Survival and growth of Listeria monocytogenes in foods treated or supplemented with carrot juice
1995
Beuchat, L.R. | Doyle, M.P.
The influence of dipping shredded lettuce in carrot juice or adding carrot juice to Brie cheese and frankfurter homogenates on survival and growth of Listeria monocytogenes was studied. Viable populations were monitored over 14 days of incubation at 5, 12 or 20 degrees C. Aerobic mesophilic micro-organisms were also enumerated. L. monocytogenes grew at all incubation temperatures on lettuce not treated with carrot juice. Treatment with 20 or 50% carrot juice resulted in significantly (P < 0.05) lower populations of viable L. monocytogenes throughout the 14-day incubation period at 5 degrees C. Treatment retarded the growth of L. monocytogenes on lettuce incubated at 12 degrees C but was without affect at 20 degrees C. Increased amounts of carrot juice, from 0 to 2, 5 or 10%, resulted in significant reductions in viable cells of L. monocytogenes in Brie cheese incubated at PC but not at 12 or 20 degrees C. Carrot juice, when added at levels up to 10%, was ineffective in controlling the growth of L. monocytogenes in frankfurter homogenate, regardless of the incubation temperature. Treatment with carrot juice failed to influence growth of aerobic mesophilic micro-organisms in lettuce, cheese and frankfurter, indicating that microflora naturally present in these foods or in the carrot juice used to supplement them are resistant to antilisterial components in the juice.
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