Microbiological contamination of fermented cassava products sold in local markets, Yaounde (Cameroon)

Abstract:

Locally processed cassava is a desirable staple food in Cameroon; however, microbiological hazards during processing, handling and/or consumption have been significantly ignored. This study investigated the microbiological quality of five fermented cassava products locally called Kum-kum, Garri, Water-fufu, Bobolo and Mintoumba, which are widely consumed and sold in local markets across Yaounde. A total of 200 samples (n=40 per food product) were analysed using microbial culture techniques. In addition, three parameters, moisture content, water activity, and pH were measured as indicators of each product shelf-life. The results showed that all food types were slightly acidic, ranging between 4.1 (Water-fufu) and 6.3 (Garri). Moisture and water activity were highest in Water-fufu (58.52% and 0.94) and lowest in Kum-kum (3.35% and 0.51) respectively. The presence of E. coli and coliforms (5.61log10 CFU/g to 8.67log10 CFU/g) indicated potential faecal contamination and improper product storage. Specifically, the mean total viable bacteria, yeast and mould count indicated unsatisfactory levels for human consumption and ranged from 5.33log10 CFU/g (Mintoumba) to 7.22log10 CFU/g (Water-fufu), and 4.23log10 CFU/g (Garri) to 6.59log10 CFU/g (Kum-kum) respectively. In terms of foodborne pathogens, all cassava products contained at least one pathogen of public health significance. Water-fufu significantly contained Bacillus cereus (33%), Vibrio cholerae (28%), Salmonella spp. (23%) and Campylobacter spp. (13%), and Staphylococci and Listeria monocytogenes were most prevalent in Kum-kum at 21% and 13% respectively. The results showed the short shelf-life characteristics of fermented cassava products consumed in Cameroon, and importantly, indicated a significant route of human exposure to enteric pathogens.