Samples of cabbage (Brassica oleracea) and lettuce (Lactuca sativa), commonly used for the preparation of vegetable salad were purchased from five locations in Uyo metropolis, Nigeria. These were analyzed microbiologically using standard methods before and after pre-treatment with different concentrations of vinegar and NaCl, respectively. Results obtained showed 1.2x107 cfu/g, 5.7x106 and 4.6x106 cfu/g of the total heterotrophic, coliform and fungal counts for fresh samples of cabbage, respectively. Mean counts of 1.4x107; 7.3x106 cfu/g and 5.0x106cfu/g were obtained for fresh lettuce (untreated) as total heterotrophic, total coliform and total fungal counts, respectively. However, pre-treatment with vinegar showed total mean heterotrophic, coliform and fungal counts of 5.2x103 cfu/g, 3.9x103cfu/g and 3.2x103 cfu/g for cabbage, while with NaCl, the counts were 4.9x103 cfu/g, 3.7x103 cfu/g and 3.2x103 cfu/g, respectively. Mean counts of heterotrophic, coliform and fungi for pre-treated lettuce showed 4.8x103, 3.4x103 and 3.5x103 cfu/g with vinegar and 4.7x103, 3.1x103 and 3.1x103 cfu/g, respectively with NaCl treatment. Statistical analysis using Analysis of Variance (ANOVA) revealed significant difference in microbial load (p=0.01) between fresh and pre-treated vegetables. Although there were variations in microbial loads of vegetables from different locations, the difference was not significant (p=0.05). However, levels of contamination differed significantly with concentrations of vinegar and NaCl. Organisms encountered included Bacillus sp, Pseudomonas sp, Staphylococcus aureus, Streptococcus sp, Escherichia coli, Serratia sp, Enterobacter sp, Citrobacter sp, Klebsiella sp, Shigella sp, and fungi such as Aspergillus flavus, Botrytis sp, Rhizopus sp, Fusarium sp, Saccharomyces cerevisiae and Candida tropicalis. Untreated vegetable harboured microorganisms above recommended and acceptable standard for ready-to-eat vegetables. The reduction of level of contamination achieved with pre-treatment with vinegar or NaCl suggests that these vegetables be washed in these solutions prior to preparation to ensure safety of consumers.
Vinegar, NaCl, Quality,Cabbage,Lettuce.