In Nigeria, traditional non-alcoholic cereal-based beverages are popular within the low-income populations due to their lower cost and assumed nutritional content. Kunun-zaki, a non-alcoholic beverage popular in Northern Nigeria is prepared from cereals (millet, sorghum and maize) that are prone to toxigenic fungi that produce mycotoxins which can be transferred to the beverage during processing. It is served to quench thirst and culturally during social gatherings and traditional ceremonies. It has nutritional value, is used as a weaning food for infants, a source of income, contribute to variety in the diet and the food security.
Mycotoxins are toxic secondary metabolites of fungi produced by toxigenic fungal strains that contaminate food and agricultural products, posing serious health risks to humans and animals. Aflatoxins, fumonisins, ochratoxins A, deoxynivalenol and zearalenone are the most toxicologically significant mycotoxins and are produced by Aspergillus, Fusarium and Penicillium spp. Traditional fermentation methods have been shown to significantly reduce mycotoxins in fermented foods, depending on initial grain mycotoxin content, however, previous research found mycotoxins in kunun-zaki, albeit in reduced amounts.
Currently there is no optimized procedure for processing kunun-zaki. Variations in its raw materials, processing methods, and absence of standardized procedure might compromise its quality and safety. This research will optimize the fermentation process to enhance the quality of kunun-zaki concerning mycotoxins reduction and to identify steps in kunun-zaki processing for targeted interventions to reduce mycotoxin contamination, and enhance safety and quality.
The study will utilize a cross-sectional mixed-method survey design involving data collection complemented with desk review, and quantitative methods to describe the kunun-zaki value chain. Structured questionnaires transcribed into a kobo tool will be used to obtain quantitative data from respondents along the value chain. Respondents will be stratified into 4 nodes based on the value chain, which includes, consumers, processors, sellers of raw materials and producers of raw materials.
The 5 major mycotoxins, aflatoxins, fumonisins, deoxynivalenol, zearalenone and ochratoxins in crops and kunun zaki will be quantified using antibody-based rapid lateral flow method. Positive samples will be validated using liquid chromatography in tandem with mass spectrometry (LC-MS/MS). Toxigenic fungi will be isolated from the crops using the direct kernel plating procedure and identified microscopically and genetically.
Critical Control Points (CCPs) will be identified through identification and description of the main quality hazards in the kunun-zaki value chain by representing the transformation process workflow (operation units) that describes the standard average processes of kunun-zaki. Each step in kunun-zaki processing will then be precisely described using the 5M approach as described by Ishikawa and Loftus, (1990).
Optimized kunun-zaki will be analyzed for the mycotoxin content before and after fermentation using LC-MS, and high-resolution MS (HRMS) to map degradation products to demonstrate the potential effect of fermentation on mycotoxin reduction. Cultivable microbial communities from optimized kunun-zaki and raw materials (mix of ingredients) will be isolated as described by Ferrara et al. (2021). The cultivable microorganisms isolated from raw materials and kunun-zaki will be subjected to molecular characterization (repetitive element (REP)-PCR) and identification (sequencing of 16S rRNA and 26S rRNA genes). Genomic DNA will be extracted using the microbial food culture technique as described by Cocolin et al. (2023), then investigated using high-throughput sequencing to study the composition of the microbiota and allow the reconstruction of the taxonomic networks typical of fermented foods.
This work will contribute to improving and strengthening the food safety system by focusing on value chain of kunun-zaki, an economic relevant and high nutritional important beverage in the local diet of Nigerians, but is prone to mycotoxin contamination, thus compromising food safety and contributing to long-term adverse health effects of consumers.