Potential of acidified sodium benzoate as an alternative wash solution of cherry tomatoes: Changes of quality, background microbes, and inoculated pathogens during storage at 4 and 21°C post-washing

Abstract

To evaluate the feasibility of acidified sodium benzoate (NaB) as alternative washing solutions of fresh produce, the survival of inoculated pathogens, the background molds and yeasts counts, and quality parameters were compared during 4 and 21 °C storage of cherry tomatoes washed with 3000 ppm NaB at pH 2.0, 200 ppm free chlorine at pH 6.5, water adjusted to pH 2.0, and distilled water. The acidified NaB solution was the most effective in reducing the population of Escherichia coli O157:H7, Salmonella enterica and Listeria monocytogenes cocktails on tomatoes (>4 log CFU/g). NaB was more effective than free chlorine (P < 0.05) in reducing the two Gram-negative bacteria on tomatoes, while the reduction of Gram-positive L. monocytogenes by NaB (5.49 log CFU/g) and chlorine (4.98 log CFU/g) was similar (P > 0.05). No recovery of bacteria was found in all treatments during storage for 15 days. The acidified NaB effectively controlled yeasts and molds on cherry tomatoes to <1 log CFU/g or below the detection limit at both temperatures during 15-d storage, while free chlorine did not. Compared to unwashed controls, NaB had no effect on color, weight loss, firmness, and total soluble solids content of tomatoes during storage. The effect of NaB reducing pathogenic and spoilage microorganisms on tomatoes and maintaining quality during storage suggests its potential as an alternative wash solution in postharvest processing of fresh produce.