Bacteria Colonization of Fresh Minimally Processed Fruits and Vegetables from Markets in Nsukka, Southeastern Nigeria

Abstract

Consumers’ demand for minimally processed fresh minimally fruits and vegetables owing to their reputation of being convenient, fresh, nutritive, healthy, and cheap has been on the increase over the years. Contamination of these commodities during processing has been reported and vendors often ignore proper hygienic processes. However, since fresh produce is often consumed raw, these products could harbor potentially pathogenic bacteria. In this study, 15 randomly selected samples of fresh, minimally processed watermelon, cucumber and garden egg were collected from markets in southeastern Nigeria and evaluated by way of standard plate techniques of serial dilution for bacterial contaminants. Following standard bacteriological practices, dilutions were plated on suitable growth media and incubated for 48 h. Pure cultures of bacterial isolates were investigated for total viable counts and identified both macroscopically and microscopically via Gram staining technique, spore staining technique, motility test and biochemical analysis. Fifty-eight isolates were obtained and the total viable plate count from all samples ranged from 1.0×106-8.0×106 CFU/g with watermelon samples recording the highest volume of bacteria loads. The cultural and biochemical characterization revealed the presence of seventeen (17) probable species of bacteria: Staphylococcus aureus (40%), Bacillus sp.(21%), Escherichia coli (18%), Staphylococcus epidermidis, Corynebacterium sp., and Citrobacter sp. (17%), Lactobacillus sp., and Proteus sp.(12%), Yersinia sp., Serratia marcescens, Listeria sp. and Pseudomonas sp.(6%),  Klebsiella sp., Streptococcus sp., Bacillus cereus and Clostridium sp. (5%), and Salmonella sp. (2%). Probable pathogenic bacteria exceeded the standard limit thus requiring urgent public sensitization and education by appropriate regulatory agencies. Therefore, the consumption of these minimally processed fruits and vegetables couldlead to foodborne infections.