Groundnuts (peanuts) are widely used in Senegalese cuisine and are critical for poverty reduction strategies targeted to rural households. In fact, groundnuts are grown by 52% of Senegalese households in extreme poverty. However, every stage of their production, processing and storage carry a risk of microbial and fungal contamination that can lead to foodborne illnesses. Understanding contamination levels, household awareness of food safety hazards and farmers’ attitudes towards interventions to reduce the risk of foodborne diseases is critical to strengthening food safety in Senegal. In a project funded by the Feed the Future Innovation Lab for Food Safety (FSIL), an interdisciplinary team at Purdue University partnered with the Institut Sénégalais de Recherches Agricoles (ISRA) to quantify chemical and microbial contamination levels in groundnuts that smallholder farmers in Senegal eat, sell and store for seed. Surveys of 250 smallholder farmers in the country's peanut basin, as well as testing for chemical and microbial pathogens in their stored groundnuts, provided four interesting results.

1. Awareness of foodborne diseases

We found that awareness of foodborne diseases and the pathogens that cause them is still very low in rural Senegal. Only 20% of groundnut producers surveyed knew of aflatoxins, carcinogenic toxins produced by a family of fungi that commonly contaminate groundnuts. In addition, we learned that prior to participating in the study, only 22% knew about the possibility of bacterial contamination of food. Words referring to aflatoxins and specific pathogens such as E. coli and Salmonella do not exist in the local languages in our survey area. Strategies to inform smallholder producers about food safety should therefore be adapted to this context, for example using videos, pictograms or images. This approach will be helpful in reinforcing the importance of food safety not only on their crops but also on other types of food consumed in the household. Increasing awareness of chemical and microbial contamination is critical to creating systemic change in food safety, by incentivizing consumers to pay premiums for safer food and enhancing the willingness of producers to adopt improved planting, drying and storage practices that reduce the risk of contamination in their crops.

2. Chemical contaminants: Aflatoxins

In 87% of groundnut samples, levels of aflatoxins were below the safety threshold set by the European Union — 4 parts per billion (ppb) — however, 8% contained very high levels, above 100 ppb. This suggests that a non-trivial share of farmers had samples exhibiting aflatoxin levels above the EU standard, and that some groundnuts were extremely unsafe for human consumption. To date, it has been shown that for crops susceptible to contamination with aflatoxins, quality and safety can be improved by promoting the use of biocontrol technologies that help control aflatoxins during plant growth, the use of plastic tarps during drying and improved storage.

3. Microbial contaminants: Coliforms and Enterobacteriaceae

The groundnuts sampled contained high levels of coliforms and Enterobacteriaceae:  97% of samples had coliforms above the U.S. limit for groundnuts destined for raw consumption and 94.5% contained Enterobacteriaceae above the same limit (1 log of colony forming units per gram). The health impacts of these high levels of contamination are unknown. Few households reported consuming raw groundnuts (7%), but paste (pâte d’arachide) and powder are commonly used to make sauces to accompany staple foods. Follow-up is needed to determine whether bacteria are sufficiently destroyed during cooking and processing of paste and powder or if they persist in these processed meals and contribute to the incidence of gastrointestinal diseases.

4. Adoption of new technologies: The case of Aflasafe

The biocontrol product Aflasafe can significantly reduce aflatoxins in groundnuts during plant growth. However, very few farmers we interviewed were aware of the technology, even though Senegal is one of six African countries where the product is being commercially promoted. To evaluate the potential for local adoption of this technology, we assessed farmers’ willingness to pay for Aflasafe. At the time of our survey, 65% of participants valued the technology at its current market price or above. Future work will focus on understanding this demand, how it changes over time and if willingness to pay evolves with adoption of the technology within farmers’ social networks.

Next steps

Food systems in sub-Saharan Africa, including in Senegal, face several simultaneous challenges. These systems need to provide safe and nutritious food to a growing population whose consumption patterns are rapidly changing through urbanization and the emergence of a middle class. They also need to abide by international food safety regulations to access international markets and increase lucrative exports. In the coming years, strengthening food safety will require a better understanding of the extent of contamination in foods produced and consumed in Senegal — widespread food surveillance — and the detection of foodborne hazards in different commodities. In the case of groundnuts produced in Senegal, these are essential steps to: (i) take advantage of growing confectionery groundnut markets in Africa and Asia and, in turn, boost rural households’ income and welfare; and (ii) protect local consumers and reduce the health and economic burden of foodborne diseases.

Additionally, rigorous testing of the impact of pre- and post-harvest strategies is needed to improve production practices and increase the safety of crops for food and feed. The COVID-19 pandemic and the large number of foodborne diseases in sub-Saharan Africa have demonstrated the importance of food safety issues. Funding to identify better farming and production practices could accelerate the scaling up of successful approaches and boost food safety, nutrition and rural incomes in Senegal.

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References

Bandyopadhyay, R., Atehnkeng, J., Ortega-Beltran, A., Akande, A., Falade, T. D. O. and Cotty, P. J. (2019). "'Ground-Truthing' Efficacy of Biological Control for Aflatoxin Mitigation in Farmers’ Fields in Nigeria: From Field Trials to Commercial Usage, a 10-Year Study." Frontiers in Microbiology, 10. https://doi.org/10.3389/fmicb.2019.02528

Bauchet, J., Prieto, S. and Ricker‐Gilbert, J. (2021). "Improved Drying and Storage Practices that Reduce Aflatoxins in Stored Maize: Experimental Evidence from Smallholders in Senegal." American Journal of Agricultural Economics, 103, 296–316. https://doi.org/10.1111/ajae.12106

Magnan, N., Hoffmann, V., Garrido, G., Kanyam, F. A. and Opoku, N. (2019). "Information, technology, and market rewards: Incentivizing aflatoxin control in Ghana." International Food Policy Research Institute. https://doi.org/10.2499/p15738coll2.133451