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Occurrence of Listeria species in raw milk and dairy products produced in Northern Ireland
Author(s) -
Harvey J.,
Gilmour A.
Publication year - 1992
Publication title -
journal of applied bacteriology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.889
H-Index - 156
eISSN - 1365-2672
pISSN - 0021-8847
DOI - 10.1111/j.1365-2672.1992.tb01812.x
Subject(s) - listeria monocytogenes , listeria , raw milk , agar , biology , pasteurization , food science , microbiology and biotechnology , typing , isolation (microbiology) , agar plate , bacteria , veterinary medicine , medicine , genetics
J. HARVEY AND A. GILMOUR. 1992. The overall incidence of Listeria spp. in raw milk samples surveyed was found to be 25.0% ( Listeria monocytogenes 15.3%), with the incidence in samples from processing centres 54.0% ( L. monocytogenes 33.3%); this was higher than that in samples from dairy farms ( Listeria spp. 8.8% L. monocytogenes 5.3%). The FDA enrichment procedure was much more productive than cold enrichment and Oxford agar was superior to modified McBride agar for isolation of Listeria. Listeria monocytogenes was never isolated by direct plating of raw milk samples on Oxford agar at a detection level of 1.0 cfu/ml. Listeria spp. were isolated from 1 of 95 pasteurized milk samples ( L. monocytogenes ) and 1 of 33 soft cheese samples ( L. seeligeri ). Restriction fragment length polymorphism was more useful than sero‐ or phage‐typing for typing of L. monocytogenes strains, and results suggest that specific L. monocytogenes strains may persist in both farm and processing environments.