Survival of foodborne bacteria on strawberries and antibacterial activities of hibiscus sabdariffa extracts and chemical sanitizers on strawberries.

The potential of 13 foodborne bacteria to attach and survival on strawberries and the antimicrobial activities of Hibiscus sabdariffa calyx extracts and chemical sanitizers against foodborne bacteria on strawberries were investigated. Strawberries were inoculated with thirteen foodborne bacteria: Listeria monocytogenes, Shigella flexneri, Staphylococcus aureus, Salmonella Typhimurium, S. Typhi, S. Montevideo, Vibrio cholerae O1, and six pathotypes of Escherichia coli: O157:H7, Non-O157:H7-Shiga toxin-producing, enteropathogenic, enterotoxigenic, enteroinvasive, and enteroaggregative. The antibacterial effects of four roselle calyx extracts (in water, methanol, acetone, and ethyl acetate), sodium hypochlorite, colloidal silver, and acetic acid against all pathogenic bacteria were evaluated on contaminated strawberries. All foodborne bacteria attached and survived on strawberries at least 15 days. Acetonic and methanolic roselle calyx extracts caused a greater reduction in the concentration (until 3.8-log10 reduction in some cases) of all foodborne bacteria than the sodium hypochlorite, colloidal silver and acetic acid on contaminated strawberries.