Microbiological Assessment of Ready-to-Eat Foods (RTEs) for the Presence Bacillus species

Abstract

This study aimed to microbiologically assess some ready-to-eat (RTE) foods for presence of Bacillus species. Hygienic conditions of the food vending sites were also considered. Samples were purchased from nine sale points. Sixty ready-to-eat (RTE) food samples (Buns, Meat pie, Egg roll, White rice, Jollof rice and Fried rice) were randomly purchased from cafeteria, canteens and various food vending sites within and around the institution. Immediate microbiological analysis was carried out to assess the microbiological quality of the foods using general purpose (Nutrient agar) for total viable counts, and selective/differential isolation media (HiCrome Bacillus agar - HiMedia) for assessment of Bacillus species. Bacteria isolated with percentage occurrence include Bacillus cereus (11.26%), Bacillus subtilis (21.85%), B. megaterium (24.59%) and B. thuringiensis (25.83%). Other bacilli such as Bacillus stearothermophilus, B. licheniformis, B. amyloliquefasciens, B. mycoides, B. brevis, B. polymyxa and B. laterosporus constituted 16.56%. Total viable count (TVC) varied significantly among samples, especially with the buns (134.00±0.10) samples in week six. Similar observation was made for differential bacilli count at week 6 (62.00±0.04). TVCs for samples were observed to be within the satisfactory and marginal range for standard plate count (SPC); while differential Bacillus counts were observed within the marginal to unsatisfactory range. No matter how seemingly clean or unkempt the preparatory environment for thee foods, Bacillus species were still present at all sample sites. The research reiterated that ready-to-eat foods (RTEs) rarely meet microbiological standards for quality.