Scientists dismiss changes to rare burger advice
The FSA’s Advisory Committee on the Microbiological Safety of Food (ACMSF) has restated its advice that to avoid the risk of food poisoning from pathogens such as Shigatoxin producing Escheria coli (STEC)O157, burgers should be cooked for two minutes (2 mins) at 70°C to ensure any bacteria present at their core is killed off.
The FSA has come under increasing pressure to produce new safety advice for restaurants, local authorities and consumers as the trend for serving burgers less than thoroughly cooked in foodservice outlets has grown in recent years.
“There is now an emerging interest in pink burgers,” said Dr Michael Burton, research fellow in the School of Social Sciences at the University of Manchester, speaking at the Chartered Institute of Environmental Health annual food safety conference in London last month.
Burton described the unpublished research results of a survey on beef burgers, which showed differences in the visual perception of the safety of burgers cooked well and rare between consumers, environmental health officers and chefs.
Rare burger perception
It showed a small, but significant number of the public think rare burgers met FSA safety guidelines. “A small group of customers want them pinker than chefs expect,” said Burton.
The ACMSF was asked by the FSA board to assess whether any “interventions” – such as lactic acid treatment or steam pasteurisation of carcasses – combined with different time-temperature cooking combinations could be used to reduce the levels of STEC 0157 and thus reduce the risk of burgers served less than thoroughly cooked in restaurants.
The ACMSF members congratulated food manufacturers and retailers on the work they had done to ensure that when cooked properly, burgers were safe to eat. This had been achieved by improving the uniformity of burgers and by using systems that prevented cross-contamination of burgers in the supply chain.
However, the they were unanimously of the opinion that the variables in pre-treatment, size, composition and shape of burgers, and cooking conditions, meant that the only way to ensure safe burgers in restaurants was to retain the 70°C for 2 mins recommendation.
Recontamination danger
Dr Roy Betts*, head of food microbiology at Campden BRI, said: “Source reduction [of STEC O157] only works if you can maintain that level of reduction throughout … if you do not control the carcass and prevent recontamination, then you lose what you have gained and [steam pasteurisation] becomes a control step after which you have to handle it differently. If you don’t it will recontaminate.”
Dr Gary Barker, a senior research scientist at the Institute of Food Research, added: “There is a huge variability in the way people cook and we have massive uncertainties when we combine different processes.”
The FSA board are scheduled to discuss the development of a framework for the assessment of foods which might present an increased likelihood of harm at its next meeting on July 13. At this meeting the board will also receive an update on burgers served less than thoroughly cooked in foodservice outlets.
Members were particularly worried that the tendency in restaurants for serving extra-large (gourmet), ‘non-flat’ burgers rare would increase the likelihood of dangerous pathogens to survive and cause food poisoning.
Dangers in the home
Dr Jo Head, a meat processing food safety expert and an observer present at last week’s ACMSF meeting, also raised the concern – also expressed by others – that one of the biggest dangers would be if consumers, seeing burgers served widely served in restaurants, mistakenly thought they could do the same at home.
The fear is that consumers could be confused and mislead into thinking they make rare burgers using minced beef and other meats bought from supermarkets that had not been through the same strict hygienic process control and preparation measures to reduce the presence of dangerous pathogens. The consequences for food safety in the home could be potentially catastrophic, they suggested.
* Betts will be giving a presentation on ‘Advances in microbial detection’ at Food Manufacture's food safety conference ‘Boosting consumer confidence in times of change’ in London on October 13. He will outline how whole genome sequencing and meta-genomics are rapidly replacing traditional laboratory techniques for identifying dangerous pathogens. His presentation will describe the latest analytical approaches to detect emerging threats.
