Ad Hoc Group on Raw, Rare and Low Temperature Cooked Foods meeting, 3 October 2012

Summary of the second meeting of the Group

At this meeting the group received a presentation on the issue of bacterial behaviour and sous vide food safety and considered: data on the prevalence of pathogens in food served raw, rare or cooked at low temperature, data on the heat inactivation of foodborne pathogens and data on the disease burden in the community and outbreak data linked to raw, rare, low temperature cooked foods. The group also identified additional data they would like to consider.

Behaviour of pathogens at low temperature and the safety of sous vide food
The group were presented with the results of an FSA funded research project entitled ‘Bacterial behaviour and sous-vide food safety’. The project looked at the feasibility of extending Combase to describe the behaviour of E. coli, Salmonella and L. monocytogenes over the range 40-60°C and the most suitable modelling techniques to use. The group welcomed the findings, noted areas relevant to its work and highlighted issues that needed further consideration.

Data on the prevalence of pathogens in food served raw, rare or cooked at low temperature
The group considered the results of two LACORS (now LG Regulation) surveys of cooked burgers. It was noted that there were pathogens found in the burgers which were, in theory, served fully cooked. Members commented that there have been changes since the surveys were carried out, particularly with the move to give an option to serve burgers rare. It was suggested that there may have been more recent regional surveys that included these products and could provide some useful data. Members to be updated on the availability of recent data. It was added that the group may also receive an update on microbiological sampling study (study #43) coordinated by LG Regulation and the HPA concerning lightly cooked foods such as sous vide foods cooked by water bath, uncooked egg dishes, rare duck meat (pink duck), chicken parfait and pate made with flash fried liver. Its sampling dates were April – September 2011.

Data on the heat inactivation of foodborne pathogens
The group looked at data on the heat inactivation of foodborne pathogens. The information they considered showed that the increase in variation in the death of organisms due to meat type, fat content, water activity or strain type at low temperatures is a concern. It was highlighted that because this is complicated industry currently relies on 70°C for 2 minutes or 90°C for 10 minutes and any advice will have to avoid these complexities and provide a clear cut-off which would also be needed by Environmental Health Officers. The group discussed the issue of modelling growth in media and modelling death in media. The group considered the issue for sous vide chefs in relation to heat inactivation of foodborne pathogens and what their recommendations should cover. It was recognised that as sous vide has 4 steps – cooking, cooling, shelf life and regeneration, all of which carry a risk, the group should consider cooking, cooling and regeneration processes. The group identified a need for information on the highest growth temperature and lowest death temperature for vegetative pathogens and Clostridium perfringens.

Data on the disease burden in the community and outbreak data linked to undercooked foods
Following consideration of disease burden in the community and outbreaks linked to undercooked foods and the literature search on heat inactivation members indicated that they would like have to see heat inactivation data focused on Campylobacter as Campylobacter is currently on the rise.

Identify data gaps
The group discussed data gaps for possible future research. Members requested more information on the maximum growth temperatures and minimum death temperatures (at temperatures below 70°C) of the vegetative pathogens, Salmonella, Listeria, E. coli, Campylobacter, and Clostridium perfringens. Members also requested for the disease burden data expanded to include 2009 to the first 6 months of 2012 and an update on the LACORS survey on lightly cooked foods. In addition members raised the issue of whether there was information about cooling times at the end of cooking and if there were regulations that covered this.