Microbiological screening of street-vended groundnut cake, Kulikuli and natural spices for reducing microbial contamination in the food snack

Abstract

Groundnut (Arachis hypogea) and its popular derivative snack-product, kulikuli are particularly prone to contamination by a wide variety of toxigenic microorganisms due to its high nutritive content. Peanuts are rich in calories and contain many nutrients, minerals, antioxidants, and vitamins that are essential for optimum health. Samples were collected from five selected sites within the Mowe market, Ogun State, SouthWest Nigeria from two experimental blocks and compared for microbial quality with laboratory-prepared samples treated with plant-derived natural spices. Aliquots of diluents of the treatments were inoculated in duplicates onto Eosin Methylene Blue (EMB) agar and Potato dextrose agar (PDA) to screen for coliform bacteria and fungi respectively to obtain the total colony count (TCC). The bacterial species isolated from the market samples include Serratia fonticola, Proteus vulgaris, while Morganella morganii and Proteus vulgaris were isolated from laboratory samples. Conversely, Rhizopus nigricans, Penicilium nigricans, Mucor hiemalis, Alternaria alternata and Aspergillus niger are the fungal organisms isolated from the market and laboratory samples. The result of the total bacterial count (TBC, cfu/ml) show that the market samples displayed the highest TBC when compared with laboratory-prepared samples treated with natural spices, even better than the preservative chemical (sodium benzoate) treated samples. The cinnamon treated samples showed the lowest TBC values. The results confirmed that treating kulikuli with spices may reduce the effect of toxigenic organisms associated with this food product.