Tokyo Food Safety Information Center » Preventing food poisoning » Campylobacter food poisoning: Be aware and prevent it » More detailed explanation about Campylobacter (Q&A)

More detailed explanation about Campylobacter (Q&A)

This Q&A was compiled by the Tokyo Metropolitan Government Food Safety Information Evaluation Committee when it carried out investigations aimed at reducing Campylobacter food poisoning in light of the increase in this kind of food poisoning over the past few years.

Q&A Contents

Basic knowledge

1.	Campylobacter and Campylobacter food poisoning
2.	Food and Campylobacter
3.	Other

Application and countermeasures

1.	Eating chicken
2.	Cooking chicken

Basic knowledge 1. Campylobacter and Campylobacter Food Poisoning

Q1.	What kind of bacterium is Campylobacter? Where is it present?
A1.	Campylobacter (jejuni/coli) is a pathogenic bacterium that causes food poisoning. As it is microaerophilic, it prefers a low-oxygen environment, and cannot multiply in the normal atmosphere where there is plenty of oxygen or, conversely, in an environment where there is no oxygen at all. Moreover, the temperature range in which it can grow (multiply) is 30˚C to 46˚C. Its main habitat is the gastrointestinal tract of animals such as cows, pigs, sheep, chickens, dogs, cats, pigeons and other, and it has been detected in the feces of these animals.
Q2.	Why are you raising awareness about Campylobacter?
A2.	The reason for this special focus on Campylobacter is that Campylobacter food poisoning, which should be relatively easy to prevent with adequate cooking and thorough prevention of secondary contamination, has increased over the past few years. In particular, there have been many outbreaks of Campylobacter food poisoning associated with restaurants and school cooking classes. For that reason, we want people who cook and people who eat to understand this kind of food poisoning correctly, grasp the key points for preventing food poisoning, and enjoy delicious meals.
Q3.	What kind of symptoms does Campylobacter food poisoning produce?
A3.	The main symptoms are diarrhea, abdominal pain and fever. In addition, symptoms such as fatigue, headaches, dizziness, and muscle pain can occur, but the prognosis is relatively good. The initial symptoms are sometimes mistaken for a cold.
Q4.	How long does it take for symptoms to appear after the bacteria enter the body?
A4.	The period between ingesting the bacteria and the appearance of symptoms (the incubation period) is two – seven days (on average two – three days), which is a long period compared with other bacteria that cause food poisoning and is one of the characteristics of Campylobacter food poisoning.
Q5.	How should the symptoms be treated once they have appeared?
A5.	The initial symptoms of Campylobacter food poisoning (diarrhea, abdominal pain, fever, etc.) are not specific to this kind of food poisoning. Therefore, you cannot determine what illness is causing the symptoms by yourself. Depending on the type of food poisoning, symptoms can be exacerbated by anti-diarrhea medications based on self-diagnosis, so, if the diarrhea and abdominal pain are severe, you should be sure to undergo an examination at a medical institution to investigate the cause and receive the appropriate treatment.
Q6.	What kind of people are particularly susceptible to Campylobacter food poisoning?
A6.	In general, age groups with relatively weak resistance such as small children and the elderly and people with a lowered immune function such as occurs during and after illness are susceptible to food poisoning and infectious diseases. In the case of Campylobacter food poisoning, it has been reported that many patients are children aged 0-4 and young people aged 15-25. (It is thought that the cause of the large number of infections among young people could be the large number of dining opportunities such as food on overseas trips, barbeques and so on rather than the presence or absence of resistance.) In addition, it has also been reported in Japan that there are many cases of in-patient treatment among children aged nine and younger.
Q7.	Could you please explain the mechanism by which Campylobacter causes food poisoning?
A7.	There are various types of food poisoning, including those caused by toxins produced by bacteria in food, those caused by toxins produced by bacteria after they enter the gastrointestinal tract, and those in which the bacteria themselves cause inflammation in the gastrointestinal tract. It is thought that Campylobacter multiplies after entering the stomach and develops into food poisoning, but the detailed mechanism is not yet understood clearly.
Q8.	I have read in the newspaper that chicken is associated with the occurrence of Campylobacter food poisoning. Is that true?
A8.	Results from studies of what people with food poisoning had eaten show that there are many cases in which chicken is involved in the occurrence of Campylobacter food poisoning, but that is not to say eating chicken is dangerous. It is thought that specific factors lead to the occurrence of food poisoning. These include eating raw chicken and eating chicken without cooking or heating it properly as well as ingesting Campylobacter when the bacteria is present on other food via hands that have been handling chicken or utensils used for preparation.
Q9.	Do other meats such as beef or pork cause Campylobacter food poisoning?
A9.	As stated in Q1, Campylobacter also lives in the gastrointestinal tracts of cows and pigs. Cases of Campylobacter food poisoning caused by cow’s liver sashimi have been reported, and meat other than chicken is not completely unproblematic. Therefore, small children, the elderly, and people with low resistance should eat meat other than chicken after cooking as well.
Q10.	Eating what quantity causes food poisoning?
A10.	One of the characteristics of Campylobacter is that a small number of the bacterium cause food poisoning. According to overseas reports, there have been cases caused by a few hundred bacteria. This is a rather small number of bacteria compared with most of the bacteria that cause food poisoning, which apparently do not cause symptoms unless 100,000 – 1,000,000 bacteria are ingested. Considering this, when Campylobacter is present in food, just a taste could cause the onset of symptoms.

Basic knowledge 2 Food and Campylobacter

Q11.

How is hygiene for chicken maintained?

A11.

Plants that process chickens into chicken meat (poultry processing plants) must observe standards (facility and water used, etc.) based on the Poultry Processing Act*. In addition, individual examination of chickens is mandatory, and measures such as the exclusion of diseased birds are taken.

*Poultry Processing Act
Poultry Slaughtering Business Control and Poultry Meat Inspection Act

Q12.

Why is Campylobacter present in chicken?

A12.

Campylobacter lives at a relatively high rate in the gastrointestinal tract of chickens, but, as it is not a pathogenic bacterium for chickens, birds that are carrying Campylobacter are not excluded through poultry inspections. Poultry processing plants usually process many chickens in a short period of time, so that the Campylobacter in the gastrointestinal tract of the chickens sometimes gets onto the meat.
A variety of bacteria live in the gastrointestinal tracts of chickens, and the reality is that it is difficult to process large volumes of chicken meat aseptically using conventional processing methods.

Q13.

Is Campylobacter present on the chicken sold in supermarkets, etc.?

A13.

Campylobacter is not always present. However, when the Tokyo Metropolitan Government has conducted surveys, Campylobacter was present on 40 – 60% of the chicken distributed for sale. In general, various kinds of microorganisms, including bacteria that cause food poisoning, have been detected in meat, and many challenges remain for the production of completely sterile chicken meat, both in terms of technology and cost.
Nevertheless, even when Campylobacter is present on food, it is possible to adequately prevent food poisoning if you cook it in accordance with the preventative measures explained in this Q&A.

Q14.

Is there a problem with eggs?

A14.

So far there have been no reports of Campylobacter food poisoning in which the consumption of eggs is the suspected cause, so it is thought that there is no problem with eggs. For example, even if the bacteria are present on the shell of an egg, Campylobacter, which is easily affected by dryness, will die quickly as the surface of the shell is dry.

Q15.

Is there a problem with chicken extract and bouillon?

A15.

Campylobacter is a bacterium that is susceptible to damage due to changes in the environment. For example, it is easily affected by heat and dryness and generally cannot even survive in the air. Therefore, Campylobacter is not present in chicken extract and bouillon produced through processes such as heating and concentration.

Q16.

Is there a problem with eating chicken raw if it is fresh enough?

A16.

Because even a small amount of Campylobacter causes food poisoning, chicken has the potential to cause food poisoning irrespective how fresh it is, assuming that Campylobacter is present on the meat.
However, you should cook and eat meat as soon as possible because other pathogenic bacteria may increase as it becomes less fresh.

Q17.

Does Campylobacter die if it is frozen?

A17.

Campylobacter has also been detected in chicken that has been frozen, so it can be said that it does not die completely even if frozen.

Q18.

Does the taste of the food change if Campylobacter is present?

A18.

Unlike when food spoils, the presence of Campylobacter does not affect the taste or the smell, and there are no particular visible changes.
This is the case with many kinds of food poisoning, not just Campylobacter.

Q19.

In order to prevent Campylobacter food poisoning, what kind of things do we need to careful about when cooking and eating chicken?

A19.

The three factors below are considered to be the main causes of Campylobacter food poisoning where chicken is suspected to be involved.

1.	Insufficient cooking/heating of chicken
2.	Ingesting bacteria present on chicken that got onto other foods via cooking utensils and hands
3.	Eating raw or nearly raw chicken

Please read the Application and countermeasures Q&A so that food poisoning due to these causes does not occur (is not caused).

Basic knowledge 3 Other

Q20.	Can we prevent food poisoning caused by other bacteria and viruses if we are careful about Campylobacter food poisoning?
A20.	The bacteria and viruses that cause food poisoning have various characteristics, and include ones that are resistant to and ones that are easily affected by heat and dryness and so on. Preventive measures that match the characteristics of each bacterium and virus are required. However, there are also many common points such as cooking and hygienic handling of ingredients. The Tokyo Metropolitan Government calls for thorough handwashing and temperature management based on the slogans, “Do not spread bacteria,” “Do not allow bacteria to multiply,” “Kill bacteria” as preventive measures against food poisoning in restaurants and homes. In addition, the Ministry of Health, Labour and Welfare recommends the practice of “HACCP in home” based on the HACCP approach as a countermeasure in the home. Although not 100% safe, the majority of food poisoning can be prevented by observing the basics of food poisoning preventive measures. [Reference] HACCP: Hazard Analysis and Critical Control Point A food hygiene management technique, which has been adopted around the world, that attempts to assure the safety of all final products by managing processes that are critical to ensuring safety through conditions based on scientific grounds
Q21.	Is there any connection between Campylobacter food poisoning and avian influenza?
A21.	There is no connection. Campylobacter is a bacterium that causes food poisoning in humans. Avian influenza is a virus that is highly pathogenic in birds. If you would like to know more about avian influenza, please see the Infectious Disease Surveillance Center website.

Application and countermeasures 1 Eating chicken

Q22.

Is it alright if you cook it and eat it soon after? Does the risk of food poisoning increase with time?

A22.

Campylobacter is a bacterium that does not tend to multiply in food, so the amount of time after cooking is not related to an increase in the risk of food poisoning. However, Campylobacter will be eliminated in food that has been thoroughly cooked.
However, the risk of food poisoning due to other bacteria does increase with time. You should also eat food soon after cooking so that your meal tastes good.

Q23.

What precautions are needed when everyone gathers round to eat together such as with hotpots and barbequed meat?

A23.

The following are thought to be the main causes in cases when Campylobacter food poisoning occurs with dishes such as hotpot and barbequed meat.

1.	Chicken on which Campylobacter is present is eaten without being adequately cooked/heated.
2.	Campylobacter, which is present on chicken, gets onto vegetables and chopsticks and is ingested.

The following precautions are required for dishes such as hotpot and barbequed meat.

1.	Cook/heat meat and vegetables adequately before eating (please see Q26 and 27 for cooking/heating method for chicken).
2.	Use special chopsticks or tongs for handling raw meat, and do not eat with chopsticks and other utensils that have been in contact with raw meat.
3.	Prepare meat and vegetables on separate plates.

Q24.

Is it best not to eat toriwasa and chicken sashimi at home?

A24.

If you could use chicken in which the bacteria that cause food poisoning are not present, then it would not be a problem, but you cannot tell whether these bacteria are present or not by looking.
In results of surveys conducted by the Tokyo Metropolitan Government, Campylobacter has been detected in 40 – 60% of the chicken distributed for sale. Therefore, it is estimated that Campylobacter is present in a fairly high proportion of chicken. Moreover, in cooking experiments, Campylobacter could not be completely killed by heating that is equivalent to blanching.
Based on this, it is thought that eating toriwasa, which uses chicken that is mostly uncooked, and chicken sashimi, which is raw chicken, at home involves a high risk of food poisoning, so it should be avoided. In particular, small children, the elderly and other people with low resistance are considered to be susceptible to infection, so care should be taken that they do not eat (are not fed) toriwasa or chicken sashimi.
The Japanese government has also stated that eating raw or nearly raw chicken cannot be recommended from the perspective of preventing food poisoning (March 9, 2004, Food Safety Commission of Japan, Ministry of Health, Labour and Welfare, Ministry of Agriculture, Forestry and Fisheries, and Ministry of the Environment).

Q25.

Is the toriwasa and chicken sashimi served at restaurants safe?

A25.

It is technically possible to ensure that Campylobacter is not present in chicken meat by paying meticulous attention to chicken processing. Except for when this kind of chicken meat is used, eating chicken sashimi or toriwasa that uses chicken meat which is mostly uncooked carries the risk of food poisoning.
In particular, small children, the elderly, and other people with low resistance are considered to have a greater possibility of contracting food poisoning, so it is recommended that they do not eat chicken dishes that are raw or nearly raw.

Application and countermeasures 2 Cooking chicken

Q26.

Could you explain the heating guidelines for making dishes in which Campylobacter is not present?

A26.

Results have been obtained from cooking experiments showing that Campylobacter is virtually eliminated if meat is heated until the color of the center changes from pink (the color of raw meat) to white when grilling, boiling, or frying, including grilled fish, meat dumplings, and deep fried chicken. You should use the change in the color of the meat as a guideline for when it is ready to eat.
When meat is cooked over a powerful flame such as with a barbeque, it is sometimes still raw in the middle even though the surface looks ready to eat. You should cook the meat well and eat it after checking that it has changed color through to the center.
Moreover, when we tested the effect of cooking chicken by submerging it in boiling water, which is referred to as “parboiling,” Campylobacter was not destroyed. It is considered difficult to make food that does not contain Campylobacter by cooking it this much.

Q27.

Up to what temperature should it be heated to be safe?

A27.

Campylobacter is virtually destroyed by heating it at 65˚C for several minutes, but it likely to be difficult to measure the temperature of the meat and the duration of heating while cooking, so you should use the change in the color of the center of the meat (change to white from the color of raw meat) as a guideline to how well it is cooked.

Q28.

What kind of things should we be careful about when handling raw chicken ?

A28.

If we investigate the causes of Campylobacter food poisoning that has occurred in the past, apart from eating raw or nearly raw chicken, there are many cases thought to have been caused by Campylobacter that was present in chicken getting onto other foods via cooking utensils or hands (secondary contamination) and being ingested. When handling raw chicken, you should pay attention to the following.

1.	Be sure to wash your hands that have been handling raw chicken before touching other items (please see Q34 for handwashing procedure).
2.	As much as possible, you should use a special chopping board for preparing meat and do not use it for vegetables and other foods as well. If you must use it for vegetables and other foods, be sure to wash cooking utensils (knives that have cut chicken, chopping boards, bowels, etc.) before handling the next food (please see Q31 through Q33 for washing procedures for utensils).

Q29.

Does it spread to other foods in the refrigerator?

A29.

Campylobacter does not get onto other foods in the refrigerator unless they come into contact with uncovered chicken or meat juices leak from chicken. You should put chicken into a container with a lid for storage.

Q30.

Are there any precautions when storing chicken?

A30.

In order to prevent food poisoning by pathogenic bacteria other than Campylobacter, you should store chicken by refrigerating or freezing it promptly after purchase.

Q31.

What should I do with cooking utensils after handling chicken?

A31.

You should refrain from using cooking utensils such as chopping boards and bowels that have been in contact with raw chicken for other cooking as they are. In particular, care is required when handling ingredients that will not be cooked such as salads and dressed foods.
Pouring plenty of boiling water over utensils after washing them is effective for removing Campylobacter from used cooking utensils.

Q32.

Does washing cooking utensils with detergent remove bacteria?

A32.

In testing, washing cooking utensils with detergent succeeds in reducing the bacteria to some extent. It is considered that this by itself is quite effective in the prevention of food poisoning, but pouring plenty of boiling water over utensils after washing is even more effective.
It is recommended that during cooking you also take the trouble to pour boiling water on utensils after washing them. In particular, you should take care to eliminate bacteria in homes where there are small children.

Q33.

Are there any methods of disinfecting cooking utensils that can be easily implemented?

A33.

When we tested various methods of disinfection, adequately effective disinfection was obtained by, for example, soaking cloths in boiling water or chlorine bleach for at least one minute and pouring plenty of boiling water over chopping boards as in Q32.
Moreover, Campylobacter is easily affected by dryness so exposing utensils to the sun after washing to dry them is also effective.

Q34.

How should I wash my hands?

A34.

For handwashing when cooking, a pump-type liquid soap is preferred as it can be used more hygienically than hard soap.
Results have been obtained in handwashing tests showing that bacteria on hands can be reduced to less than 1/1000 (including bacteria other than Campylobacter) by carefully washing twice with liquid soap.
It is difficult to remove the bacteria adhering to the hands together with meat by only washing with water or once with soap. After touching meat, you should wash your hands at least twice with liquid soap before doing other cooking.

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