Control of growth and survival of Listeria monocytogenes on smoked salmon by combined potassium lactate and sodium diacetate and freezing stress during refrigeration and frozen storage.

摘要

Antimicrobial effects of various levels of a mixture containing potassium lactate and sodium diacetate (PL+SDA), against the growth and survival of Listeria monocytogenes Scott A inoculated onto smoked salmon stored at 4, 10 or -20degC, were evaluated. In addition, effects of freezing stress upon the growth kinetics of L. monocytogenes Scott A on smoked salmon at 4 and 10degC were also investigated. Use of PL+ SDA at all tested levels (1.5, 3.3 and 5% of a 60% commercial solution of PURASAL P Opti.Form 4) completely inhibited the growth of L. monocytogenes Scott A on smoked salmon stored at 4degC during 32 days of storage. It also delayed the growth of L. monocytogenes Scott A on smoked salmon stored at 10degC for 11 days, but a listeriostatic effect was observed only with 5% PURASAL P Opti.Form 4 at 10degC after 11 days. Addition of PL+SDA at all tested levels decreased the surviving populations of L. monocytogenes Scott A on smoked salmon during 10 months of frozen storage at -20degC. Freezing stress significantly extended the lag time and delayed the growth of L. monocytogenes Scott A at both 4 and 10degC (P < 0.001). The effect of freezing stress was more marked at 4degC than at 10degC, however, indicating the importance of smoked salmon temp. control during retail storage.