B02016: Microbiological risk factors associated with the domestic handling of meat

Study Duration: November 2000 to October 2003

Contractor: Campden and Chorleywood Food Research Association (CCFRA)

It is estimated that 11% of general outbreaks of food poisoning are associated with food prepared in the home for extended family or community events. Poultry and red meat are known carriers of food poisoning bacteria and are associated with a large proportion of these outbreaks.

While these bacteria will be killed if the meat is cooked properly, there is concern that some kitchen practices, such as washing poultry and other meats, actually increase the likelihood of people inadvertently contaminating kitchen sinks and preparation areas. Thereby increasing the risk of direct or indirect cross-contamination to other foods. It is particularly important to avoid cross-contamination from raw meat to foods, such as salads, which will not be cooked.

This project is seeking to provide information about the risks associated with preparing raw meat in the domestic kitchen. It will consider the effects of washing and soaking on the removal of micro-organisms from the surface of meat, the spread of contamination from meat washing practices, and the persistence of organisms that may have been spread by meat preparation practices. Interviews with consumers will help establish the extent to which people currently wash meat and what variations are used such as the length of soak time, water temperature and water additives, such as salt or vinegar. This research will help to inform future advice to the public.

Discussions on meat handling practices will be held with groups of consumers across the UK and these practices will be quantified by a consumer survey. Following on from the survey a kitchen study will be carried out in which consumers will prepare various recipes involving raw meats. Whilst preparing and cooking foods, their actions will observed and the spread of bacteria around the kitchen will be monitored after cooking by microbiological testing. Further laboratory studies will then be taken undertaken to assess how bacteria survives on typical kitchen surfaces.

The major findings of this project were:

• Twenty percent of consumers stored raw meat on the middle or top shelf of the fridge therefore increasing the risk of contamination of foods stored beneath. Many consumers were not aware of the correct fridge temperature and it is more than likely that some of the fridges were not running at the correct temperature, hence increasing the risk of multiplication of food poisoning bacteria. More than 60% of consumers were unaware that heating cooked food slowly could increase the risk of food poisoning or that cooling cooked foods quickly would reduce the risk of food poisoning.
• Washing of meat was reported to be a common practice among consumers (80% of consumers) and was carried out under a running tap. Many of those drying meat they had washed simply shook off the excess water. Washing and drying of meat in this manner creates splash and aerosols, which will result in indirect cross-contamination with microorganisms. Water splashed onto equipment and work surfaces, may promote the spreading of the bacteria from the meat. Washing and soaking studies did not decrease the bacterial level present on the surface of whole chickens or beef, therefore consumers that wash meat are not necessarily reducing the levels of bacteria, but are increasing the likelihood of contaminating surfaces and hands.
• The survey indicated that 14% of consumers had a board solely for raw meat. The majority of respondents did wash their boards after cutting meat, however 20% simply rinsed or wiped it with a cloth. A small percentage continued to use the board without washing, which could potentially lead to indirect cross-contamination of other foods such as read-to-eat salads or cooked foods.
• Many consumers washed disposable cloths, but over 30% of those that did not wash them kept them longer than 7 days before disposing of them. The moist environment of a damp dishcloth has ideal conditions for bacterial multiplication and there is enormous potential for the spread of bacteria when the cloth is in use.
• Pathogen survival studies indicated that high levels (10³cfu/4cm²) of salmonella and E. coli could survive for 48 hours on kitchen surfaces. High levels of bacteria were recovered by swabbing, which shows that pathogens can be easily removed. Contaminated surfaces are likely to cross-contaminate hands or prepared ready-to-eat foods placed on the contaminated surface.

This work has demonstrated that natural meat flora and pathogens that may be present on raw meat can be easily transferred to typical kitchen surfaces and that these organisms can survive for at least 48 hours. There are some areas of consumer knowledge that are lacking such as effective cleaning procedures for chopping boards, surfaces, knives and dishcloths, and the correct way to cool and re-heat foods. Consumers also need to be aware that there is a potential risk for bacteria to spread around the kitchen when meat is washed.

Final report is available from the FSA Library and Information centre. To obtain a copy, please contact the Enquiry Desk, Dr Elsie Widdowson Library and Information Services, Food Standards Agency ( 020 7276 8181/8182 or e-mail infocentre@foodstandards.gsi.gov.uk).

Contact: For any enquiries concerning this research project, please contact the relevant programme contact or e-mail science@foodstandards.gsi.gov