Consumer Acceptance of Genetically Modified (GM)
Foods: The Case of GM Biofortified Cassava in the
Northeast of Brazil
Carolina Gonzalez1,4, Nancy Johnson2 and Matin Qaim3
1International Center for Tropical Agriculture– CIAT, 2 International Livestock Research Institute (ILRI), 3 Göttingen University, 4Hoheheim University
Contacto: c.gonzalez@cgiar.org
Introduction
Biofortified staple foods are currently being developed to reduce problems of micronutrient malnutrition among the poor. Research mostly builds on
conventional breeding techniques. Yet there are also species where certain micronutrients are absent, or occur only in very small amounts, so that
use of biotechnology seems more promising. This is the case of cassava and provitamin A. Genetic modification could potentially boost provitamin A
contents, thus more effectively reducing problems of vitamin A deficiency. On the other hand, genetically modified (GM) cassava might raise
consumer concerns about health and environmental risks . The present study examines consumer attitudes towards GM cassava in the Northeast
(NE) of Brazil.
Methodology Female respondents and households with small children have a higher
We assess acceptance of GM biofortified cassava among consumers in WTP; those who have ethical concerns, or are particularly worried
NE Brazil by estimating their willingness to pay (WTP). Contingent about health risks of GM crops, have a lower WTP. Household income
valuation (CV) and choices modeling (CM) techniques were employed to levels do not appear to have a significant effect separate from other
estimate consumer WTP. socio-economic characteristics (see Table 2).
Using the CM approach we analyzed the trade-offs between different
cassava characteristics and estimated the partial WTP for each
attribute. For the vitamin A alone, the average consumer is willing to
pay premium of 160%. However, a discount is required for the cassava
colour change from white to yellow (-29%), and an additional discount
results from the fact that the cassava is GM (-61%) (see Table 3). The
Figure 1. Map of NE Brazil and Pernambuco.
CM approach generates a mean WTP of 70% over current market
CV techniques are often used to analyze individual preferences and elicit prices.
the monetary value of goods that are not yet marketed. CM is a tool to Table 3. Rank-ordered logit model for GM cassava
determine how consumers value different attributes of a certain good
Variables Coefficient Std. error WTP
(Bateman, et al., 2002).
Price 1.93*** 0.70
Results GM status 0.91*** 0.09 -0.47
Using the four-point scale data about consumer support of GM cassava, Vitamin A content -2.36*** 0.15 1.23
we estimated a model to explore the factors underlying consumer Colour (yellow) 0.42*** 0.09 -0.22
perceptions (see Table 1). Consumers who trust the regulatory Log likelihood -1105.95
authorities are more supportive of the GM technology, while people who Chi-squared 419.53***
are concerned about GM health risks tend to oppose its introduction. N=414; *, **, *** statistically significant at 10%, 5% and 1% level, respectively
Table 1. Ordered logit model for explaining consumer support of GM cassava
Variables Coefficient Std. error
Age 0.02* 0.01
Children <5 0.14 0.25
Education 0.03 0.03
Per capita household income 0.00 0.00
Figure 2. “Choice sets” presented to responders and consumers in the NE of Brazil
Trust in regulatory authorities 0.55** 0.22
Perceived GM health risks -3.05*** 0.46 Discussion
Access to mass media 0.48* 0.29 What does the estimated premium mean in terms of household budget
Chi-squared 54.68*** share? Mean monthly per capita expenditure for cassava is around 3
N=414; *, **, *** statistically significant at 10%, 5% and 1% level, respectively
reais ($1.42), accounting for 1.8% of average household income. A 64%
price premium for GM cassava would increase monthly expenditure to
Based on the CV approach, on average, consumers are willingness to 4.9 reais, or 3% of household income, indicating the strength of
pay 0.49 reais more (a 64% price premium) for GM cassava than for preference/acceptance for more nutritious cassava. Nonetheless, the
traditional cassava without vitamin A. idea is not to really sell GM biofortified cassava at a premium. The large
Table 2. WTP model for GM cassava WTP is simply a clear indication of positive acceptance levels and an
expected increase in consumer utility through GM cassava.
Variables Coefficient Std. error
Cassava price paid (reais/kg) 0.56*** 0.11 Conclusions
Female respondent 0.14** 0.07  75% of all respondents in our survey said they would support the
Children <5 0.07* 0.04 introduction of this new technology.
Per capita household income 0.00 0.00  Based on CV and CM techniques, mean WTP is estimated at 64-70%
Cassava consumption (per week) -0.03*** 0.01 above market prices for cassava.
Perceived GM health risks -0.29*** 0.08  The results also suggest that acceptance would be higher still if
Trust in regulatory authorities -0.02 0.04 provitamin A were introduced to cassava through conventional
Access to mass media 0.04 0.05 breeding.
Willingness to eat new products a. Average willingness -0.08 0.07 Acknowledgements
(reference is high willingness) b. Low willingness -0.07 0.08 The financial support CIAT and the HarvestPlus Challenge Program are gratefully
c. Avoid -0.01 0.08 acknowledged. A especially grateful to Brazilian consumers, who where the key to the
outcome of this study.
Preferred way to increase vitamin A a. Conventional -0.27*** 0.04
(reference is through GM) b. Indifferent -0.25*** 0.08 References
Bateman, I.J., Carson, R.T., Day B., Hanemann, M., Hanley, N. Hett, T., Jones-Lee, M.
Prior knowledge about GM crops 0.09* 0.05
Loomes, G., Mourato, S., Özdemiroglu, E., Pearce, D.W, Sugden, R. and Swanson, J.
Chi-squared 104.07*** Economic Valuation with Stated Preference Techniques: A Manual. Edward Elgar,
N=414; *, **, *** statistically significant at 10%, 5% and 1% level, respectively Cheltenham, 2002.