G. Holds

A baseline survey of the microbiological quality of chicken portions and carcasses at retail in two Australian states (2005 to 2006).

Raw poultry products were purchased from the retail market place in two Australian states, New South Wales (n = 549) and South Australia (n = 310). The products sampled on a proportional volume basis were chicken portions with the skin off or skin on, in bulk or tray packs, and whole carcasses. They were collected from butcher shops, supermarkets, and specialty stores from urban areas during the winter (2005) and summer (2006) months. The samples were analyzed to determine the prevalence and concentration of Escherichia coli, Salmonella, and Campylobacter spp. in addition to total viable counts. Salmonella was found in 47.7 and 35.5% of retail chicken samples (35.3 and 21.9% were the less virulent Salmonella Sofia), at mean counts of -1.42 and -1.6 log MPN/cm2 in New South Wales and South Australia, respectively. Campylobacter was found in 87.8 and 93.2% of samples at mean counts of 0.87 and 0.78 log CFU/cm2, respectively. In both states in both seasons, the mean total viable count was 5 log CFU/cm2. On whole birds, E. coli was detected in all winter samples and on 92.9 and 85.7% of summer samples in New South Wales and South Australia, respectively; the log of the geometric mean per square centimeter was 0.5 in winter and slightly lower in summer. On chicken portions, E. coli was detected in around 90% of winter samples in both states, and in summer on 75.1 and 59.6% of samples in New South Wales and South Australia, respectively. The log of the geometric mean CFU per square centimeter for E. coli was 0.75 and 0.91 in winter, and 0.66 and 0.5 in summer in New South Wales and South Australia, respectively.

Slaughterfloor Decontamination of Pork Carcases with Hot Water or Acidified Sodium Chlorite – A Comparison in Two Australian Abattoirs

A decontamination trial on the effectiveness of hot water or acidified sodium chlorite (SANOVA™) treatment on Salmonella spp., Escherichia coli and Total Viable Count (TVC) was undertaken on pork carcases prior to primary chilling in two large pork abattoirs in Australia using belly‐strip excision sampling. A total of 123 samples from Abattoir A and 400 samples from Abattoir B were cultured and analysed. Test pigs were selected from herds with a known high level of on‐farm Salmonella infection. At Abattoir A, Salmonella spp. were not isolated from carcases. The prevalence of E. coli on control carcases was 92.9% compared with 9.8% for hot water and 12.5% for SANOVA™ treated carcases. The mean log10E. coli concentration for control carcases was 0.89 cfu/gram, compared with −0.83 cfu/gram from hot water and −0.75 cfu/gram from SANOVA™ treated carcases. The mean log10 TVC for control carcases was 4.06 compared with 1.81 cfu/gram for hot water and 2.76 cfu/gram for SANOVA™ treated carcases. At Abattoir B, the prevalence of Salmonella on control carcases was 16% compared with 2.7% for hot water and 7.0% for SANOVA™ treated carcases. The prevalence of E. coli on control carcases was 69.3% compared with 22% for hot water and 30% for SANOVA™ treated carcases. The mean log10E. coli concentration for control carcases was 0.45 cfu/gram, compared with −0.65 cfu/gram from hot water and −0.60 cfu/gram from SANOVA™ treated carcases. The mean log10 TVC for control carcases was 3.00 cfu/gram compared with 2.10 cfu/gram for hot water and 2.53 cfu/gram for SANOVA™ treated carcases. The reductions in prevalence and mean log10 concentrations in the present trial were all found to be statistically significant and indicate that carcases decontamination with either hot water or SANOVA™ are effective risk management options immediately available to the pork industry.

The adequacy of sample type/weight and incubation period on detection of Salmonella spp. in slaughter cattle

The purpose of this study was to examine the adequacy of different sample types (fecal and rumen content), rumen-content sample weight (1, 10, and 25 g), and incubation period on the detection of Salmonella spp. in grass-fed beef cattle at slaughter. The culture technique was the same for all samples and followed the Australian Standard (AS 1766.2.5—1991). Sample adequacy was defined as the ratio between the overall prevalence, as obtained from samples identified as positive by any sample type/weight, and the estimated prevalence, as obtained from samples identified as positive by a particular sample type/weight. Sample adequacy reflects the likelihood of a sample of a particular type and weight to contain the organism of interest and hence is related to the sensitivity of the diagnostic test. It was found that sample adequacy differed between sample types and weights: 37.5% for both a 10-g fecal sample and a 1-g rumen sample, 77.1% for a 10-g rumen sample, and 79.2% for a 25-g rumen sample. On this basis, it is strongly recommended that sample type and weight be considered in the design of studies that aim to quantify Salmonella contamination in cattle.