INHIBITION OF LISTERIA-MONOCYTOGENES IN COLD-PROCESS (SMOKED) SALMON BY SODIUM LACTATE

Comminuted raw salmon containing various concentrations and combinations of sodium lactate, sodium chloride, and sodium nitrite was inoculated with 10 Listeria monocytogenes cells per g (150 cells/l5-g sample), vacuum-packaged in oxygen-impermeable film and stored at 5 or 10 degrees C. Samples were examined for growth of L. monocytogenes and total aerobic microorganisms at specific intervals for up to 50 d. Sodium lactate exhibited a concentration-dependent antilisterial effect that was enhanced by nitrite and/or increased concentrations of NaCl. At 5 degrees C, total inhibition of L. monocytogenes was achieved for up to 50 d by 2% sodium lactate in combination with 3% water-phase NaCl. At 10 degrees C, total inhibition was achieved for up to 35 d by 3% sodium lactate in combination with 3% water-phase NaCl, or by 2% sodium lactate in combination with 125 ppm sodium nitrite and 3% water-phase NaCl. Sodium lactate and the other additives also inhibited growth of the aerobic microflora but to a lesser degree than L. monocytogenes.