By Dr Sally Best
Poultry (chickens, ducks, quail, guinea fowl, geese and other domestic birds) benefit human health because meat and eggs from birds provide healthy and nutritious food. This article outlines the main benefits and risks to humans that are associated with poultry keeping and consumption, and describes how to keep the risks as low as possible so that the benefits can be enjoyed to the full.
Chicken meat and eggs are widely available across the world. Chicken meat is usually the cheapest of all domestic livestock meats and eating it is largely without cultural taboos. The health benefits of eating both chicken meat and eggs can be enjoyed by most people across the developing world. For this reason we will focus on chickens as we look at health benefits, although a lot of the information is relevant to other poultry.
Eggs provide nutrients that are important for keeping people of all ages healthy and strong. Eggs also provide important vitamins and minerals. In fact poultry products are rich in almost all essential nutrients except vitamin C. Because of the nutrients they contain, eggs are important for your brain and memory, they help keep your eyesight strong, help your body produce energy, protect you from disease, help unborn babies develop properly and keep muscles, bones and teeth strong.
Folic acid for expectant mothers
When women do not consume enough folic acid from the very early stages of pregnancy, they are at increased risk of miscarriage, stillbirth, or having children with severe brain and spinal cord defects. Eggs are a good source of folic acid and so eating them during pregnancy will reduce these risks.
Protein for strength and healthy growth
Protein is essential for building and repairing muscles, organs, skin, and other body tissues and is particularly important to help young children grow. Chicken meat and eggs are an excellent source of good quality protein.
Good fats not bad fats
Chicken meat is a healthy meat because it has a low overall fat content. Unlike beef and lamb, it does not contain the type of fat which contributes to heart disease, and it also contains a lower proportion of other unhealthy fats compared with most red meats. Approximately half of the fats in chicken are helpful fats.
Omega-3 fatty acids
Recently, experts have begun to realise the importance of omega-3 fatty acids for human health. They have a wide range of benefits including protection from diseases such as cancer, heart disease and arthritis. They are also particularly important during pregnancy and early infant development. If chickens are fed flax seed, rapeseed or rapeseed oil, or fish oil, the amount of omega-3 fatty acids in their eggs will be increased. This is known as enrichment. Enriched eggs can be a very good source of omega-3 fatty acids, especially in areas where fish and seafood (another good source of omega-3) are not available or are too expensive.
Eggs are healthy
In the past there have been warnings that eating too many eggs could increase the risk of heart disease because it was thought that cholesterol in eggs was bad for you. However, eating one or two cooked eggs a day is good for most people as they have many health benefits.
Human health can be put at risk by contact with live birds or by eating poultry products. However, simple hygiene measures can dramatically reduce these risks.
Contact with live birds increases risk of Avian flu
Humans can sometimes catch Avian flu from contact with diseased birds, although this is relatively rare. According to the World Health Organization only 650 people had caught Avian flu between 2003 and the end of 2013 but it is a dangerous disease because more than half of these people died.
It is important to protect your poultry flocks from Avian flu and to follow advice on what to do if you think your flock is infected. Birds that are infected, or might be infected, should never be sold, given as gifts or prepared as food. It is very important to take great care when handling and disposing of diseased birds. For more information see the article on Avian flu on page 14.
Eating contaminated poultry products increases risk of food poisoning
Poultry meat and eggs may be contaminated by harmful bacteria that can cause food poisoning in humans. Dangerous bacteria often live in the birds’ guts. These bacteria may contaminate the meat during slaughter and processing. Humans may also introduce harmful bacteria when handling poultry products.
Children, people who are malnourished, people in war zones, or those living through natural disasters are most vulnerable to food poisoning because their bodies are weaker and under stress. Although food poisoning can be mild, it can also be very severe and even fatal. The main symptom is diarrhoea often accompanied by vomiting.
The risk of food poisoning from meat is low when backyard birds are slaughtered at home and are immediately prepared, cooked and eaten. Furthermore, because a single bird can often be consumed by a family in a single sitting, the risks associated with storing meat are avoided.
The risk increases when poultry production, slaughtering, processing and consumption take place at different times and in different places. In particular a lack of refrigeration during marketing of meat produced on a large commercial scale is a big risk factor.
Reducing the risks
Reducing the risks during slaughter and processing
This section describes hygiene measures for small-scale slaughtering facilities to prevent contamination. The same hygiene principles can also be applied when birds are slaughtered at home.
Reducing the risks during marketing and storage
- Slaughtering facilities should be divided into three separate areas: (i) an area for live birds, (ii) an area for killing and defeathering, and (iii) an area for processing (gutting, rinsing, chopping and/or packaging).
- Birds should be as clean as possible when they arrive for slaughter. For example, during transport poultry crates should not be stacked on top of each other unless they have solid bases – this will help prevent faeces from one bird soiling another.
- Workers should wash their hands and their tools often throughout the whole process.
- Workers should avoid splashing bird blood on themselves and their clothes.
- Birds should be placed head-down in slaughter cones, above a trough to collect the blood, to prevent the spread of disease by blood spray, flapping and loose feathers.
- Water used for scalding (to loosen the feathers before plucking) should be frequently replaced.
- Avoid spilling the contents of the intestines on the meat during gutting.
- The carcasses should be rinsed with water that is clean enough to drink, kept as cool as possible. They should also be hung to prevent contamination from work surfaces.
- Flaming the surface of the carcass is also a good way to reduce the number of bacteria that may remain, but quick chilling at 4-10°C is the best way of preventing bacterial growth.
- Wrapping in a clean plastic bag prevents further contamination before sale.
- All waste (stripped carcasses, blood, offal, feathers etc.) should be burned or buried. (Note: feathers for trade, such as down for making bedspreads and clothing, need to be pasteurized to make them safe. Pasteurizing is heating to a temperature that kills most bacteria without changing the product. It is only partial sterilisation and requires specialist knowledge.)
- If frozen, poultry meat must remain frozen throughout the marketing chain. Defrosting meat on market stalls is a big risk because bacteria survive in frozen food and then start to multiply again once the food is defrosted. Therefore, defrosted meat should be cooked immediately and eaten.
- Refrigeration helps eggs last longer.
Reducing the risks during food preparation
- All poultry meat and eggs should be well cooked to kill any bacteria and prevent food poisoning. However, even thorough cooking will not get rid of some of the toxins that the bacteria produce, so it is still important to slaughter birds properly and store food well.
- All other poultry products, such as blood pudding or blood soup, should also be well cooked.
- You can check if your egg is still good by placing it in a bowl of water. If it floats to the top it is rotten. This works for fresh eggs and hard-boiled ones.
- If eggs smell bad, they are bad.
- If other foods, such as vegetables, come into contact with raw chicken they become unsafe unless also thoroughly cooked.
- Do not keep leftover meat and eggs in warm places. Eat it all at the first sitting, or refrigerate it.
Enjoy the benefits
The benefits of consuming poultry products outweigh the relatively small risks when you take good advice and put it into practice. Most importantly, if you live in an area at risk of Avian flu then protect your flock, and handle and dispose of flu-infected birds with care. If refrigeration is not available, consume your poultry as soon as possible after slaughter and cook all poultry products thoroughly. Remember, chicken and eggs are very good for you, so take these precautions and enjoy safe and nutritious food!
Dr Sally Best is a medical writer with previous research experience in zoonotic diseases and is a member of the Footsteps editorial committee.