Factors contributing to the microbiological contamination of beef carcases

Summary

​There are many factors that can affect the microbiological quality of carcases including:

the cleanliness of cattle
how stressed the cattle are
the procedures used for removing the hide
evisceration
dressing
chilling
In Australia, where all export registered establishments meet the requirements of the Australian Standard and the Export Meat Orders and are supervised by the same controlling authority, there are large differences between the microbiological quality, as measured by the E. coli and Salmonella monitoring program - ESAM, of carcases at one abattoir compared to another.

This project was undertaken to determine why some establishments consistently have low E. coli prevalence in their ESAM testing while others have higher prevalence.

Fifteen plants agreed to participate in the project, each was visited by researchers and supplied answers to a questionnaire which asked about:

livestock slaughtered
slaughter and dressing technique
chain speeds
staff training and turnover
The researchers attempted to find groupings of plants, based on problem and process factors, to help plants understand why they have a higher or lower E. coli prevalence than others.

The factors thought to be most important were the:

proportion of feedlot stock
length of transport
degree of hide contamination or tag
proportion of cows/bulls processed
The factors used to group the plants suggest that these factors may have some influence on the E. coli prevalence and therefore the hygienic quality of carcases produced.

This project does not prove that the selected factors have a direct effect on E. coli prevalence.

Further investigations are required before any conclusions can be drawn about how to reduce the prevalence of E. coli on carcases.