The antimicrobial activity of raw milkagainst Staphylococcus aureus, Salmonella enteritidis and Listeria. monocytogeneswas investigated. Populations of Staph. aureus and S. enteritidis in raw and pasteurised milkat 37°C increased from approximately104cfu/ml during the first 24-32 h of incubation to greater than 108cfu/ml, however, declined throughout theremainder of the experimental period in raw milk and to a lesser extent in pasteurised milk. Final populations of Staph.aureus and S. enteritidis after 72 h of incubation at 37°C were approximately 106cfu/ml and 107cfu/ml in pasteurised milkand 104cfu/ml and 105cfu/ml in raw milkrespectively. L. monocytogenes inoculated into raw milkat37°Cto give an initialbacterial concentration of approximately 104cfu/ml, multiplied at a reduced rate for approximately 12 h and then rapidlylost viability. Fifty-sixhours after the inoculation of raw milkno viable cells of L. monocytogenes were detectable. The pHof all treatment samples and controls declined to approximately 4.0 after 72 h of incubation at 37°C.
|Number of pages||4|
|Publication status||Published - 2000|