Effectiveness of Varying Concentrations of Salt and Vinegar against the Bacterial Contaminants of Fruits and Vegetables

Abstract

Fruits and vegetables, which are of human diets, are regularly tainted by various microbes. Microbial contamination can arise from various causes such as environment, animals,  human activity, through transportation or preparation of produce from the farm to the table. The purpose of this study was to evaluate the effects of different vinegar and salt concentrations on the bacterial loads of several fruits and vegetables that are sold in the city of Gombe. For the evaluation, a total of thirty fruits and vegetables from various suppliers were used. A portion of each sample was subjected to a ten-fold serial dilution prior to treatment with either of the two agents. Aliquots of the 10^-1, 10^-2, and 10^-3 dilutions were then inoculated using the pour-plate technique on nutrient agar and MacConkey agar plates. The plates were incubated at 37°C for 24 hours during which the counts of aerobic mesophilic and faecal coliform were observed. Results of the bacterial loads observed prior to washing ranged from 3.7x10⁴ to 2.7x10⁵ and 2.9x10⁴ to 8.7x10⁴ for total mesophilic and faecal coliform count, respectively; however, a significant decrease of the bacterial loads of up to 0.77-1.91 and 0.50-1.23 log was observed following treatment with vinegar and salt solutions, respectively. It was concluded that vinegar was significantly more effective than salt in reducing the bacterial loads of the fruits and vegetables (P<0.05). In summary, the fruits and vegetables were found to be contaminated with high bacterial loads that decreased with increased concentrations as well as the exposure time of the vinegar and salt solutions.