapunto). ^{, 57}57 Tamames R. Los transgénicos, conózcalos a fondo. Barcelona: Editorial Ariel; 2003. ^{, 62}62 Villalobos VM, Villalobos A VM. Los transgénicos: oportunidades y amenazas. México (DF): Ediciones Mundi-Prensa; 2008. It is difficult not to encounter or consume transgenic products in the market, whether we are aware of this or not. The introduction of all these advances in genetic engineering has been accompanied by the corresponding patents.¹³13 Corti Varela J. Organismos genéticamente modificados y riesgos sanitarios y medioambientales: derecho de la Unión Europea y de la Organización Mundial del Comercio. Madrid: Ediciones Reus; 2010. ^{, 1}1 Abdulkadri AO, Pinnock S, Tennant PF. Public perception of genetic engineering and the choice to purchase genetically modified food in Jamaica. J Food Agric Environ. 2007;5(2):8-12. ⁶6 Bett C, Ouma JO, De Groote H. Perspectives of gatekeepers in the Kenyan food industry towards genetically modified food. Food Policy. 2010;35(4):332-40. DOI:10.1016/j.foodpol.2010.01.003
https://doi.org/10.1016/j.foodpol.2010.0... ^{, 17}17 Fabbri F. La vida y su manipulación por el hombre. Madrid: Editorial San Pablo; 2005. ^{, 22}22 Houdebine LM. Los transgénicos: verdades y mentiras sobre los organismos genéticamente modificados. Barcelona: Editorial Salvat; 2001. ^{, 27}27 Lambrecht B. La guerra de los cultivos transgénicos: ¿quién decidirá lo que comamos a partir de ahora y qué consecuencias tendrá para mí y para mis hijos? Barcelona: RBA Libros; 2003. ^{, 35}35 Mendiola I. El jardín biotecnológico: tecnociencia, transgénicos y biopolítica. Madrid: Los Libros de la Catarata; 2006. ^{, 38}38 Mir Puigpelat O. Transgénicos y derecho: la nueva regulación de los organismos modificados genéticamente. Madrid: Thomson Civitas; 2004. (Monografías Civitas). ^{, 42}42 Nottingham S. Come tus genes: cómo los alimentos transgénicos entran en nuestra dieta. Barcelona: Paidós Ibérica; 2004. ^{, 44}44 Novás A. El hambre en el mundo y los alimentos transgénicos. Madrid: Los Libros de la Catarata; 2005. ^{, 45}45 Pedauyé Ruiz JJ, Ferro Rodriguez A, Pedauyé Ruiz V. Alimentos transgénicos: la nueva revolución verde. Barcelona: Editorial Mc Graw-Hill/ Interamericana de España; 2000. ^{, 48}48 Rees A. Alimentos modificados genéticamente: una guía breve para personas confundidas. Barcelona: Intermón Oxfam; 2008.

49 Riechmann J. Argumentos recombinantes: sobre cultivos y alimentos transgénicos. Madrid: Los Libros de la Catarata; 1999.

50 Riechmann J. Cultivos y alimentos transgénicos. Madrid: Los Libros de la Catarata; 2000. ^{- 51}51 Riechmann J. Transgénicos, el haz y el envés: una perspectiva crítica. Madrid: Los Libros de la Catarata; 2004. ^{, 54}54 Smith JM. Semillas peligrosas: las mentiras de la industria y los gobiernos sobre lo que comemos. Barcelona: Terapias Verdes; 2004. (Colección Contrapunto). ^{, 57}57 Tamames R. Los transgénicos, conózcalos a fondo. Barcelona: Editorial Ariel; 2003. ^{, 62}62 Villalobos VM, Villalobos A VM. Los transgénicos: oportunidades y amenazas. México (DF): Ediciones Mundi-Prensa; 2008. However, it may be that the promises of GM technology (farming in extreme conditions, increasing nutritional value, sustained increase in harvests, decreasing need for pesticides, reducing world hunger, among others) exist more in the minds of GM supporters than in the commercial supply.¹³13 Corti Varela J. Organismos genéticamente modificados y riesgos sanitarios y medioambientales: derecho de la Unión Europea y de la Organización Mundial del Comercio. Madrid: Ediciones Reus; 2010. ^{, 16}16 De Sebastián L. Un planeta de gordos y hambrientos: la industria alimentaria al desnudo. Barcelona: Editorial Ariel; 2009. ^{, 22}22 Houdebine LM. Los transgénicos: verdades y mentiras sobre los organismos genéticamente modificados. Barcelona: Editorial Salvat; 2001. ^{, 27}27 Lambrecht B. La guerra de los cultivos transgénicos: ¿quién decidirá lo que comamos a partir de ahora y qué consecuencias tendrá para mí y para mis hijos? Barcelona: RBA Libros; 2003. ^{, 35}35 Mendiola I. El jardín biotecnológico: tecnociencia, transgénicos y biopolítica. Madrid: Los Libros de la Catarata; 2006. ^{, 38}38 Mir Puigpelat O. Transgénicos y derecho: la nueva regulación de los organismos modificados genéticamente. Madrid: Thomson Civitas; 2004. (Monografías Civitas). ^{, 42}42 Nottingham S. Come tus genes: cómo los alimentos transgénicos entran en nuestra dieta. Barcelona: Paidós Ibérica; 2004. ^{, 44}44 Novás A. El hambre en el mundo y los alimentos transgénicos. Madrid: Los Libros de la Catarata; 2005. ^{, 45}45 Pedauyé Ruiz JJ, Ferro Rodriguez A, Pedauyé Ruiz V. Alimentos transgénicos: la nueva revolución verde. Barcelona: Editorial Mc Graw-Hill/ Interamericana de España; 2000. ^{, 48}48 Rees A. Alimentos modificados genéticamente: una guía breve para personas confundidas. Barcelona: Intermón Oxfam; 2008.

49 Riechmann J. Argumentos recombinantes: sobre cultivos y alimentos transgénicos. Madrid: Los Libros de la Catarata; 1999.

50 Riechmann J. Cultivos y alimentos transgénicos. Madrid: Los Libros de la Catarata; 2000. ^{- 51}51 Riechmann J. Transgénicos, el haz y el envés: una perspectiva crítica. Madrid: Los Libros de la Catarata; 2004. ^{, 54}54 Smith JM. Semillas peligrosas: las mentiras de la industria y los gobiernos sobre lo que comemos. Barcelona: Terapias Verdes; 2004. (Colección Contrapunto).

Opinions and decisions on GM are divided: they have come to be consumed and accepted in the United States over the last decade, as well as in the rest of America, Australia and South Africa. However, Europe is, partly, resisting the introduction of GM foods into shopping lists.¹⁶16 De Sebastián L. Un planeta de gordos y hambrientos: la industria alimentaria al desnudo. Barcelona: Editorial Ariel; 2009. ^{, 27}27 Lambrecht B. La guerra de los cultivos transgénicos: ¿quién decidirá lo que comamos a partir de ahora y qué consecuencias tendrá para mí y para mis hijos? Barcelona: RBA Libros; 2003. ^{, 42}42 Nottingham S. Come tus genes: cómo los alimentos transgénicos entran en nuestra dieta. Barcelona: Paidós Ibérica; 2004. ^{, 45}45 Pedauyé Ruiz JJ, Ferro Rodriguez A, Pedauyé Ruiz V. Alimentos transgénicos: la nueva revolución verde. Barcelona: Editorial Mc Graw-Hill/ Interamericana de España; 2000. The citizen should be informed about the options available in the market by product labeling.¹³13 Corti Varela J. Organismos genéticamente modificados y riesgos sanitarios y medioambientales: derecho de la Unión Europea y de la Organización Mundial del Comercio. Madrid: Ediciones Reus; 2010. ^{, 16}16 De Sebastián L. Un planeta de gordos y hambrientos: la industria alimentaria al desnudo. Barcelona: Editorial Ariel; 2009. ^{, 38}38 Mir Puigpelat O. Transgénicos y derecho: la nueva regulación de los organismos modificados genéticamente. Madrid: Thomson Civitas; 2004. (Monografías Civitas). ^{, 45}45 Pedauyé Ruiz JJ, Ferro Rodriguez A, Pedauyé Ruiz V. Alimentos transgénicos: la nueva revolución verde. Barcelona: Editorial Mc Graw-Hill/ Interamericana de España; 2000.

In the united States, GM foods are allowed to be sold without being identified as such on the labeling and, in Europe, it is also not necessary if the GM content in the total product is < 0.9%.^aa Regulation (EC) no. 1830/2003 of the European Parliament and Council of 22 September 2003 concerning the traceability and labeling of genetically modified organisms and the traceability of food and feed products produced from GMOs, and the Directive 2001/18/EC. EU Official Journal, no. L 268, 18 October 2003. Correct labeling should be viewed not only as a consumers right, but also as an important way of controlling and providing information on the risk of consuming the product.¹³13 Corti Varela J. Organismos genéticamente modificados y riesgos sanitarios y medioambientales: derecho de la Unión Europea y de la Organización Mundial del Comercio. Madrid: Ediciones Reus; 2010. ^{, 16}16 De Sebastián L. Un planeta de gordos y hambrientos: la industria alimentaria al desnudo. Barcelona: Editorial Ariel; 2009. ^{, 38}38 Mir Puigpelat O. Transgénicos y derecho: la nueva regulación de los organismos modificados genéticamente. Madrid: Thomson Civitas; 2004. (Monografías Civitas). ^{, 45}45 Pedauyé Ruiz JJ, Ferro Rodriguez A, Pedauyé Ruiz V. Alimentos transgénicos: la nueva revolución verde. Barcelona: Editorial Mc Graw-Hill/ Interamericana de España; 2000. It is easier to conduct epidemiological studies to detect any increases in illness of allergies due to consumption of GM food, and other food, if they are correctly labelled.⁴⁵45 Pedauyé Ruiz JJ, Ferro Rodriguez A, Pedauyé Ruiz V. Alimentos transgénicos: la nueva revolución verde. Barcelona: Editorial Mc Graw-Hill/ Interamericana de España; 2000. Tracing has been proven to be an effective tool in appropriate control of the source of food,^bb Regulation (EC) no. 852/2004 of the European Parliament and Council on the hygiene of foodstuffs. EU Official Journal, no. L 139, 29 April 2004. ^{, c}c Corrigendum to Regulation (EC) no. 852/2004 of European Parliament and Council of 29 April 2004 on the hygiene of foodstuffs. EU Official Journal, no. L 226, 25 June 2004. s has been shown in cases of food poisoning.

The objective of this study was to analyze users’ opinions of genetically modified foods and of the information on the label.

METHODS

A critical and systematic analysis was made of studies found in a bibliographical review of the scientific literature.

The data used were obtained by direct and internet consultation of the scientific literature from the following databases: Medline, via PubMed; EMBASE; Web of Knowledge, Institute for Scientific Information (ISI); The Cochrane Library Plus; Food Science and Technology Abstracts (FSTA); Latin American and Caribbean Health Sciences Literature (LILACS); The Cumulative Index to Nursing and Allied Health Literature (CINAHL); AGRICOLA.

Articles which had been published in Spanish, English and Portuguese, in various countries and by different institutions or individual investigators were collected for the entire period for which each primary source had an index.

Medical Subject Headings (MeSH), developed by the National Library of Medicine, were used to search for the documents. Subheadings were not used, nor was it necessary to use tags. Using the Thesaurus, the following descriptors were deemed adequate «organisms, genetically modified» and «food labeling», using these as the major topic in such databases as allowed this (Medline and EMBASE). This guaranteed the greatest search sensitivity and, therefore, the achievement of the most relevant and pertinent articles, eliminating ‘noise’ (articles not related to the principal topic of the search) from the results. The filter (limit): Humans, was used.

The search equation was developed for use in the Medline, via PubMed database, using Boolean connectors, and later adapted to the other databases mentioned above.

The search range was from the first available date, according to the characteristics of each database, until June 2012 (the time of the most recent update).

As a secondary search, to reduce potential publication bias, the bibliography of each article selected in the principal search was examined, aiming to identify studies that had not been detected in the review.

The final selection of articles was conducted according to their fulfilling the following inclusion criteria: having undergone peer review, being relevant, the entire text being available and being written in English, Spanish or Portuguese.

Exclusion criteria were: not containing information on the label, not having been studied in a population and the label not containing information on GM organisms and their products, despite being food products.

The articles were independently evaluated by two of the authors of this review (S-P and S-V) to determine relevance. The STrengthening the Reporting of OBservational studies in Epidemiology (STROBE)^dd STROBE Statement: collaborative initiative of epidemiologists, methodologists, statisticians, researchers and journal editors involved in the conduct and dissemination of observational studies[cited 2014 Feb 8]. Available from: http://www.strobe-statement.org/ questionnaire was used as an aid in evaluating the quality of the articles. The score for agreement between these authors (Kappa index) had to be > 0.80 (very strong agreement) to make selection of the articles for the review valid. As long as they met this criterion, possible disagreements were resolved by consulting a third author (W-B) and consensus then being achieved between the authors.

The accuracy of the data was monitored using double entry, which enabled errors to be noted and corrected through consulting the original again.

The studies were grouped according to the variable studied, aiming to systemize and facilitate understanding of the results, codifying the following data: authors and year of publication, intervention conducted, study population, location, year in which it took place and the main conclusions drawn.

None of the articles were rejected for methodological reasons. There were no restrictions concerning gender or age of the patients or type of sample.

RESULTS

A total of 495 articles were found, of which 372 (75.1%) were from the Institute for Scientific Information (ISI) database, 62 from Web Of Knowledge, (12.3%), from Medline, 31 (6.3%), and 16 from EMBASE (3.2%), from CINAHL, 12 (2.4%), from AGRICOLA and 3 (0.6%) from LILACS. Forty articles were selected after applying the inclusion and exclusion criteria¹1 Abdulkadri AO, Pinnock S, Tennant PF. Public perception of genetic engineering and the choice to purchase genetically modified food in Jamaica. J Food Agric Environ. 2007;5(2):8-12.

2 Badrie N, Titre M, Jueanville M, D’Heureux-Calix F. Public awareness and perception of genetically modified/engineered foods in Trinidad, West Indies. Br Food J. 2006;108(3):192-9. DOI:10.1108/00070700610651016
https://doi.org/10.1108/0007070061065101...

3 Bánáti D, Szabó JA. Knowledge and acceptance of genetically modified foodstuffs in Hungary. Acta Biol Szeged. 2006;50(3-4):115-9.

4 Batrinou AM, Spiliotis V, Sakellaris G. Acceptability of genetically modified maize by young people. Br Food J. 2008;110(3):250-9. DOI:10.1108/00070700810858664
https://doi.org/10.1108/0007070081085866...

5 Baumann A, Osman M, Burton M, Lumley S. Understanding Western Australian consumers’ views: acceptance of food produced using gene technology: a case of herbicide tolerant canola (Brassica napus L.). Environ Sci Pollut Res. 2005;12(1):56. DOI:10.1065/espr2005.01.003
https://doi.org/10.1065/espr2005.01.003... ^{- 6}6 Bett C, Ouma JO, De Groote H. Perspectives of gatekeepers in the Kenyan food industry towards genetically modified food. Food Policy. 2010;35(4):332-40. DOI:10.1016/j.foodpol.2010.01.003
https://doi.org/10.1016/j.foodpol.2010.0... ^{, 8}8 Bredahl L. Determinants of consumer attitudes and purchase intentions with regard to genetically modified foods: results of a cross-national survey. Aarhus (Denmark): Centre for Market Surveillance, Research and Strategy for the Food Sector; 2000. (Working Paper, 69).

9 Brown JL, Ping Y. Consumer perception of risk associated with eating genetically engineered soybeans is less in the presence of a perceived consumer benefit. J Am Diet Assoc. 2003;103(2):208-14. DOI:10.1053/jada.2003.50029
https://doi.org/10.1053/jada.2003.50029...

10 Bukenya JO, Wright NR. Determinants of consumer attitudes and purchase intentions with regard to genetically modified tomatoes. Agribusiness. 2007;23(1):117-30. DOI:10.1002/agr.2010
https://doi.org/10.1002/agr.2010...

11 Carlsson F, Frykblom P, Lagerkvist CJ. Consumer benefits of labels and bans on GM foods: choice experiments with Swedish consumers. Am J Agric Econ. 2007;89(1):152-61. DOI:10.1111/j.1467-8276.2007.00969.x
https://doi.org/10.1111/j.1467-8276.2007... ^{- 12}12 Chembezi DM, Chaverest EL, Wheelock G, Sharma GC, Kebede E, Tegegne F. An econometric evaluation of producers’ preferences for mandatory labeling of genetically modified food products. J Food Distrib Res. 2008;39(1):36-44. ^{, 15}15 Dannenberg A, Scatasta S, Sturm B. Mandatory versus voluntary labeling of genetically modified food: evidence from an economic experiment. Agric Econ. 2011;42(3):373-86. DOI:10.1111/j.1574-0862.2010.00520.x
https://doi.org/10.1111/j.1574-0862.2010... ^{, 18}18 Februhartanty J, Widyastuti TN, Iswarawanti DN. Attitudes of agricultural scientists in Indonesia towards genetically modified foods. Asia Pac J Clin Nutr. 2007;16(2):375-80. ^{, 20}20 Gaivoronskaia G, Hvinden B. Consumers with allergic reaction to food: perception of and response to food risk in general and genetically modified food in particular. Sci Technol HumValues. 2006;31(6):702-3. DOI:10.1177/0162243906291867
https://doi.org/10.1177/0162243906291867... ^{, 21}21 Ganiere P, Chern WS, Hahn D. A continuum of consumer attitudes towards genetically modified foods in the US. J Agric Resour Econ. 2006;31(1):129-49. ^{, 23}23 Huffman WE, Rousu M, Shogren JF, Tegene A. The effects of prior beliefs and learning on consumers’ acceptance of genetically modified foods. J Econ Behav Organ. 2007;63(1):193-206. DOI:10.1016/j.jebo.2005.04.019
https://doi.org/10.1016/j.jebo.2005.04.0...

24 Irani T, Sinclair J. The effect of labeling genetically modified food on perceptions of accountability. J Appl Commun. 2004;88(1):29-42.

25 Kim RB. A multi-attribute model of Japanese consumer’s purchase intention for GM foods. Agric Econ Czech. 2010;56(10):449-59. ^{- 26}26 Knight JG, Mather DW, Holdsworth DK. Genetically modified crops and country image of food exporting countries. Br Food J. 2005;107(9):653-62. DOI:10.1108/00070700510615035
https://doi.org/10.1108/0007070051061503... ^{, 28}28 Loureiro ML, Hine S. Preferences and willingness to pay for GM labeling policies. Food Policy. 2004;29(5):467-83. DOI:10.1016/j.foodpol.2004.07.001
https://doi.org/10.1016/j.foodpol.2004.0...

29 Lü L. Chinese public understanding of the use of agricultural biotechnology: a case study from Zhejiang Province of China. J Zhejiang Univ Sci B. 2006;7(4):257-66. DOI:10.1631/jzus.2006.B0257
https://doi.org/10.1631/jzus.2006.B0257...

30 Lusk JL, House LO, Valli C, Jaeger SR, Moore M, Morrow B, et al. Consumer welfare effects of introducing and labeling genetically modified food. Econ Lett. 2005;88(3):382-8. DOI:10.1016/j.econlet.2005.03.009
https://doi.org/10.1016/j.econlet.2005.0...

31 Lusk JL, Rozan A. Public policy and endogenous beliefs: the case of genetically modified food. J Agric Resour Econ. 2008;33(2):270-89.

32 Man-ser J, Tsu-tan F, Huang CL. A conjoint/logit analysis of consumers’ responses to genetically modified tofu in Taiwan. J Agric Econ. 2007;58(2):330-47. DOI:10.1111/j.1477-9552.2007.00100.x
https://doi.org/10.1111/j.1477-9552.2007...

33 Marks L, Kalaitzandonakes NG, Vickner S. Consumer purchasing behaviour towards GM foods in the Netherlands. In: Evenson RE, Santaniello V, editors. Consumer acceptance of genetically modified foods. Wallingford (UK): CABI Publishing; 2004. p.23-39. ^{- 34}34 McGarry-Wolf M, McDonell J, Domegan C, Yount H. Consumer attitudes towards GM food in Ireland and the USA. In: Evenson RE, Santaniello V, editors. Consumer acceptance of genetically modified foods. Wallingford (UK): CABI Publishing; 2004. p.143-54. ^{, 36}36 Miles S, Ueland O, Frewer LJ. Public attitudes towards genetically-modified food. Br Food J. 2005;107(4):246-62. DOI:10.1108/00070700510589521
https://doi.org/10.1108/0007070051058952... ^{, 40}40 Mucci A, Hough G. Perceptions of genetically modified foods by consumers in Argentina. Food Qual Prefer. 2004;15(1):43-51. DOI:10.1016/S0950-3293(03)00021-1.
https://doi.org/10.1016/S0950-3293(03)00... ^{, 41}41 Nayga Jr RM, Fisher MG, Onyangob B. Acceptance of genetically modified food: comparing consumer perspectives in the US and South Korea. Agric Econ. 2006;34(3):331-41. DOI:10.1111/j.1574-0864.2006.00129.x
https://doi.org/10.1111/j.1574-0864.2006... ^{, 43}43 Noussair C, Robin S, Ruffieux B. Do consumers not care about biotech foods or do they just not read the labels? Econ Lett. 2002;75(1):47-53. DOI:10.1016/S0165-1765(01)00594-8
https://doi.org/10.1016/S0165-1765(01)00... ^{, 46}46 Radas S, Teisl MF, Roe B. An open mind wants more: opinion strength and the desire for genetically modified food labeling policy. J Consum Aff. 2008;42(3):335-61. DOI:10.1111/j.1745-6606.2008.00111.x
https://doi.org/10.1111/j.1745-6606.2008... ,⁴⁷47 Ramon D, Diamante A, Calvo MD. Food biotechnology and education. Electron J Biotechnol. 2008;11(5 Spec Iss):1-5. DOI:10.2225/vol11-issue5-fulltext-7
https://doi.org/10.2225/vol11-issue5-ful... , ⁵²52 Scholder EP, Bone PF. Stained by the label? Stigma and the case of genetically modified foods. J Public Policy Mark. 2008;27(1):69-82. DOI:10.1509/jppm.27.1.69
https://doi.org/10.1509/jppm.27.1... ^{, 53}53 Shehata S. Attitudes of Japanese and Hawaiian consumers toward labeling genetically modified fruits. In: Martorell S, Guedes Soares C, Barnett J, editors. Safety, reliability and risk analysis: theory, methods and applications. London: CRC Press/Taylor & Francis Group; 2008. p.2285-8. ^{, 56}56 Subrahmanyan S, Cheng PS. Perceptions and attitudes of Singaporeans towards genetically modified food. J Consum Aff. 2000;34(2):269-90. DOI:10.1111/j.1745-6606.2000.tb00094.x
https://doi.org/10.1111/j.1745-6606.2000... ^{, 58}58 Teisl MF, Halverson L, O’Brien K, Roe B, Ross N, Vayda M. Focus group reactions to genetically modified food labels. AgBioForum. 2002;5(1):6-9.

59 Tenbült P, De Vries N, Dreezens E, Martijn C. Categorizing genetically modified food products: effects of labeling on information processing. Br Food J. 2007;109(4):305-14. DOI:10.1108/00070700710736552
https://doi.org/10.1108/0007070071073655...

60 Todt O, Muñoz E, González M, Ponce G, Estévez B. Consumer attitudes and the governance of food safety. Public Underst Sci. 2009;18(1):103-14. DOI:10.1177/0963662507078019
https://doi.org/10.1177/0963662507078019... ^{- 61}61 Veeman MM, Hu W, Adamowicz WL. Consumers’ preferences for GM food and voluntary information access: a simultaneous choice analysis. Can J Agric Econ. 2009;57(2):241-67. DOI:10.1111/j.1744-7976.2009.01150.x
https://doi.org/10.1111/j.1744-7976.2009... ^{, 63}63 Zhong F, Marchant MA, Ding Y, Lu K. GM Foods: a Nanjing case study of Chinese consumers’ awareness and potential attitudes. AgBioForum. 2002;5(4):136-44. (Figure).

It was not necessary to measure agreement between the authors, as agreement on the studies’ relevance was 100%. All of the selected articles were above the median of the items proposed by STROBE for observational studies.

In addition to redundant articles, appearing in different databases, we also found studies dealing with the same intervention in various publications. In such cases, the most recently published article covering data from the entire intervention was selected.²³23 Huffman WE, Rousu M, Shogren JF, Tegene A. The effects of prior beliefs and learning on consumers’ acceptance of genetically modified foods. J Econ Behav Organ. 2007;63(1):193-206. DOI:10.1016/j.jebo.2005.04.019
https://doi.org/10.1016/j.jebo.2005.04.0... ^{, 46}46 Radas S, Teisl MF, Roe B. An open mind wants more: opinion strength and the desire for genetically modified food labeling policy. J Consum Aff. 2008;42(3):335-61. DOI:10.1111/j.1745-6606.2008.00111.x
https://doi.org/10.1111/j.1745-6606.2008... ^{, 53}53 Shehata S. Attitudes of Japanese and Hawaiian consumers toward labeling genetically modified fruits. In: Martorell S, Guedes Soares C, Barnett J, editors. Safety, reliability and risk analysis: theory, methods and applications. London: CRC Press/Taylor & Francis Group; 2008. p.2285-8. ^{, 61}61 Veeman MM, Hu W, Adamowicz WL. Consumers’ preferences for GM food and voluntary information access: a simultaneous choice analysis. Can J Agric Econ. 2009;57(2):241-67. DOI:10.1111/j.1744-7976.2009.01150.x
https://doi.org/10.1111/j.1744-7976.2009...

In some articles, depending on the study population, various interventions were included. Thus, four interventions in Bredahl,⁸8 Bredahl L. Determinants of consumer attitudes and purchase intentions with regard to genetically modified foods: results of a cross-national survey. Aarhus (Denmark): Centre for Market Surveillance, Research and Strategy for the Food Sector; 2000. (Working Paper, 69). three in Huffman et al,²³23 Huffman WE, Rousu M, Shogren JF, Tegene A. The effects of prior beliefs and learning on consumers’ acceptance of genetically modified foods. J Econ Behav Organ. 2007;63(1):193-206. DOI:10.1016/j.jebo.2005.04.019
https://doi.org/10.1016/j.jebo.2005.04.0... Knight et al²⁶26 Knight JG, Mather DW, Holdsworth DK. Genetically modified crops and country image of food exporting countries. Br Food J. 2005;107(9):653-62. DOI:10.1108/00070700510615035
https://doi.org/10.1108/0007070051061503... y Miles et al,³⁶36 Miles S, Ueland O, Frewer LJ. Public attitudes towards genetically-modified food. Br Food J. 2005;107(4):246-62. DOI:10.1108/00070700510589521
https://doi.org/10.1108/0007070051058952... and two in articles by Brown,⁹9 Brown JL, Ping Y. Consumer perception of risk associated with eating genetically engineered soybeans is less in the presence of a perceived consumer benefit. J Am Diet Assoc. 2003;103(2):208-14. DOI:10.1053/jada.2003.50029
https://doi.org/10.1053/jada.2003.50029... Lü,²⁹29 Lü L. Chinese public understanding of the use of agricultural biotechnology: a case study from Zhejiang Province of China. J Zhejiang Univ Sci B. 2006;7(4):257-66. DOI:10.1631/jzus.2006.B0257
https://doi.org/10.1631/jzus.2006.B0257... McGarry Wolf et al,³⁴34 McGarry-Wolf M, McDonell J, Domegan C, Yount H. Consumer attitudes towards GM food in Ireland and the USA. In: Evenson RE, Santaniello V, editors. Consumer acceptance of genetically modified foods. Wallingford (UK): CABI Publishing; 2004. p.143-54. Nayga et al,⁴¹41 Nayga Jr RM, Fisher MG, Onyangob B. Acceptance of genetically modified food: comparing consumer perspectives in the US and South Korea. Agric Econ. 2006;34(3):331-41. DOI:10.1111/j.1574-0864.2006.00129.x
https://doi.org/10.1111/j.1574-0864.2006... Shehata,⁵³53 Shehata S. Attitudes of Japanese and Hawaiian consumers toward labeling genetically modified fruits. In: Martorell S, Guedes Soares C, Barnett J, editors. Safety, reliability and risk analysis: theory, methods and applications. London: CRC Press/Taylor & Francis Group; 2008. p.2285-8. Tenbült et al,⁵⁹59 Tenbült P, De Vries N, Dreezens E, Martijn C. Categorizing genetically modified food products: effects of labeling on information processing. Br Food J. 2007;109(4):305-14. DOI:10.1108/00070700710736552
https://doi.org/10.1108/0007070071073655... and Zhong et al⁶³63 Zhong F, Marchant MA, Ding Y, Lu K. GM Foods: a Nanjing case study of Chinese consumers’ awareness and potential attitudes. AgBioForum. 2002;5(4):136-44. are considered. The rest of the articles had evidence of one intervention each. In total, there were 56 interventions in the 40 selected articles (Table).

The most used intervention method for obtaining data was the personal interview, 30.3% ²2 Badrie N, Titre M, Jueanville M, D’Heureux-Calix F. Public awareness and perception of genetically modified/engineered foods in Trinidad, West Indies. Br Food J. 2006;108(3):192-9. DOI:10.1108/00070700610651016
https://doi.org/10.1108/0007070061065101... ^{, 4}4 Batrinou AM, Spiliotis V, Sakellaris G. Acceptability of genetically modified maize by young people. Br Food J. 2008;110(3):250-9. DOI:10.1108/00070700810858664
https://doi.org/10.1108/0007070081085866... ^{, 6}6 Bett C, Ouma JO, De Groote H. Perspectives of gatekeepers in the Kenyan food industry towards genetically modified food. Food Policy. 2010;35(4):332-40. DOI:10.1016/j.foodpol.2010.01.003
https://doi.org/10.1016/j.foodpol.2010.0... ^{, 10}10 Bukenya JO, Wright NR. Determinants of consumer attitudes and purchase intentions with regard to genetically modified tomatoes. Agribusiness. 2007;23(1):117-30. DOI:10.1002/agr.2010
https://doi.org/10.1002/agr.2010... ^{, 12}12 Chembezi DM, Chaverest EL, Wheelock G, Sharma GC, Kebede E, Tegegne F. An econometric evaluation of producers’ preferences for mandatory labeling of genetically modified food products. J Food Distrib Res. 2008;39(1):36-44. ^{, 18}18 Februhartanty J, Widyastuti TN, Iswarawanti DN. Attitudes of agricultural scientists in Indonesia towards genetically modified foods. Asia Pac J Clin Nutr. 2007;16(2):375-80. ^{, 24}24 Irani T, Sinclair J. The effect of labeling genetically modified food on perceptions of accountability. J Appl Commun. 2004;88(1):29-42. ^{, 26}26 Knight JG, Mather DW, Holdsworth DK. Genetically modified crops and country image of food exporting countries. Br Food J. 2005;107(9):653-62. DOI:10.1108/00070700510615035
https://doi.org/10.1108/0007070051061503... ^{, 28}28 Loureiro ML, Hine S. Preferences and willingness to pay for GM labeling policies. Food Policy. 2004;29(5):467-83. DOI:10.1016/j.foodpol.2004.07.001
https://doi.org/10.1016/j.foodpol.2004.0... ^{, 29}29 Lü L. Chinese public understanding of the use of agricultural biotechnology: a case study from Zhejiang Province of China. J Zhejiang Univ Sci B. 2006;7(4):257-66. DOI:10.1631/jzus.2006.B0257
https://doi.org/10.1631/jzus.2006.B0257... ,³²32 Man-ser J, Tsu-tan F, Huang CL. A conjoint/logit analysis of consumers’ responses to genetically modified tofu in Taiwan. J Agric Econ. 2007;58(2):330-47. DOI:10.1111/j.1477-9552.2007.00100.x
https://doi.org/10.1111/j.1477-9552.2007... , ³⁴34 McGarry-Wolf M, McDonell J, Domegan C, Yount H. Consumer attitudes towards GM food in Ireland and the USA. In: Evenson RE, Santaniello V, editors. Consumer acceptance of genetically modified foods. Wallingford (UK): CABI Publishing; 2004. p.143-54. ^{, 41}41 Nayga Jr RM, Fisher MG, Onyangob B. Acceptance of genetically modified food: comparing consumer perspectives in the US and South Korea. Agric Econ. 2006;34(3):331-41. DOI:10.1111/j.1574-0864.2006.00129.x
https://doi.org/10.1111/j.1574-0864.2006... ^{, 52}52 Scholder EP, Bone PF. Stained by the label? Stigma and the case of genetically modified foods. J Public Policy Mark. 2008;27(1):69-82. DOI:10.1509/jppm.27.1.69
https://doi.org/10.1509/jppm.27.1... ^{, 53}53 Shehata S. Attitudes of Japanese and Hawaiian consumers toward labeling genetically modified fruits. In: Martorell S, Guedes Soares C, Barnett J, editors. Safety, reliability and risk analysis: theory, methods and applications. London: CRC Press/Taylor & Francis Group; 2008. p.2285-8. of the 56 interventions; followed by group work, 30.3%;⁹9 Brown JL, Ping Y. Consumer perception of risk associated with eating genetically engineered soybeans is less in the presence of a perceived consumer benefit. J Am Diet Assoc. 2003;103(2):208-14. DOI:10.1053/jada.2003.50029
https://doi.org/10.1053/jada.2003.50029... ^{, 15}15 Dannenberg A, Scatasta S, Sturm B. Mandatory versus voluntary labeling of genetically modified food: evidence from an economic experiment. Agric Econ. 2011;42(3):373-86. DOI:10.1111/j.1574-0862.2010.00520.x
https://doi.org/10.1111/j.1574-0862.2010... ,²³23 Huffman WE, Rousu M, Shogren JF, Tegene A. The effects of prior beliefs and learning on consumers’ acceptance of genetically modified foods. J Econ Behav Organ. 2007;63(1):193-206. DOI:10.1016/j.jebo.2005.04.019
https://doi.org/10.1016/j.jebo.2005.04.0... , ²⁹29 Lü L. Chinese public understanding of the use of agricultural biotechnology: a case study from Zhejiang Province of China. J Zhejiang Univ Sci B. 2006;7(4):257-66. DOI:10.1631/jzus.2006.B0257
https://doi.org/10.1631/jzus.2006.B0257... ^{, 30}30 Lusk JL, House LO, Valli C, Jaeger SR, Moore M, Morrow B, et al. Consumer welfare effects of introducing and labeling genetically modified food. Econ Lett. 2005;88(3):382-8. DOI:10.1016/j.econlet.2005.03.009
https://doi.org/10.1016/j.econlet.2005.0... ^{, 40}40 Mucci A, Hough G. Perceptions of genetically modified foods by consumers in Argentina. Food Qual Prefer. 2004;15(1):43-51. DOI:10.1016/S0950-3293(03)00021-1.
https://doi.org/10.1016/S0950-3293(03)00... ^{, 43}43 Noussair C, Robin S, Ruffieux B. Do consumers not care about biotech foods or do they just not read the labels? Econ Lett. 2002;75(1):47-53. DOI:10.1016/S0165-1765(01)00594-8
https://doi.org/10.1016/S0165-1765(01)00... ^{, 58}58 Teisl MF, Halverson L, O’Brien K, Roe B, Ross N, Vayda M. Focus group reactions to genetically modified food labels. AgBioForum. 2002;5(1):6-9. ^{, 59}59 Tenbült P, De Vries N, Dreezens E, Martijn C. Categorizing genetically modified food products: effects of labeling on information processing. Br Food J. 2007;109(4):305-14. DOI:10.1108/00070700710736552
https://doi.org/10.1108/0007070071073655... questionnaires, 12.5%;³3 Bánáti D, Szabó JA. Knowledge and acceptance of genetically modified foodstuffs in Hungary. Acta Biol Szeged. 2006;50(3-4):115-9. ^{, 25}25 Kim RB. A multi-attribute model of Japanese consumer’s purchase intention for GM foods. Agric Econ Czech. 2010;56(10):449-59. ^{, 36}36 Miles S, Ueland O, Frewer LJ. Public attitudes towards genetically-modified food. Br Food J. 2005;107(4):246-62. DOI:10.1108/00070700510589521
https://doi.org/10.1108/0007070051058952... ^{, 47}47 Ramon D, Diamante A, Calvo MD. Food biotechnology and education. Electron J Biotechnol. 2008;11(5 Spec Iss):1-5. DOI:10.2225/vol11-issue5-fulltext-7
https://doi.org/10.2225/vol11-issue5-ful... ^{, 56}56 Subrahmanyan S, Cheng PS. Perceptions and attitudes of Singaporeans towards genetically modified food. J Consum Aff. 2000;34(2):269-90. DOI:10.1111/j.1745-6606.2000.tb00094.x
https://doi.org/10.1111/j.1745-6606.2000... telephone surveys, 12.5%;¹1 Abdulkadri AO, Pinnock S, Tennant PF. Public perception of genetic engineering and the choice to purchase genetically modified food in Jamaica. J Food Agric Environ. 2007;5(2):8-12. ^{, 5}5 Baumann A, Osman M, Burton M, Lumley S. Understanding Western Australian consumers’ views: acceptance of food produced using gene technology: a case of herbicide tolerant canola (Brassica napus L.). Environ Sci Pollut Res. 2005;12(1):56. DOI:10.1065/espr2005.01.003
https://doi.org/10.1065/espr2005.01.003... ^{, 21}21 Ganiere P, Chern WS, Hahn D. A continuum of consumer attitudes towards genetically modified foods in the US. J Agric Resour Econ. 2006;31(1):129-49. ^{, 41}41 Nayga Jr RM, Fisher MG, Onyangob B. Acceptance of genetically modified food: comparing consumer perspectives in the US and South Korea. Agric Econ. 2006;34(3):331-41. DOI:10.1111/j.1574-0864.2006.00129.x
https://doi.org/10.1111/j.1574-0864.2006... ^{, 53}53 Shehata S. Attitudes of Japanese and Hawaiian consumers toward labeling genetically modified fruits. In: Martorell S, Guedes Soares C, Barnett J, editors. Safety, reliability and risk analysis: theory, methods and applications. London: CRC Press/Taylor & Francis Group; 2008. p.2285-8. ^{, 60}60 Todt O, Muñoz E, González M, Ponce G, Estévez B. Consumer attitudes and the governance of food safety. Public Underst Sci. 2009;18(1):103-14. DOI:10.1177/0963662507078019
https://doi.org/10.1177/0963662507078019... ^{, 63}63 Zhong F, Marchant MA, Ding Y, Lu K. GM Foods: a Nanjing case study of Chinese consumers’ awareness and potential attitudes. AgBioForum. 2002;5(4):136-44. mail surveys, 7.1%;¹¹11 Carlsson F, Frykblom P, Lagerkvist CJ. Consumer benefits of labels and bans on GM foods: choice experiments with Swedish consumers. Am J Agric Econ. 2007;89(1):152-61. DOI:10.1111/j.1467-8276.2007.00969.x
https://doi.org/10.1111/j.1467-8276.2007... ^{, 20}20 Gaivoronskaia G, Hvinden B. Consumers with allergic reaction to food: perception of and response to food risk in general and genetically modified food in particular. Sci Technol HumValues. 2006;31(6):702-3. DOI:10.1177/0162243906291867
https://doi.org/10.1177/0162243906291867... ^{, 31}31 Lusk JL, Rozan A. Public policy and endogenous beliefs: the case of genetically modified food. J Agric Resour Econ. 2008;33(2):270-89. ^{, 46}46 Radas S, Teisl MF, Roe B. An open mind wants more: opinion strength and the desire for genetically modified food labeling policy. J Consum Aff. 2008;42(3):335-61. DOI:10.1111/j.1745-6606.2008.00111.x
https://doi.org/10.1111/j.1745-6606.2008... point of sale data, 3.6%;¹³13 Corti Varela J. Organismos genéticamente modificados y riesgos sanitarios y medioambientales: derecho de la Unión Europea y de la Organización Mundial del Comercio. Madrid: Ediciones Reus; 2010. ^{, 16}16 De Sebastián L. Un planeta de gordos y hambrientos: la industria alimentaria al desnudo. Barcelona: Editorial Ariel; 2009. ^{, 26}26 Knight JG, Mather DW, Holdsworth DK. Genetically modified crops and country image of food exporting countries. Br Food J. 2005;107(9):653-62. DOI:10.1108/00070700510615035
https://doi.org/10.1108/0007070051061503... ^{, 33}33 Marks L, Kalaitzandonakes NG, Vickner S. Consumer purchasing behaviour towards GM foods in the Netherlands. In: Evenson RE, Santaniello V, editors. Consumer acceptance of genetically modified foods. Wallingford (UK): CABI Publishing; 2004. p.23-39. ^{, 38}38 Mir Puigpelat O. Transgénicos y derecho: la nueva regulación de los organismos modificados genéticamente. Madrid: Thomson Civitas; 2004. (Monografías Civitas).,⁴⁵45 Pedauyé Ruiz JJ, Ferro Rodriguez A, Pedauyé Ruiz V. Alimentos transgénicos: la nueva revolución verde. Barcelona: Editorial Mc Graw-Hill/ Interamericana de España; 2000. internet survey, 1.8%⁶¹61 Veeman MM, Hu W, Adamowicz WL. Consumers’ preferences for GM food and voluntary information access: a simultaneous choice analysis. Can J Agric Econ. 2009;57(2):241-67. DOI:10.1111/j.1744-7976.2009.01150.x
https://doi.org/10.1111/j.1744-7976.2009... and investigation of journals, 1.8%.⁶³63 Zhong F, Marchant MA, Ding Y, Lu K. GM Foods: a Nanjing case study of Chinese consumers’ awareness and potential attitudes. AgBioForum. 2002;5(4):136-44.

The population investigated provided heterogeneous data, ranging from very concrete data on age, sex and levels of culture and income,¹⁵15 Dannenberg A, Scatasta S, Sturm B. Mandatory versus voluntary labeling of genetically modified food: evidence from an economic experiment. Agric Econ. 2011;42(3):373-86. DOI:10.1111/j.1574-0862.2010.00520.x
https://doi.org/10.1111/j.1574-0862.2010... ^{, 23}23 Huffman WE, Rousu M, Shogren JF, Tegene A. The effects of prior beliefs and learning on consumers’ acceptance of genetically modified foods. J Econ Behav Organ. 2007;63(1):193-206. DOI:10.1016/j.jebo.2005.04.019
https://doi.org/10.1016/j.jebo.2005.04.0... ^{, 41}41 Nayga Jr RM, Fisher MG, Onyangob B. Acceptance of genetically modified food: comparing consumer perspectives in the US and South Korea. Agric Econ. 2006;34(3):331-41. DOI:10.1111/j.1574-0864.2006.00129.x
https://doi.org/10.1111/j.1574-0864.2006... ^{, 52}52 Scholder EP, Bone PF. Stained by the label? Stigma and the case of genetically modified foods. J Public Policy Mark. 2008;27(1):69-82. DOI:10.1509/jppm.27.1.69
https://doi.org/10.1509/jppm.27.1... ^{, 53}53 Shehata S. Attitudes of Japanese and Hawaiian consumers toward labeling genetically modified fruits. In: Martorell S, Guedes Soares C, Barnett J, editors. Safety, reliability and risk analysis: theory, methods and applications. London: CRC Press/Taylor & Francis Group; 2008. p.2285-8. to merely providing data on the number of participants: 12 studies (30.0%).³3 Bánáti D, Szabó JA. Knowledge and acceptance of genetically modified foodstuffs in Hungary. Acta Biol Szeged. 2006;50(3-4):115-9. ^{, 5}5 Baumann A, Osman M, Burton M, Lumley S. Understanding Western Australian consumers’ views: acceptance of food produced using gene technology: a case of herbicide tolerant canola (Brassica napus L.). Environ Sci Pollut Res. 2005;12(1):56. DOI:10.1065/espr2005.01.003
https://doi.org/10.1065/espr2005.01.003... ^{, 10}10 Bukenya JO, Wright NR. Determinants of consumer attitudes and purchase intentions with regard to genetically modified tomatoes. Agribusiness. 2007;23(1):117-30. DOI:10.1002/agr.2010
https://doi.org/10.1002/agr.2010... ^{, 24}24 Irani T, Sinclair J. The effect of labeling genetically modified food on perceptions of accountability. J Appl Commun. 2004;88(1):29-42.

25 Kim RB. A multi-attribute model of Japanese consumer’s purchase intention for GM foods. Agric Econ Czech. 2010;56(10):449-59. ^{- 26}26 Knight JG, Mather DW, Holdsworth DK. Genetically modified crops and country image of food exporting countries. Br Food J. 2005;107(9):653-62. DOI:10.1108/00070700510615035
https://doi.org/10.1108/0007070051061503... ^{, 31}31 Lusk JL, Rozan A. Public policy and endogenous beliefs: the case of genetically modified food. J Agric Resour Econ. 2008;33(2):270-89. ^{,34, 41}41 Nayga Jr RM, Fisher MG, Onyangob B. Acceptance of genetically modified food: comparing consumer perspectives in the US and South Korea. Agric Econ. 2006;34(3):331-41. DOI:10.1111/j.1574-0864.2006.00129.x
https://doi.org/10.1111/j.1574-0864.2006... ^{, 53}53 Shehata S. Attitudes of Japanese and Hawaiian consumers toward labeling genetically modified fruits. In: Martorell S, Guedes Soares C, Barnett J, editors. Safety, reliability and risk analysis: theory, methods and applications. London: CRC Press/Taylor & Francis Group; 2008. p.2285-8. ^{, 61}61 Veeman MM, Hu W, Adamowicz WL. Consumers’ preferences for GM food and voluntary information access: a simultaneous choice analysis. Can J Agric Econ. 2009;57(2):241-67. DOI:10.1111/j.1744-7976.2009.01150.x
https://doi.org/10.1111/j.1744-7976.2009... ^{, 63}63 Zhong F, Marchant MA, Ding Y, Lu K. GM Foods: a Nanjing case study of Chinese consumers’ awareness and potential attitudes. AgBioForum. 2002;5(4):136-44.

The intervention with the largest number of participants⁴⁶46 Radas S, Teisl MF, Roe B. An open mind wants more: opinion strength and the desire for genetically modified food labeling policy. J Consum Aff. 2008;42(3):335-61. DOI:10.1111/j.1745-6606.2008.00111.x
https://doi.org/10.1111/j.1745-6606.2008... was n = 2,387 and that with the lowest number had²⁶26 Knight JG, Mather DW, Holdsworth DK. Genetically modified crops and country image of food exporting countries. Br Food J. 2005;107(9):653-62. DOI:10.1108/00070700510615035
https://doi.org/10.1108/0007070051061503... n = 17. In one of the interventions, it was noted that the population was selected according to sex (only women).³⁰30 Lusk JL, House LO, Valli C, Jaeger SR, Moore M, Morrow B, et al. Consumer welfare effects of introducing and labeling genetically modified food. Econ Lett. 2005;88(3):382-8. DOI:10.1016/j.econlet.2005.03.009
https://doi.org/10.1016/j.econlet.2005.0...

Of the 40 studies selected, 44.6% of interventions took place in Europe, 33.9% in America, 14.3% in Asia, 5.3% in Oceania and 1.8% in Africa. Whereas in Europe, Asia, Africa and Oceania, the interventions were distributed homogeneously (between one and three interventions) in different countries, in America the interventions centered on the USA (15 of the 19 interventions).

The design was cross-sectional, with the exception of monitoring articles published in journals, which lasted six years,⁶³63 Zhong F, Marchant MA, Ding Y, Lu K. GM Foods: a Nanjing case study of Chinese consumers’ awareness and potential attitudes. AgBioForum. 2002;5(4):136-44. and one of the studies which collected point of sale data and lasted four years.³³33 Marks L, Kalaitzandonakes NG, Vickner S. Consumer purchasing behaviour towards GM foods in the Netherlands. In: Evenson RE, Santaniello V, editors. Consumer acceptance of genetically modified foods. Wallingford (UK): CABI Publishing; 2004. p.23-39.

The most recent interventions (four in total) were performed in 2007 (7.1%),⁶6 Bett C, Ouma JO, De Groote H. Perspectives of gatekeepers in the Kenyan food industry towards genetically modified food. Food Policy. 2010;35(4):332-40. DOI:10.1016/j.foodpol.2010.01.003
https://doi.org/10.1016/j.foodpol.2010.0... ^{, 15}15 Dannenberg A, Scatasta S, Sturm B. Mandatory versus voluntary labeling of genetically modified food: evidence from an economic experiment. Agric Econ. 2011;42(3):373-86. DOI:10.1111/j.1574-0862.2010.00520.x
https://doi.org/10.1111/j.1574-0862.2010... ^{, 47}47 Ramon D, Diamante A, Calvo MD. Food biotechnology and education. Electron J Biotechnol. 2008;11(5 Spec Iss):1-5. DOI:10.2225/vol11-issue5-fulltext-7
https://doi.org/10.2225/vol11-issue5-ful... ^{, 53}53 Shehata S. Attitudes of Japanese and Hawaiian consumers toward labeling genetically modified fruits. In: Martorell S, Guedes Soares C, Barnett J, editors. Safety, reliability and risk analysis: theory, methods and applications. London: CRC Press/Taylor & Francis Group; 2008. p.2285-8. in Germany, Kenya, Japan and Spain.

In 45.0% of the 40 selected articles, the population studied were shown to be clearly in favor of mandatory GM product labeling.¹1 Abdulkadri AO, Pinnock S, Tennant PF. Public perception of genetic engineering and the choice to purchase genetically modified food in Jamaica. J Food Agric Environ. 2007;5(2):8-12. ^{, 3}3 Bánáti D, Szabó JA. Knowledge and acceptance of genetically modified foodstuffs in Hungary. Acta Biol Szeged. 2006;50(3-4):115-9.

4 Batrinou AM, Spiliotis V, Sakellaris G. Acceptability of genetically modified maize by young people. Br Food J. 2008;110(3):250-9. DOI:10.1108/00070700810858664
https://doi.org/10.1108/0007070081085866... ^{- 5}5 Baumann A, Osman M, Burton M, Lumley S. Understanding Western Australian consumers’ views: acceptance of food produced using gene technology: a case of herbicide tolerant canola (Brassica napus L.). Environ Sci Pollut Res. 2005;12(1):56. DOI:10.1065/espr2005.01.003
https://doi.org/10.1065/espr2005.01.003... ^{, 12}12 Chembezi DM, Chaverest EL, Wheelock G, Sharma GC, Kebede E, Tegegne F. An econometric evaluation of producers’ preferences for mandatory labeling of genetically modified food products. J Food Distrib Res. 2008;39(1):36-44. ^{, 24}24 Irani T, Sinclair J. The effect of labeling genetically modified food on perceptions of accountability. J Appl Commun. 2004;88(1):29-42. ^{, 28}28 Loureiro ML, Hine S. Preferences and willingness to pay for GM labeling policies. Food Policy. 2004;29(5):467-83. DOI:10.1016/j.foodpol.2004.07.001
https://doi.org/10.1016/j.foodpol.2004.0... ^{, 29}29 Lü L. Chinese public understanding of the use of agricultural biotechnology: a case study from Zhejiang Province of China. J Zhejiang Univ Sci B. 2006;7(4):257-66. DOI:10.1631/jzus.2006.B0257
https://doi.org/10.1631/jzus.2006.B0257... ^{- 30}30 Lusk JL, House LO, Valli C, Jaeger SR, Moore M, Morrow B, et al. Consumer welfare effects of introducing and labeling genetically modified food. Econ Lett. 2005;88(3):382-8. DOI:10.1016/j.econlet.2005.03.009
https://doi.org/10.1016/j.econlet.2005.0... ^{, 32}32 Man-ser J, Tsu-tan F, Huang CL. A conjoint/logit analysis of consumers’ responses to genetically modified tofu in Taiwan. J Agric Econ. 2007;58(2):330-47. DOI:10.1111/j.1477-9552.2007.00100.x
https://doi.org/10.1111/j.1477-9552.2007... ^{, 40}40 Mucci A, Hough G. Perceptions of genetically modified foods by consumers in Argentina. Food Qual Prefer. 2004;15(1):43-51. DOI:10.1016/S0950-3293(03)00021-1.
https://doi.org/10.1016/S0950-3293(03)00... ^{, 46}46 Radas S, Teisl MF, Roe B. An open mind wants more: opinion strength and the desire for genetically modified food labeling policy. J Consum Aff. 2008;42(3):335-61. DOI:10.1111/j.1745-6606.2008.00111.x
https://doi.org/10.1111/j.1745-6606.2008... ^{, 47}47 Ramon D, Diamante A, Calvo MD. Food biotechnology and education. Electron J Biotechnol. 2008;11(5 Spec Iss):1-5. DOI:10.2225/vol11-issue5-fulltext-7
https://doi.org/10.2225/vol11-issue5-ful... ^{, 53}53 Shehata S. Attitudes of Japanese and Hawaiian consumers toward labeling genetically modified fruits. In: Martorell S, Guedes Soares C, Barnett J, editors. Safety, reliability and risk analysis: theory, methods and applications. London: CRC Press/Taylor & Francis Group; 2008. p.2285-8. ^{, 56}56 Subrahmanyan S, Cheng PS. Perceptions and attitudes of Singaporeans towards genetically modified food. J Consum Aff. 2000;34(2):269-90. DOI:10.1111/j.1745-6606.2000.tb00094.x
https://doi.org/10.1111/j.1745-6606.2000... ^{, 58}58 Teisl MF, Halverson L, O’Brien K, Roe B, Ross N, Vayda M. Focus group reactions to genetically modified food labels. AgBioForum. 2002;5(1):6-9. ^{, 60}60 Todt O, Muñoz E, González M, Ponce G, Estévez B. Consumer attitudes and the governance of food safety. Public Underst Sci. 2009;18(1):103-14. DOI:10.1177/0963662507078019
https://doi.org/10.1177/0963662507078019... ^,63 In 15.0%, they were in favor of voluntary labeling.⁹9 Brown JL, Ping Y. Consumer perception of risk associated with eating genetically engineered soybeans is less in the presence of a perceived consumer benefit. J Am Diet Assoc. 2003;103(2):208-14. DOI:10.1053/jada.2003.50029
https://doi.org/10.1053/jada.2003.50029... ^{, 23}23 Huffman WE, Rousu M, Shogren JF, Tegene A. The effects of prior beliefs and learning on consumers’ acceptance of genetically modified foods. J Econ Behav Organ. 2007;63(1):193-206. DOI:10.1016/j.jebo.2005.04.019
https://doi.org/10.1016/j.jebo.2005.04.0... ^{, 31}31 Lusk JL, Rozan A. Public policy and endogenous beliefs: the case of genetically modified food. J Agric Resour Econ. 2008;33(2):270-89. ^{, 43}43 Noussair C, Robin S, Ruffieux B. Do consumers not care about biotech foods or do they just not read the labels? Econ Lett. 2002;75(1):47-53. DOI:10.1016/S0165-1765(01)00594-8
https://doi.org/10.1016/S0165-1765(01)00... ^{, 52}52 Scholder EP, Bone PF. Stained by the label? Stigma and the case of genetically modified foods. J Public Policy Mark. 2008;27(1):69-82. DOI:10.1509/jppm.27.1.69
https://doi.org/10.1509/jppm.27.1... ^{, 61}61 Veeman MM, Hu W, Adamowicz WL. Consumers’ preferences for GM food and voluntary information access: a simultaneous choice analysis. Can J Agric Econ. 2009;57(2):241-67. DOI:10.1111/j.1744-7976.2009.01150.x
https://doi.org/10.1111/j.1744-7976.2009... Young people were in favor of mandatory labeling, as shown in certain studies conducted in educational institutions.⁴4 Batrinou AM, Spiliotis V, Sakellaris G. Acceptability of genetically modified maize by young people. Br Food J. 2008;110(3):250-9. DOI:10.1108/00070700810858664
https://doi.org/10.1108/0007070081085866... ^{, 47}47 Ramon D, Diamante A, Calvo MD. Food biotechnology and education. Electron J Biotechnol. 2008;11(5 Spec Iss):1-5. DOI:10.2225/vol11-issue5-fulltext-7
https://doi.org/10.2225/vol11-issue5-ful... Nutrition professionals and consumers agreed that mandatory labeling was necessary.³3 Bánáti D, Szabó JA. Knowledge and acceptance of genetically modified foodstuffs in Hungary. Acta Biol Szeged. 2006;50(3-4):115-9.

In the interventions in which participants received information, their wish for mandatory labeling depended on: whether the information received was positive (clearly in favor of GM products), the label did not seem to be important, and whether the information was negative (clearly against GM products) or neutral (technical information without connotations), they expected the labeling to be mandatory.²³23 Huffman WE, Rousu M, Shogren JF, Tegene A. The effects of prior beliefs and learning on consumers’ acceptance of genetically modified foods. J Econ Behav Organ. 2007;63(1):193-206. DOI:10.1016/j.jebo.2005.04.019
https://doi.org/10.1016/j.jebo.2005.04.0... ^{, 47}47 Ramon D, Diamante A, Calvo MD. Food biotechnology and education. Electron J Biotechnol. 2008;11(5 Spec Iss):1-5. DOI:10.2225/vol11-issue5-fulltext-7
https://doi.org/10.2225/vol11-issue5-ful... Consolidated negative attitudes were difficult to change.⁴4 Batrinou AM, Spiliotis V, Sakellaris G. Acceptability of genetically modified maize by young people. Br Food J. 2008;110(3):250-9. DOI:10.1108/00070700810858664
https://doi.org/10.1108/0007070081085866... ^{, 36}36 Miles S, Ueland O, Frewer LJ. Public attitudes towards genetically-modified food. Br Food J. 2005;107(4):246-62. DOI:10.1108/00070700510589521
https://doi.org/10.1108/0007070051058952... ^{, 61}61 Veeman MM, Hu W, Adamowicz WL. Consumers’ preferences for GM food and voluntary information access: a simultaneous choice analysis. Can J Agric Econ. 2009;57(2):241-67. DOI:10.1111/j.1744-7976.2009.01150.x
https://doi.org/10.1111/j.1744-7976.2009... The information received (neutral, positive or negative) was a decisive factor in acceptance or rejection of GM products.

Consumers did not demand labeling nor oppose GM products if they perceived benefits for themselves, for farming or for the environment, and, of course, if no health risk was perceived.⁵5 Baumann A, Osman M, Burton M, Lumley S. Understanding Western Australian consumers’ views: acceptance of food produced using gene technology: a case of herbicide tolerant canola (Brassica napus L.). Environ Sci Pollut Res. 2005;12(1):56. DOI:10.1065/espr2005.01.003
https://doi.org/10.1065/espr2005.01.003... ^{, 9}9 Brown JL, Ping Y. Consumer perception of risk associated with eating genetically engineered soybeans is less in the presence of a perceived consumer benefit. J Am Diet Assoc. 2003;103(2):208-14. DOI:10.1053/jada.2003.50029
https://doi.org/10.1053/jada.2003.50029... According to the interviewees, educational material should explain the risks and benefits GM poses to the environment and to human health. They also declare that the actual labeling system does not meet customers’ expectations.²⁰20 Gaivoronskaia G, Hvinden B. Consumers with allergic reaction to food: perception of and response to food risk in general and genetically modified food in particular. Sci Technol HumValues. 2006;31(6):702-3. DOI:10.1177/0162243906291867
https://doi.org/10.1177/0162243906291867...

The rapid expansion of GM products contrasted with professed lack of knowledge, as was found in 17.5% of the articles.¹1 Abdulkadri AO, Pinnock S, Tennant PF. Public perception of genetic engineering and the choice to purchase genetically modified food in Jamaica. J Food Agric Environ. 2007;5(2):8-12. ^{, 9}9 Brown JL, Ping Y. Consumer perception of risk associated with eating genetically engineered soybeans is less in the presence of a perceived consumer benefit. J Am Diet Assoc. 2003;103(2):208-14. DOI:10.1053/jada.2003.50029
https://doi.org/10.1053/jada.2003.50029... ^{, 28}28 Loureiro ML, Hine S. Preferences and willingness to pay for GM labeling policies. Food Policy. 2004;29(5):467-83. DOI:10.1016/j.foodpol.2004.07.001
https://doi.org/10.1016/j.foodpol.2004.0... ^{, 29}29 Lü L. Chinese public understanding of the use of agricultural biotechnology: a case study from Zhejiang Province of China. J Zhejiang Univ Sci B. 2006;7(4):257-66. DOI:10.1631/jzus.2006.B0257
https://doi.org/10.1631/jzus.2006.B0257... ^{, 32}32 Man-ser J, Tsu-tan F, Huang CL. A conjoint/logit analysis of consumers’ responses to genetically modified tofu in Taiwan. J Agric Econ. 2007;58(2):330-47. DOI:10.1111/j.1477-9552.2007.00100.x
https://doi.org/10.1111/j.1477-9552.2007... ^{, 53}53 Shehata S. Attitudes of Japanese and Hawaiian consumers toward labeling genetically modified fruits. In: Martorell S, Guedes Soares C, Barnett J, editors. Safety, reliability and risk analysis: theory, methods and applications. London: CRC Press/Taylor & Francis Group; 2008. p.2285-8. ^{, 63}63 Zhong F, Marchant MA, Ding Y, Lu K. GM Foods: a Nanjing case study of Chinese consumers’ awareness and potential attitudes. AgBioForum. 2002;5(4):136-44. In the interventions, consumers did not conclude that the tolerable level of GM material in the final product, of between 1.0% and 5.0%, made no difference to acceptance.²³23 Huffman WE, Rousu M, Shogren JF, Tegene A. The effects of prior beliefs and learning on consumers’ acceptance of genetically modified foods. J Econ Behav Organ. 2007;63(1):193-206. DOI:10.1016/j.jebo.2005.04.019
https://doi.org/10.1016/j.jebo.2005.04.0... ^{, 55}55 Smyth S, Phillips P. Labeling to manage marketing of GM foods. Trends Biotechnol. 2003;21(9):389-93. DOI:10.1016/S0167-7799(03)00197-5
https://doi.org/10.1016/S0167-7799(03)00... Nor did they find differences in accepting products manufactured using GM, but not containing it, and products that did contain GM.⁸8 Bredahl L. Determinants of consumer attitudes and purchase intentions with regard to genetically modified foods: results of a cross-national survey. Aarhus (Denmark): Centre for Market Surveillance, Research and Strategy for the Food Sector; 2000. (Working Paper, 69). The population underestimated the quantity of GN products they consumed.¹⁵15 Dannenberg A, Scatasta S, Sturm B. Mandatory versus voluntary labeling of genetically modified food: evidence from an economic experiment. Agric Econ. 2011;42(3):373-86. DOI:10.1111/j.1574-0862.2010.00520.x
https://doi.org/10.1111/j.1574-0862.2010... ^{, 23}23 Huffman WE, Rousu M, Shogren JF, Tegene A. The effects of prior beliefs and learning on consumers’ acceptance of genetically modified foods. J Econ Behav Organ. 2007;63(1):193-206. DOI:10.1016/j.jebo.2005.04.019
https://doi.org/10.1016/j.jebo.2005.04.0... ^{, 56}56 Subrahmanyan S, Cheng PS. Perceptions and attitudes of Singaporeans towards genetically modified food. J Consum Aff. 2000;34(2):269-90. DOI:10.1111/j.1745-6606.2000.tb00094.x
https://doi.org/10.1111/j.1745-6606.2000...

DISCUSSION

As can be seen in the results, the consumer expressed a preference for non-genetically modified products but stated they would buy the article with the best price, in a market that welcomes new technologies. The population was shown to be in favor of mandatory labeling for GM products, although some studies show a preference for voluntary labeling. A lack of knowledge of GM was shown, as was, in some cases, an underestimation of the quantity consumed.

The impact of GM products is difficult, if not impossible, for the consumer to determine. However, it is assumed that their market, and consumption, would be affected if it was marked on the label that they were GM, the products being stigmatized.⁵²52 Scholder EP, Bone PF. Stained by the label? Stigma and the case of genetically modified foods. J Public Policy Mark. 2008;27(1):69-82. DOI:10.1509/jppm.27.1.69
https://doi.org/10.1509/jppm.27.1... Reading the selected articles revealed consumer uncertainty at not being able to distinguish easily between GM and non-GM products.⁸8 Bredahl L. Determinants of consumer attitudes and purchase intentions with regard to genetically modified foods: results of a cross-national survey. Aarhus (Denmark): Centre for Market Surveillance, Research and Strategy for the Food Sector; 2000. (Working Paper, 69). ^{, 11}11 Carlsson F, Frykblom P, Lagerkvist CJ. Consumer benefits of labels and bans on GM foods: choice experiments with Swedish consumers. Am J Agric Econ. 2007;89(1):152-61. DOI:10.1111/j.1467-8276.2007.00969.x
https://doi.org/10.1111/j.1467-8276.2007... ^{, 14}14 Costa-Font M, Gil JM, Traill WB. Consumer acceptance, valuation of and attitudes towards genetically modified food: review and implications for food policy. Food Policy. 2008;33(2):99-111. DOI:10.1016/j.foodpol.2007.07.002
https://doi.org/10.1016/j.foodpol.2007.0... ^{, 23}23 Huffman WE, Rousu M, Shogren JF, Tegene A. The effects of prior beliefs and learning on consumers’ acceptance of genetically modified foods. J Econ Behav Organ. 2007;63(1):193-206. DOI:10.1016/j.jebo.2005.04.019
https://doi.org/10.1016/j.jebo.2005.04.0... This would be solved by one single, standardized label.¹⁵15 Dannenberg A, Scatasta S, Sturm B. Mandatory versus voluntary labeling of genetically modified food: evidence from an economic experiment. Agric Econ. 2011;42(3):373-86. DOI:10.1111/j.1574-0862.2010.00520.x
https://doi.org/10.1111/j.1574-0862.2010...

The responses to the studies were partly determined by the type of intervention conducted: while the results varied in the personal, telephone and mail results, the desire for mandatory labeling was higher after information was provided. The same occurred in groups, when the information provided to the population was neutral or negative towards the technology. Although mandatory labeling of GM products does not seem economically justifiable in all countries, it is a necessary alternative, offering consumers the information they are demanding.²⁸28 Loureiro ML, Hine S. Preferences and willingness to pay for GM labeling policies. Food Policy. 2004;29(5):467-83. DOI:10.1016/j.foodpol.2004.07.001
https://doi.org/10.1016/j.foodpol.2004.0... ^{, 55}55 Smyth S, Phillips P. Labeling to manage marketing of GM foods. Trends Biotechnol. 2003;21(9):389-93. DOI:10.1016/S0167-7799(03)00197-5
https://doi.org/10.1016/S0167-7799(03)00...

Sociodemographic data (age, sex, education) do not provide conclusive data as, whereas in some articles they appeared to be significant,⁴⁶46 Radas S, Teisl MF, Roe B. An open mind wants more: opinion strength and the desire for genetically modified food labeling policy. J Consum Aff. 2008;42(3):335-61. DOI:10.1111/j.1745-6606.2008.00111.x
https://doi.org/10.1111/j.1745-6606.2008... ^{, 63}63 Zhong F, Marchant MA, Ding Y, Lu K. GM Foods: a Nanjing case study of Chinese consumers’ awareness and potential attitudes. AgBioForum. 2002;5(4):136-44. in others they were not.²³23 Huffman WE, Rousu M, Shogren JF, Tegene A. The effects of prior beliefs and learning on consumers’ acceptance of genetically modified foods. J Econ Behav Organ. 2007;63(1):193-206. DOI:10.1016/j.jebo.2005.04.019
https://doi.org/10.1016/j.jebo.2005.04.0...

The higher quantity of interventions performed in the USA, a country in which labeling is voluntary, may be due to these products having been included on the shopping list since this technology began.^ee Gruère GP, Carter CA, Farzin YH. Explaining international differences in genetically modified food labeling regulations. In: Annual Meeting of the American Agricultural Economics Association; 2004 Aug 1-4; Denver, Colorado. Paper Nº 20341. The most recent interventions did not take place in this country. The lack of population studies since 2007 may be a consequence of this technology being gradually, progressively incorporated and different legislations have adapted themselves to this new order. Tacit acceptance of GM may explain the lack of any more studies¹⁹19 Frewer LJ, Bergmann K, Brennan M, Lion R, Meertens R, Rowe G, et al. Consumer response to novel agri-food technologies: implications for predicting consumer acceptance of emerging food technologies. Trends Food Sci Technol. 2011;22(8):442-56. DOI:10.1016/j.tifs.2011.05.005
https://doi.org/10.1016/j.tifs.2011.05.0... and, perhaps, the lack of knowledge concerning GM.

Consumers who stated they paid attention to labels were those who were shown to have the least desire to consume GM products.¹1 Abdulkadri AO, Pinnock S, Tennant PF. Public perception of genetic engineering and the choice to purchase genetically modified food in Jamaica. J Food Agric Environ. 2007;5(2):8-12. ^{, 10}10 Bukenya JO, Wright NR. Determinants of consumer attitudes and purchase intentions with regard to genetically modified tomatoes. Agribusiness. 2007;23(1):117-30. DOI:10.1002/agr.2010
https://doi.org/10.1002/agr.2010... ^{, 25}25 Kim RB. A multi-attribute model of Japanese consumer’s purchase intention for GM foods. Agric Econ Czech. 2010;56(10):449-59. They were in favor of specific labels, for the right to knowledge and to making informed decisions.⁵⁶56 Subrahmanyan S, Cheng PS. Perceptions and attitudes of Singaporeans towards genetically modified food. J Consum Aff. 2000;34(2):269-90. DOI:10.1111/j.1745-6606.2000.tb00094.x
https://doi.org/10.1111/j.1745-6606.2000... ,⁶⁰60 Todt O, Muñoz E, González M, Ponce G, Estévez B. Consumer attitudes and the governance of food safety. Public Underst Sci. 2009;18(1):103-14. DOI:10.1177/0963662507078019
https://doi.org/10.1177/0963662507078019...

For some consumers, the GM concept was associated with a loss of utility.⁵⁵55 Smyth S, Phillips P. Labeling to manage marketing of GM foods. Trends Biotechnol. 2003;21(9):389-93. DOI:10.1016/S0167-7799(03)00197-5
https://doi.org/10.1016/S0167-7799(03)00... ^{, 61}61 Veeman MM, Hu W, Adamowicz WL. Consumers’ preferences for GM food and voluntary information access: a simultaneous choice analysis. Can J Agric Econ. 2009;57(2):241-67. DOI:10.1111/j.1744-7976.2009.01150.x
https://doi.org/10.1111/j.1744-7976.2009... Thus, it did not seem, to them, a good idea to label conventional products as «GM free».⁴⁷47 Ramon D, Diamante A, Calvo MD. Food biotechnology and education. Electron J Biotechnol. 2008;11(5 Spec Iss):1-5. DOI:10.2225/vol11-issue5-fulltext-7
https://doi.org/10.2225/vol11-issue5-ful... It was more credible to label GM products in contrast to non-GM products.⁴⁶46 Radas S, Teisl MF, Roe B. An open mind wants more: opinion strength and the desire for genetically modified food labeling policy. J Consum Aff. 2008;42(3):335-61. DOI:10.1111/j.1745-6606.2008.00111.x
https://doi.org/10.1111/j.1745-6606.2008... ^{, 58}58 Teisl MF, Halverson L, O’Brien K, Roe B, Ross N, Vayda M. Focus group reactions to genetically modified food labels. AgBioForum. 2002;5(1):6-9. Including contact information partly resolved uncertainty about GM, even more so when the information was supported by certification by a state agency.⁴4 Batrinou AM, Spiliotis V, Sakellaris G. Acceptability of genetically modified maize by young people. Br Food J. 2008;110(3):250-9. DOI:10.1108/00070700810858664
https://doi.org/10.1108/0007070081085866... ^{, 18}18 Februhartanty J, Widyastuti TN, Iswarawanti DN. Attitudes of agricultural scientists in Indonesia towards genetically modified foods. Asia Pac J Clin Nutr. 2007;16(2):375-80. ^{, 46}46 Radas S, Teisl MF, Roe B. An open mind wants more: opinion strength and the desire for genetically modified food labeling policy. J Consum Aff. 2008;42(3):335-61. DOI:10.1111/j.1745-6606.2008.00111.x
https://doi.org/10.1111/j.1745-6606.2008... ^{, 55}55 Smyth S, Phillips P. Labeling to manage marketing of GM foods. Trends Biotechnol. 2003;21(9):389-93. DOI:10.1016/S0167-7799(03)00197-5
https://doi.org/10.1016/S0167-7799(03)00... ^{, 58}58 Teisl MF, Halverson L, O’Brien K, Roe B, Ross N, Vayda M. Focus group reactions to genetically modified food labels. AgBioForum. 2002;5(1):6-9.

The negative perception of GM products, in contrast with non-Gm products,⁴4 Batrinou AM, Spiliotis V, Sakellaris G. Acceptability of genetically modified maize by young people. Br Food J. 2008;110(3):250-9. DOI:10.1108/00070700810858664
https://doi.org/10.1108/0007070081085866... ^{, 24}24 Irani T, Sinclair J. The effect of labeling genetically modified food on perceptions of accountability. J Appl Commun. 2004;88(1):29-42. ^{, 52}52 Scholder EP, Bone PF. Stained by the label? Stigma and the case of genetically modified foods. J Public Policy Mark. 2008;27(1):69-82. DOI:10.1509/jppm.27.1.69
https://doi.org/10.1509/jppm.27.1... may be due to consumers considering the non-GM products cause fewer environmental problems.³⁹39 Moon W, Balasubramanian SK. Public perceptions and willingness-to-pay a premium for non-GM foods in the US and UK. AgBioForum. 2001;4(3-4):221-31. ^{, 40}40 Mucci A, Hough G. Perceptions of genetically modified foods by consumers in Argentina. Food Qual Prefer. 2004;15(1):43-51. DOI:10.1016/S0950-3293(03)00021-1.
https://doi.org/10.1016/S0950-3293(03)00... ^{, 46}46 Radas S, Teisl MF, Roe B. An open mind wants more: opinion strength and the desire for genetically modified food labeling policy. J Consum Aff. 2008;42(3):335-61. DOI:10.1111/j.1745-6606.2008.00111.x
https://doi.org/10.1111/j.1745-6606.2008... In the case of the article in which reports in newspapers,⁶³63 Zhong F, Marchant MA, Ding Y, Lu K. GM Foods: a Nanjing case study of Chinese consumers’ awareness and potential attitudes. AgBioForum. 2002;5(4):136-44. it was noted that articles on GM products were more abundant and in a negative sense from 1995 onwards. In the US, greater desire for mandatory labeling of GM products began with the appearance of StarLink corn in the food chain.³⁴34 McGarry-Wolf M, McDonell J, Domegan C, Yount H. Consumer attitudes towards GM food in Ireland and the USA. In: Evenson RE, Santaniello V, editors. Consumer acceptance of genetically modified foods. Wallingford (UK): CABI Publishing; 2004. p.143-54.

Distributors and wholesalers of GM products found traceability important, and even supported it, but they prefer not to label because of the costs and possible adverse consumer reaction.⁶6 Bett C, Ouma JO, De Groote H. Perspectives of gatekeepers in the Kenyan food industry towards genetically modified food. Food Policy. 2010;35(4):332-40. DOI:10.1016/j.foodpol.2010.01.003
https://doi.org/10.1016/j.foodpol.2010.0... ^{, 26}26 Knight JG, Mather DW, Holdsworth DK. Genetically modified crops and country image of food exporting countries. Br Food J. 2005;107(9):653-62. DOI:10.1108/00070700510615035
https://doi.org/10.1108/0007070051061503... Nor did these wholesalers and distributors show the desire to cease importation from countries producing GM items.²⁶26 Knight JG, Mather DW, Holdsworth DK. Genetically modified crops and country image of food exporting countries. Br Food J. 2005;107(9):653-62. DOI:10.1108/00070700510615035
https://doi.org/10.1108/0007070051061503...

When consumers accept GM products, they expect more competitive prices¹⁰10 Bukenya JO, Wright NR. Determinants of consumer attitudes and purchase intentions with regard to genetically modified tomatoes. Agribusiness. 2007;23(1):117-30. DOI:10.1002/agr.2010
https://doi.org/10.1002/agr.2010... ^{, 11}11 Carlsson F, Frykblom P, Lagerkvist CJ. Consumer benefits of labels and bans on GM foods: choice experiments with Swedish consumers. Am J Agric Econ. 2007;89(1):152-61. DOI:10.1111/j.1467-8276.2007.00969.x
https://doi.org/10.1111/j.1467-8276.2007... ^{, 23}23 Huffman WE, Rousu M, Shogren JF, Tegene A. The effects of prior beliefs and learning on consumers’ acceptance of genetically modified foods. J Econ Behav Organ. 2007;63(1):193-206. DOI:10.1016/j.jebo.2005.04.019
https://doi.org/10.1016/j.jebo.2005.04.0... ^{, 43}43 Noussair C, Robin S, Ruffieux B. Do consumers not care about biotech foods or do they just not read the labels? Econ Lett. 2002;75(1):47-53. DOI:10.1016/S0165-1765(01)00594-8
https://doi.org/10.1016/S0165-1765(01)00... and are prepared to pay a little more, a premium, if the label assures them that the product is non-GM.¹1 Abdulkadri AO, Pinnock S, Tennant PF. Public perception of genetic engineering and the choice to purchase genetically modified food in Jamaica. J Food Agric Environ. 2007;5(2):8-12. ¹1 Abdulkadri AO, Pinnock S, Tennant PF. Public perception of genetic engineering and the choice to purchase genetically modified food in Jamaica. J Food Agric Environ. 2007;5(2):8-12. ^{, 23}23 Huffman WE, Rousu M, Shogren JF, Tegene A. The effects of prior beliefs and learning on consumers’ acceptance of genetically modified foods. J Econ Behav Organ. 2007;63(1):193-206. DOI:10.1016/j.jebo.2005.04.019
https://doi.org/10.1016/j.jebo.2005.04.0... ^,28,39,55 Although they state that they prefer non-GM to GM products, evidence from supermarkets shows that consumers pay more attention to price than to containing GM, or otherwise.¹¹11 Carlsson F, Frykblom P, Lagerkvist CJ. Consumer benefits of labels and bans on GM foods: choice experiments with Swedish consumers. Am J Agric Econ. 2007;89(1):152-61. DOI:10.1111/j.1467-8276.2007.00969.x
https://doi.org/10.1111/j.1467-8276.2007... ^{, 33}33 Marks L, Kalaitzandonakes NG, Vickner S. Consumer purchasing behaviour towards GM foods in the Netherlands. In: Evenson RE, Santaniello V, editors. Consumer acceptance of genetically modified foods. Wallingford (UK): CABI Publishing; 2004. p.23-39.

There is disparity in opinions concerning GM products, based on lack of knowledge of the topic in general (% of tolerance, presence or absence of GM in food, GM concept, among others). Despite this lack of information, the population does not refrain from expressing their opinion. The information and sources from which the consumer receives it affect the way in which the market perceives GM products. This is directly related to the way in which they want to be informed by the label. Educational materials should present explanations of the risks and benefits GM poses to the environment and to human health.⁷7 Bougherara D, Combris P. Eco-labeled food products: what are consumers paying for? Eur Rev Agric Econ. 2009;36(3)321-41. DOI:10.1093/erae/jbp023
https://doi.org/10.1093/erae/jbp023... ^{, 55}55 Smyth S, Phillips P. Labeling to manage marketing of GM foods. Trends Biotechnol. 2003;21(9):389-93. DOI:10.1016/S0167-7799(03)00197-5
https://doi.org/10.1016/S0167-7799(03)00... The review detected that current labeling of GM products is not effective at informing the consumer.

It would be interesting to continue in the same vein as these articles, investigating the population’s opinion and knowledge of these technologies. This allows an evaluation of the evolution of people’s interest in what they consume and their understanding of labeling.

Although it is preferable to base a systematic review on studies with adequate follow up periods, as well as limit the review to studies with an appropriate design, guaranteeing scientific evidence of the final conclusions, it was decided to include all of the studies found that were deemed relevant, having studied behavior in relation to labeling and genetically modified food, and having passed the quality evaluation (STROBE).

To conclude, labeling needs to be homogeneous and explain the degree of tolerance of GM products, compared with non-GM, as well as explaining GM content, or otherwise, and the way in which these articles of consumption are manufactured. The label should also include contact data. In practice, consumers express a preference for non-GM products, but buy the article which has the best price in a market which welcomes new technologies.³⁷37 Miljus-Djukic J, Banovic B, Jovanovic Z, Majic D, Milisavljevic M, Samardžic J, et al. Abundance of soybean Roundup Ready modification in food and feed samples from Serbian retail markets. Rom Biotechnol Lett. 2010;15(1 Suppl):102-9. ^{, 39}39 Moon W, Balasubramanian SK. Public perceptions and willingness-to-pay a premium for non-GM foods in the US and UK. AgBioForum. 2001;4(3-4):221-31.

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