Premium
A study of the microbiological status of Irish farmhouse cheeses with emphasis on selected pathogenic and spoilage micro‐organisms
Author(s) -
Coveney Helen M.,
Fitzgerald G.F.,
Daly C.
Publication year - 1994
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.1365-2672.1994.tb02810.x
Subject(s) - pasteurization , food science , food spoilage , listeria monocytogenes , raw milk , biology , coagulase , microbiology and biotechnology , staphylococcus aureus , staphylococcus , bacteria , genetics
H.M. COVENEY, G.F. FITZGERALD AND C. DALY. 1994. Ninety‐six 25 g samples from 25 Irish farmhouse cheeses, two Irish non‐farmhouse cheeses and four foreign cheeses were evaluated for the presence of a variety of micro‐organisms, namely, coliforms, faecal streptococci, Staphylococcus aureus , yeasts, moulds, salmonellas and shigellas. Seventeen cheeses, i.e. the soft and semi‐soft types, were examined for Listeria monocytogenes. Most of the farmhouse cheeses are currently manufactured from raw milk, but some producers now use heat‐treated milk. The incidence of coliforms and faecal coliforms was higher in soft, semi‐soft and semi‐hard cheeses than in hard types. High levels of contamination by faecal streptococci and non‐pathogenic (coagulase‐negative) Staph. aureus prevailed in a high proportion of the cheeses. Pathogenic (coagulase‐positive) staphylococci, however, were also isolated from 50% of the cheeses, some of which were manufactured from pasteurized milk. Yeasts were found mainly in unpasteurized varieties, especially in the category of soft cheeses. Moulds were isolated from five non‐mould‐ripened cheeses, as well as from mould‐ripened varieties. Salmonellas, shigellas and Listeria monocytogenes were not detected after direct enrichment.