Campylobacter is naturally occurring in the environment and lives in the gut of many animals, including chickens. Campylobacter is a common cause of bacterial food poisoning in humans. Food poisoning is not a new phenomenon, but the number of reported cases has increased steadily over the last few years. Food poisoning is almost always preventable when correct handling, storage and thorough cooking of food is observed.
The responsibility for food safety is shared between manufacturers, retailers, cooks, and consumers, and it is important that everyone involved in the production, distribution, and preparation of food understands the correct way of handling the variety of foods with which they deal.
People are becoming more aware and concerned about this type of illness and no longer assume that ‘tummy upsets’ must simply be endured. This view is right, because food poisoning is almost always preventable.
Campylobacter is a pathogen that has become the most common cause of bacterial food poisoning worldwide. Over 50% of cases in the UK can be attributed to fresh chicken which is why industry has invested a significant amount of resource and is committed to reduce the levels of campylobacter.
Food originates in fields and farms and it is constantly exposed to a wide range of micro-organisms present in the environment. Campylobacter is a naturally occurring bacterium that does not cause ill-effects in chickens. We have to accept that all fresh and natural foods may contain microbes that have the potential to be harmful if food is not handled and prepared correctly.
Everyone has a part to play in reducing the risks of bacterial food poisoning. Food safety must be observed ‘from farm to fork’; by producers, retailers, cooks, consumers, distributers.
It is important to note that appropriate storage and handling of food and thorough cooking will eliminate the risk of bacterial food poisoning.
This paper gives facts about campylobacter and information on the safe handling of foods, particularly products like poultry and meat.
Bacteria are simple organisms consisting of one cell. They are very tiny, usually spherical, oval, or rod-shaped and 500 typical cells would cover a pin head. Bacteria can be found almost everywhere in our environment.
They grow in soil, water, vegetation, and in humans and animals. Most bacteria are harmless and some are beneficial but some, termed pathogens, can cause illness.
Bacteria need water, warmth, and food to grow well. Growth can be very rapid; under ideal conditions one bacterium may multiply to 70,000 million bacteria in about twelve hours. Food poisoning bacteria will not grow in the freezer, or at temperatures above 60°C. The optimum temperature for the growth of food-poisoning bacteria is 20°C to 45°C. Outside these temperatures growth slows and at refrigeration temperatures (-2°C to +4°C), most dangerous bacteria do not grow at all.
Campylobacter is a genus (group) of bacteria which has a characteristic curved ‘S’ or spiral shape. This group of bacteria has been known to cause illness to animals for about 70 years, but its ability to cause illness in humans only began to be fully appreciated in the mid-1970s.
Since then, campylobacter has been the commonest cause of gastrointestinal infections in the UK. By 1988 there were over 28,000 reported cases, and by 2013 this had risen to over 70,000. Globally, campylobacter is one of the most frequent causes of diarrhoea.
In people, symptoms of campylobacter infection develop 1 to 4 days after ingesting the bacteria and infection may vary from mild diarrhoea to acute enteritis characterised by fever, headache, diarrhoea, and cramping abdominal pain. Deaths are very rare. The symptoms usually last for a few days, followed by recovery, but in about 25 percent of sufferers the bacteria is not immediately eliminated and relapses occur over several weeks. Campylobacter can have long-term effects for a minority of sufferers depending on the severity of infection; Irritable Bowel Syndrome (IBS), reactive arthritis or Guillain-Barré Syndrome which causes paralysis. Medical help should be sought for any lingering intestinal infections.
Campylobacter can occasionally cause illness in animals but it is very commonly found as part of the normal flora of healthy animals. Cattle, poultry, sheep, pigs, dogs, cats, and other domestic and wild animals all carry campylobacter. Pets in the home can pass campylobacter to their owners. Campylobacter is also very widely spread in the environment. Campylobacter in foods
Raw poultry, beef, offal and other meats as well as unpasteurised milk are the foods most likely to contain campylobacter. Unlike most other food poisoning organisms, campylobacter grows very poorly in food, and the numbers of this bacterium tend to decline as food is stored. Also, this bacterium prefers to grow in conditions where oxygen levels are reduced. However, campylobacter survives at refrigeration temperatures. Other foods are easily cross-contaminated by soiled surfaces, dirty equipment, dirty utensils, and dirty water.
Pets should not be allowed near food or food equipment and their feeding bowls should be washed and dried separately from other household washing-up.
Campylobacter has been termed the ‘barbecue bug’, but there is no special relationship between this bacterium and barbecues. Problems arise at barbecues because people are tempted to handle cooked food with hands contaminated by raw food or to eat the food before it is properly cooked. Barbecued food looks ready and smells delicious well before it is actually cooked through. If such half-cooked food is eaten, food poisoning by campylobacter, salmonella, and other bacteria may follow.
Cooking kills campylobacter
Campylobacter is killed by heat, so proper cooking completely eliminates this bacterium. Poultry and meat of all types, fish, eggs, and pastry products need to be heated through to 70°C or higher and held at this temperature for at least two minutes.
It is important to be sure that the centre of the food is adequately heated. Manufacturers’ cooking instructions, where given, must be carefully followed. Thermometers are used to check temperatures in professional catering operations, and they can be used in the home. Without a thermometer, poultry and meat can be tested by putting a skewer into the centre of the food to see if the juices run clear. If the juices are pink or red, more cooking is needed. Barbecued food should also be checked with a skewer.
How you can make sure the food you cook is safe
The poultry industry has a responsibility to produce the safest and highest quality products for consumers. We are involved in a wide-range of different initiatives to ensure that poultry products reach consumers’ kitchen in the safest possible condition.
However it is important for people to be aware that the food they cook at home for themselves and their family and friends can make them ill if correct hygiene practices are not followed. The food we eat is not sterile so everybody has a role to play to ensure food is safe to eat.
The FSA has created Kitchen Check so consumers can test their existing food safety behaviours in their own kitchen. This has a checklist allowing consumers to measure their behaviour against good practice and they also provide guidance on how to improve, with some top tips.
To ensure the food you cook is safe:
- Clear space and wash with hot, soapy water or disinfectant. Remove any pets from the kitchen
- Hands are one of the main ways germs are spread. You should wash them thoroughly with soap and warm water before starting any food preparation task and after touching raw meat products
- Make sure your fridge is set between 0°C and 5°C to prevent harmful germs from growing and multiplying
- Keep poultry and raw meat in covered containers on the bottom shelf to avoid raw juices contaminating other foods
- Wash your chopping board and knives in hot soapy water when you’ve finished with them and in between preparing raw and ready-to-eat food
- When possible, use dedicated chopping boards for each type of food
- Dirty, damp cloths are the perfect place for bacteria to breed. Food safety experts suggest you change or wash your tea towels, sponges, aprons and dish-cloths on a daily basis
- Use disinfectants and cleaning products that are designed for kitchen use
- Make sure poultry is properly cooked by cutting into the thickest part to check it is steaming hot, with no pink meat, and that the juices run clear.
Fresh produce should be refrigerated as soon as possible. Refrigerators should be set at between 0°C and 4°C; a thermometer will be needed to check the temperature. Campylobacter does not grow below 4°C.
Frozen poultry must be completely defrosted before cooking. Be sure there is no ice inside the bird, and that joints are not stiff.
Once the food has been cooked, it should be eaten immediately, or allowed to cool and placed in the refrigerator as soon as possible. Sandwiches, prepared salads, and cold dishes should also be refrigerated if not for immediate consumption.
Cooked foods must be stored at the top of the fridge and raw foods at the bottom on a tray or plate. Raw foods tend to drip. These drips could contain bacteria that may contaminate other foods. All foods should be covered or stored in sealed containers.
Today the poultry industry is more carefully regulated and managed than ever before. Government hygiene regulations are being revised and strengthened, and updated Codes of Practice backed by inspections are being followed by producers, processors and retailers.
Stringent measures are taken to control pathogens in poultry. A better understanding of food hygiene by all concerned with food preparation will prevent unnecessary illness.
What are producers doing?
Interventions are the actions taken at specific points in the production chain that have the best potential to either block or reduce the presence of campylobacter.
They are science-based and the result of the many projects undertaken since 2009.
Our key intervention points are:
- On farm biosecurity
- Catching practices
- Thinning practices
- Crates and modules
- Scalding practices
- Washing practices
- Heat treatments
- Cold treatments
- Novel packaging
This list represents those areas where research is suggesting the largest impact in the shortest time. Other intervention points, such as evisceration practices and kitchen hygiene awareness are still be examined.
On farm biosecurity
Good husbandry requires farmers to enter the houses a number of times every day to assess the health and welfare of birds, so consistent application of disinfectant foot dips, changing boots and clothing, and physical barriers to stop dirt entering from outside are important elements.
Red Tractor standards now have enhanced biosecurity requirement focused on campylobacter. This includes the human interaction with the flocks and also standards of cleanliness for all areas of the farm. Raising awareness of biosecurity, delivering appropriate training, and supporting consistent application are key areas of work for all chicken producing companies.
Research on model farms suggests that near perfect conditions and consistent application of working practices may give us a 10% reduction in the number of flocks infected by campylobacter. This has to be put in the context of farms being exposed to the environment and changing weather conditions, and the variability of working with livestock.
Clothing and equipment entering has to be clean and used in the correct manner. Focus has been on improving awareness and training of catchers, and this work is continuing.
Work is focusing on limiting the effects of thinning on the remaining birds. For example, reducing the potential for contamination in the catching process, and minimising stress in the rest of the flock that can exacerbate campylobacter colonisation.
Crates and modules
Traditional techniques that achieve visual cleanliness may leave campylobacter behind in a microbiological film, so work is on-going to enhance cleaning techniques, such as increased use of heat or improved application of disinfectant. Crates impregnated with silver (which has disinfectant properties) are also being trialled.
Practical methodologies for the handling and use of crates and modules are also being explored.
In the slaughterhouse scalding tanks are vats of hot water through which the bird carcase is passed before de-feathering.
This equipment often sees a build-up of foam on the surface of the water that can increase the risk of cross-contamination between birds. Work is being conducted to look at improving the efficiency of scalding, such as through the use of secondary or multi-stage equipment.
Research has shown that carcase washing equipment operating at a consistently high efficiency can reduce the amount of campylobacter on a carcase by up to 10%. Producers are working on systems designed to maintain high efficiency.
Campylobacter is sensitive to heat and cold and so interventions in these areas are being researched. Both heat and cold interventions must be balanced with the need to maintain the appearance of the bird that is acceptable to the consumer.
SonoSteam is an intervention that use a combination of ultrasound and steam to reduce the number of micro-organisms on the surface of the bird. More information can be found on their website.
Rapid surface chilling is the main focus as a chill treatment. This is where nitrogen or air at a very low temperature is sprayed onto the bird to lower the surface temperature and reduce campylobacter. There are a number of variations on this theme, such as the one developed by BOC. The initial trials have demonstrated a 1 to 1.5 log reduction on campylobacter (90% to 95) and the next step for this system is full scale production trials at 10,000+ birds per hour.
Many retailers are now introducing roast-in-the-bag whole chickens into their stores. By removing the need to handle the bird the intention is to reduce incidences of cross-contamination, and help consumers have good kitchen hygiene practices. The bag with the chicken inside is placed in the oven with the bag being cut open a short time before the end of cooking to allow the bird to brown.