Effects of Vinegar (5% Acetic Acid) Treatments On Reduction of Microbial Load On Lettuce

Abstract

Vegetable promotes good health but harbor a wide range of microbial contamination. This study was carried out to compare the effectiveness of two commercially available vinegars labeled as (X and Y) at different concentration in decontamination of lettuce sold in Ahmadu Bello University, Zaria. Thirty (30) samples of lettuce vegetable were purchased from two different sell points in the University. The samples were analyzed using standard bacteriological method to enumerate total aerobic plate count before and after washing with vinegars at different concentrations. In addition Minimum Inhibition Concentration (MIC) was used to measure zone of bacterial inhibition. The result showed that the mean total aerobic plate count of 5.64 log₁₀ cfu/g before washing with vinegar. After treatment with vinegar X the mean counts were 3.79, 4.95, and 5.28 log₁₀ cfu/g for different concentration 1:1, 1:2 and 1:3 respectively. While after treatment with vinegar Y the mean total aerobic plate counts were 4.09, 5.27, and 5.39 log₁₀ cfu/g at different concentration 1:1, 1:2, and 1:3 respectively. Two genera of bacteria were isolated with the percentage isolation rate of 22 (75%) for proteus and Eschericia coli 8 (25%). From the MIC mean zone of inhibition of 16.6mm and 13.4mm for the stock solution X and Y respectively were recorded showing a slight difference compared to one obtained after treating the lettuce with higher concentration above the manufacturers recommended concentration. The use of vinegar in washing fruits and vegetable using the appropriate concentration is recommended as shown by the result.