Evaluation of the Microbial Load and pH of Pap Produced from Selected Cereals

Abstract

The aim of this work was to evaluate the microbial load of pap samples made from three commonly utilized cereal grains namely: maize (Zea mays), millet (Pennisetum typhoideum) and guinea corn (Sorghum bicolor). Exactly 2 kg each of the aforementioned grains was steeped in 1000 ml of clean water for 3 days at 30±20C temperature. The water was disposed and the cereal grain separately washed thoroughly using clean water. The grains were then wet milled and the resulting paste mixed with1000 ml of clean water. The slurry was filtered with the aid of the muslin cloth. The filtrate was then allowed to stand for a period of 24 hours and the supernatant disposed. Microbiological analysis to determine microbial load on the various samples were carried using standard procedures. Guinea corn based pap had the highest lactic acid bacteria count of 9×103 CFU/g at 0 hr of fermentation which decreased to 6.6×105 CFU/g at the 72nd hr.  On the other hand, the composite of the three cereals had the lactic acid bacteria count of 4.2×104 CFU/g at 0 hr of fermentation which increased to 8.6×105 CFU/g at the 72nd hr, the highest value recorded for all samples studied. Total coliform count on all samples maintained a uniform trend of increase at the 24th and 48th hr and a decrease at the 72nd hr. Millet based pap had the highest fungi count of 2.3×101CFU/g at 0hr of fermentation which increased progressively to 4.9×101 at the 72nd hr. However, pap derived from the composite of the cereals presented the lowest fungi count of 0.52×102   at 0hr which however increased progressively to record the highest count of 1.4×101at the 72nd hr. In conclusion, there is need to optimize the growth of lactic acid bacteria in the production of pap, this may enhance its acid production potential and consequent inhibition and/destruction of potential harmful microorganisms in fermented foods.