Contents: Surveillance of foodborne disease | Phasing out ethylene oxide | Campylobacter in cattle and sheep | Campylobacter (and others) in the kitchen | The Food Safety ToolKit™
Campylobacter (and others) in the kitchen
It is clear from the above report from Communicable Diseases Intelligence that Campylobacter spp. are major causes of concern with regard to gastrointestinal disease including that which is foodborne.
It is noted that there was only the one outbreak of campylobacteriosis included amongst the number of incidents meaning that most of those reported were sporadic and probably involved only one person or a few people. Since number of cases reported is likely to be a small percentage total cases, it is not surprising that estimates of total numbers of foodborne illness annually in this country vary widely. Infection with enteric campylobacters usually leads to diarrhea and severe cramping. It occurs most frequently in young children and young adults. Initial symptoms are usually followed by abdominal pain and general malaise. The disease is usually limited to 5-8 days but an association exists with certain long-term neurological symptoms and Guillain Barré Syndrome (Journal of Applied Microbiology 90 2001 45S).
Campylobacters are considered to be part of the normal intestinal flora of a wide range of domestic and wild animals. Faecal contamination of meat occurs during slaughter and subsequent operations and human infection is usually through consumption of undercooked meat or other cross-contaminated food products.
Much effort has gone into food safety enhancement measures in the food manufacturing and retail / service industries in recent years. While the benefits of this effort have yet to be translated into an identifiable reduction in levels of foodborne illness, the combination of regulatory and industry actions has resulted in much greater awareness in the industry of the role it must play in reducing foodborne illness.
Consumers too have an important role to play in reducing the incidence of foodborne disease. While this role may be less well defined, minimisation of cross-contamination in the domestic kitchen is one area where education of the public should prove beneficial.
Raw foods, whether they be vegetable or animal products, can be contaminated with potential human pathogens including Campylobacter spp. In developed countries, one food with potential to cross-contaminate in the kitchen is raw poultry meat. There is little doubt that Campylobacter spp. will be spread around the environment when foods such as chicken are handled in either commercial or domestic kitchens (Journal of Applied Microbiology 90 2002 115S). While insufficient work has been published to confirm this situation as a major source of Campylobacter infection in humans, it is a situation over which the householder (as well as the commercial kitchen manager) can exercise some control. A recent study (International Journal of Food Microbiology 85 2003 213) investigates factors affecting the survival of Campylobacter, Salmonella and Escherichia coli during what is described as a typical washing-up process and the subsequent potential for transfer of bacteria to sites in the kitchen. Air-drying in organic matter, as would occur if dirty dishes were left for some time prior to washing-up, showed that Campylobacter survived very poorly in comparison with Salmonella and E. coli. This confirms earlier studies which showed that Campylobacter is very sensitive to desiccation whereas Salmonella and E. coli can survive for much longer periods.
The survival of these bacteria during a simulated washing-up was also investigated. Higher levels of bacteria than could be expected in practice were used but this was necessary to permit an accurate description of the inactivation that occurs. The main result to come from this part of the study was that a small elevation in washing-up water temperature could bring about a large increase in bacterial death rate.
The researchers recommend that washing-up water is used at the maximum possible temperature (using gloves to achieve this) and, if possible, a dishwashing machine which can reach much higher temperatures should be used.
A proportion of dishes that had been inoculated with E. coli, Salmonella or Campylobacter remained contaminated after a 'typical' washing-up process. Not all bacteria were physically removed or inactivated. The potential risk associated with the survival of Campylobacter during washing-up and cross contamination in the kitchen environment was considered to be small due to its sensitivity to detergent (0.1 per cent) and desiccation. Subsequent studies focused on Salmonella and E. coli.
When bacterial cultures were used to contaminate organic matter smeared onto dishes, E. coli transferred onto washing-up sponges and onto surfaces wiped with a contaminated sponge but Salmonella was not recovered from surfaces. Fresh sponges were used for these experiments so the possible buildup of pathogens in washing-up cloths that may occur in kitchens (Journal of Hygiene 93 1984 365) was not considered.
With higher initial levels of bacteria, both E. coli and Salmonella were recovered from kitchen surfaces and a higher proportion of swabs was contaminated. Bacteria transferred from dishes onto food more frequently when the dish had been towel dried rather than air dried but the overall frequency of transfer was low.
Frequent replacement or decontamination of tea towels and washing-up sponges is recommended.
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