EFFICACY OF HIGH SODIUM-CHLORIDE CONCENTRATIONS FOR THE DESTRUCTION OF LISTERIA-MONOCYTOGENES

The effect of sodium chloride concentrations (6, 16 and 26% (w/v) NaCl) on the survival of Listeria monocytogenes at low temperatures (10-degrees-C and under refrigeration, average 2-degrees-C) and frozen (-18-degrees-C) was investigated. All salt concentrations tested were ineffective in reducing numbers over 6 h incubation at low temperatures. Over a longer time (33 d) at low temperatures, the organism grew in 6% NaCl, numbers remained the same in 16% NaCl and numbers declined in 26% NaCl. Although L. monocytogenes was destroyed in 26% NaCl, numbers declined too slowly for immersion in cold brine at this concentration to be a useful bacteriocidal treatment. Storage at - 18-degrees-C for 33 d caused no significant reduction in numbers at any of the NaCl concentrations tested.