Assessment of Sodium Hypochlorite and Acidified Sodium Chlorite as Antimicrobial Agents to Inhibit Growth of Escherichia coli O157:H7 and Natural Microflora on Shredded Carrots

Abstract

Acidified sodium chlorite (ASC) is an alternative to chlorine in reducing microbial populations to maintain food quality and safety on fresh-cut produce. However the most effective concentration for microbial reduction on shredded carrots is unknown. In this study the influence of tap water, sodium hypochlorite (SH; 200 mg · L-1) and acidified sodium chlorite (ASC; 100,250,500 and 1,000 mg·L-1) washes on natural microflora, and survival and growth of Escherichia coli O157:H7 inoculated onto shredded carrots, was determined after treat-ment and 7 and 14 days of storage. The carrots were stored under passive modified atmosphere at 5°C. While a tap water wash did not reduce growth of E. coli O157:H7, total plate count or yeast and molds, spoilage and pathogenic microorganisms were reduced by two logs by using SH or ASC at 200 and 100 mg·L-1, respectively. ASC at concentrations above 100 mg·L-1 was very effective in reducing microbial growth by 6 logs. During storage, total mesophilic growth increased in samples washed with tap water, SH or ASC at 100 and 250 mg·L-1. However, shredded carrots washed with ASC at 1000 mg·L-1 did not show any microbial growth even after 14 days of storage at 5°C.