ABSTRACT

Locally produced soymilk was subjected to microbiological analysis (under two storage conditions - ambient and refrigeration) to ascertain their hygienic standard of production and the shelf life. Standard Microbiological techniques, Pour Plate method were used in the enumeration of potential spoilage organism in soymilk sample. Result of microbial analysis showed that activities of microorganisms were more pronounced in the sample kept at ambient temperature (27°C) with bacterial count of 2 X 10³on the first day after production and increased to 2.9 X 10 after six days of storage. There was outstanding difference in the bacterial count of the refrigerated sample as none was observed in the first day after production but later increased to 1.5 X 10⁴after the sixth day. Results obtained showed that soymilk can be kept for up to three (3) days at refrigeration temperature (4°C). Seven bacterial isolates, Bacillus spp, Lactohacillus spp, Streptococcus spp, Saphylococcus aurcus, Micrococcus spp, Enterobacter spp and Escherichia coli and three fungal isolates, Aspergillus spp, Rhizopus spp, and Penicilliurn spp were detected in the soymilk stored at both ambient and refrigeration conditions. The microbial population detected in terms of' number and types of microorganisms reflected poor hygienic standard of production, constituting a public health hazard among the consumers. The result of statistical analysis carried out revealed that there was significant treatment effect on the growth of microorganism. The type of growth media and storage condition affected growth of microorganism. The implication of this study is that the quality of locally produced soymilk needs to be critically monitored to avoid transmission of infection to consumers. It is also very necessary that local producers should be enlightened about good manufacturing practices and the effect of proper storage as this will ensure products free of pathogenic microorganisms.