ANTILISTERIAL ACTIVITY OF SODIUM, POTASSIUM OR CALCIUM LACTATE IN PORK LIVER SAUSAGE

Abstract

ABSTRACT The antilisterial activity of sodium, potassium or calcium lactate was tested in pork liver sausage (55% moisture, 2% sodium chloride). Lactate levels of 2, 3 or 4% (w/w) were used and the sausage was sterilized and inoculated with 104–105 cells/g of Listeria monocytogenes strain Scott A. Enhanced inhibitory effects of the organism were observed with increasing concentrations of the salts at two storage temperatures. At 20C, cell numbers in the controls increased by 5 log cycles after 10 days. The change in log CFU/g in samples treated with 4% of the lactate salts was: sodium, 1.4; potassium, 1.35, and calcium, ‐1.33. At 5C, cell numbers after 50 days of storage increased by 4.5 log cycles in controls, and changes in log CFU/g in samples treated with 3% lactate were: sodium, 0.88; potassium, ‐0.67, and calcium, ‐1.49. Increasing the sodium chloride content in the product enhanced the inhibitory effects. While L. monocytogenes grew better in heat processed (water bath) than in heat sterilized sausage, cell growth was suppressed during refrigerated storage by 3% of each of the lactate salts, and the effect of the calcium salt was superior to that of either the sodium or the potassium salt. Although addition of lactates to the sausage lowered the water activity, the change was not sufficient to account for the antilisterial activity of these salts.