INHIBITION OF LISTERIA-MONOCYTOGENES, SALMONELLA-TYPHIMURIUM AND ESCHERICHIA-COLI O157-H7 ON BEEF MUSCLE-TISSUE BY LACTIC OR ACETIC-ACID CONTAINED IN CALCIUM ALGINATE GELS

A method of applying organic acids contained in a calcium alginate gel was tested for inhibiting bacteria contaminating sterile lean beef tissue surfaces. Treated samples were incubated at 5C under controlled moisture conditions for up to 7 days and viable populations of the pathogens determined. For counts of L. monocytogenes, recovered on tryptic soy agar, alginate/lactic acid treatment reduced the log10 counts 1.8 units vs 0.96 for acid treatment without alginate. With acetic acid, log10 reductions were 1.51 vs 2.33 for the alginate/acetic acid vs acetic acid treatment alone. S. typhimurium was reduced 2.11 log10 units vs 1.11 for alginate/lactic acid and acid treatments alone, respectively. The same trend held for E. coli O157:H7, although the reduction was considerably less, 0.74 log10 reduction vs 0.5 for alginate/lactic acid application vs acid alone. Both Gram-negative organisms were less inhibited by acetic acid treatments.