Microbiological quality of Australian sheep meat in 2011

The fourth national baseline microbiological survey of Australian sheep meat was conducted in 2011 including for the first time samples from selected sheep meat primal cuts. Sheep and lamb legs (n = 613) and shoulders (n = 613) sampled at 12 meat processing establishments were found to have mean total viable counts (TVC, 25 °C) of 2.02 and 2.29 log10 cfu/cm2 respectively; Escherichia coli was isolated from 42.9% of legs and 34.6% of shoulders with respective mean counts of −0.44 and −0.63 log10 cfu/cm2 on positive samples. For samples of frozen boneless sheep meat (n = 551) the mean TVC was 2.80 log10 cfu/g and the mean count for the 12.5% of samples with detectable E. coli was 1.51 log10 cfu/g. Presence of E. coli O157:H7 was not assessed in any of the frozen boneless product but the pathogen was isolated from 2/613 leg and 1/613 shoulder samples. Salmonella was isolated from 17/613 leg samples, 5/613 shoulders and from 17/551 samples of frozen boneless product. Campylobacter spp. were isolated from 1/613 shoulder samples but presence was not tested in any of the frozen boneless samples. Listeria spp. were not detected in any of the frozen boneless product and was isolated from 1/613 leg samples. Coagulase-positive staphylococci were isolated from 4.2%, 5.2% and 1.8% of leg, shoulder and frozen boneless sheep meat samples, respectively with positive samples having a mean log10 count of −0.21 cfu/cm2, 0.34 cfu/cm2 and 1.66 cfu/g respectively. It is concluded that, in the present survey, extreme weather patterns led to elevated levels of indicator organisms (aerobic plate counts and E. coli prevalence) on frozen trim compared with previous Australian baseline surveys.