Comparative Bacteriological Quality of Retail Roast Meat Products in Parts of Kaduna and Zaria Towns, Nigeria

Abstract

Bacillus cereus is an opportunistic pathogen of humans, and a frequent cause of food poisoning. Widely distributed in the environment,  it is easily spread to many types of foods and has been referred to as the major problem in convenience foods and mass catering owing to its spore forming ability. This study compared the bacteriological quality of 3 street-vended roast meat products of northern Nigeria- suya (spiced roast meat), balangu (unspiced roast meat), and soye (hawked spiced roast meat) in some parts of Kaduna and Zaria towns of Nigeria, particularly as it relates to their quantitative bacteriological quality, and to the presence of B.cereus. A total of 129 samples comprising 43 samples each of Suya, Balangu and Soye were subjected to 10 fold serial dilutions and plated onto sterile plates of Nutrient agar and Mannitol Egg-yolk Polymyxin Agar (MYP) for Total Aerobic Plate Count (TAPC) and B.cereus isolation respectively. Presumptive B.cereus colonies were identified biochemically using a Microgen^TM Bacillus ID. Mean TAPC was highest for soye (6.3±1.0log₁₀ cfu/g) and lowest for suya (3.9±0.9log₁₀ cfu/g). Similarly, mean B.cereus counts was highest for soye (2.4±0.3log₁₀cfu/g), and lowest for suya (1.4±0.3log₁₀ cfu/g). Frequency of occurrence of B.cereus was  highest for balangu at 7 (16%) and lowest for Soye at 3 (7%). There were no significant differences in B. cereus count and TAPC amongst samples of the same product at 5% level (P>0.05). Study revealed TAPC and B.cereus counts being at levels considered satisfactory and marginal for suya and balangu respectively at the point of sale but unsatisfactory  for Soye. The study highlights the need for regulatory agencies to educate Soye vendors on the implications of the use of substandard practices in the handling and sale of the product, and also guide consumers in their choices of vended roast meat products.