T7-05 Risk Assessment of Escherichia coli O157 in Burgers Made from Australian Beef Trim

Tuesday, July 30, 2013: 2:30 PM
213BC (Charlotte Convention Center)
Andreas Kiermeier, SA Research & Development Institute, Adelaide, Australia
John Sumner, Meat & Livestock Australia, North Sydney, Australia
Ian Jenson, Meat & Livestock Australia, North Sydney, Australia
Introduction: Escherichia coli O157 is an enteric pathogen which can result in serious illness. Cattle are a known reservoir for this organism and there is potential that meat can become contaminated during slaughter. For this reason, all beef trim destined for grinding in the US has to be sampled and tested using the “robust” N-60 sampling program.

Purpose: Australia is a major supplier of manufacturing meat intended for grinding in the USA and the purpose of this study was to assess the risk posed by E. coli O157 from the consumption of burgers made only from Australian beef trim and to compare the effects of sampling and cooking interventions on illness estimates.

Methods: A quantitative risk assessment model was developed for E. coli O157. Lots of 700 cartons, each 27.2 kg, were modeled from the time the beef trim was packed into cartons through to consumption as 100 g burgers. The number of illnesses from burgers consumed was calculated for each of the following scenarios: cooking at home (to variable internal temperature), cooking by a quick service restaurant to internal temperature of 68°C, and sampling of raw beef trim using various sampling plans in combination with home-cooked burgers.

Results: Using only Australian beef, burgers cooked and consumed at home resulted in 3.0 illnesses per 10,000,000 burgers while from quick service restaurants the rate was 7.3 illnesses per 100,000,000,000 burgers consumed. By contrast, sampling of raw beef trim prior to grinding reduced the illness rate to 1.5 per 10,000,000 burgers consumed under N-60 sampling. This rate dropped further to 1.1 per 10,000,000 when N-60 is doubled to N-120.

Significance: In this risk assessment the rate of illness from burger consumption was modeled for 700 × 27.2 kg carton lots of beef trim. The results of this work show that the rate of illness from the consumption of burgers made only from Australian beef trim are low. In addition, the results confirm the lack of effectiveness of sampling beef trim for E. coli O157 relative to thorough cooking of burgers.