Food Hygiene. a workshop by Page 1

Transcription

1 Food Hygiene a workshop by Page 1

2 About Germs Germs are invisible except under a powerful microscope; hence the name micro-organisms or microbes. Microbes can be grouped according to their different structures; two common groups of microbes are viruses and bacteria. Not all bacteria are harmful indeed many are essential for life. The bacteria, viruses and other microbes that cause illness are commonly known as germs. Germs found in food can lead to food poisoning which can be dangerous and can kill though this is rare. They are very hard to detect since they do not usually affect the taste, appearance or smell of food. The most serious types of food poisoning are due to bacteria. The more bacteria present, the more likely you are to become ill. Bacteria multiply fast and to do so need moisture, food, warmth and time. The presence or absence of oxygen, salt, sugar and the acidity of the surroundings are also important factors. In the right conditions one bacterium can multiply to more than 4 million in just 8 hours. They multiply best between 5 and 60 o C but are killed at temperatures of 70 o C. At temperatures below 5 o C, most bacteria multiply very slowly, if at all. At very low temperatures some bacteria will die, but many survive and can start to multiply again if warm conditions return. That is why proper cooking and chilling of food can help reduce the risk of food poisoning. Page 2

3 Food Poisoning Germs can get into our food at any point in the food chain from the time when an animal or food is in the field to the moment food is put on to the table to eat. If they are allowed to survive and multiply, they can cause illness when that food is eaten. Sometimes these germs are spread to other foods, for example via hands, or kitchen utensils and cause illness when those foods are eaten. This is known as cross-contamination. The symptoms of food poisoning can last for days and include abdominal pains, diarrhea, vomiting, nausea and fever. The symptoms usually come on suddenly, but can occur several days after eating contaminated food. They will usually get better on their own. If symptoms persist, contact a doctor. Symptoms such as diarrhea and vomiting are not always due to food poisoning. Vulnerable Groups Food poisoning is more likely to affect people with lowered resistance to disease than healthy people who might show mild symptoms or none at all. Elderly or sick people, babies, young children and pregnant women are particularly vulnerable to food poisoning. Seek treatment if they have symptoms. Extra care should also be taken when preparing food for, and looking after, these vulnerable groups to minimize the risks of their coming into contact with food poisoning bacteria. Avoiding Food Poisoning Most food poisoning is preventable although it isn't possible to completely eliminate the risk. Food Storage Proper storage of food is an important part of reducing the risk of food poisoning. Some foods must be stored in the fridge and eaten within a short space of time; other foods, such as flour, pulses, canned foods and many others last much longer and can be stored at room temperature. But even dried foods have limits on their storage time. So watch out for storage instructions and make sure you always store foods: in the right place at the right temperature for the right time. Raw foods, such as meat and poultry, may contain microbes that can cause food poisoning. To prevent this, store them in the fridge. To avoid crosscontamination store these foods away from other foods, especially cooked foods and ready-to-eat foods (such as salads, fruit, cooked meats, cheeses, bread and sandwiches). Store them well covered, on the bottom shelf of the fridge so they can't drip onto other foods. Page 3

4 Eggs should be kept in the fridge, in their box. Keep prepared cold foods in the fridge until it's time to eat them. Dairy products belong in the fridge too. Many foods now need to go in the fridge once they've been opened check the labels to see which ones. Never put open cans in the fridge transfer contents into a storage container or covered bowl, and remember to use within two days. Store foods in separate covered containers. Cover dishes and other open containers with foil or film. Don't re-use foil or film to wrap other foods. Fridge/Freezer Maintenance Make sure your fridge/freezer stays clean and in good working condition: Use a thermometer to check fridge and freezer temperatures. The fridge should be at no more than +5 C and the freezer at -18 C or below. Avoid overloading. If a fridge is over-packed with food or iced up it's harder to keep the temperature down. Clean all internal and external surfaces often, especially fridge shelves and door storage compartments. Mop up any spills as soon as they happen. Defrost your fridge/freezer regularly. Store root vegetables away from other fruit and vegetables and in a dark place. Keep pests out. After opening packets of dried foods (eg flour, rice and breakfast cereals) reseal them tightly or transfer contents to storage jars. Select storage jars and containers with tightly fitting lids always wash and allow them to dry thoroughly after use. Check that safety seals are intact when first opening food packaging. Store cooking, eating and drinking utensils in cupboards and drawers and clean and tidy these storage spaces regularly. Storage time No food lasts forever however well it is stored. Most pre-packed foods carry either a 'use by' or 'best before' date. Check them carefully, and look out for advice on how long food can be kept for once packaging has been opened. 'Use by dates' are for highly perishable foods those that 'go off' quite quickly. No-one likes to waste food but it can be dangerous to eat foods past their 'use by' date. 'Best before' dates are for foods with a longer life. They indicate how long the food will be at its best quality. Even if a food is within these dates don't eat it if it looks tastes or smells off. Always throw away any fruit or veg that has started to rot and never eat food from rusty or damaged cans, or from leaking cartons. Page 4

5 Throw away perishable food that has been left out at room temperature for more than a couple of hours and all food scraps. Freezer Storage Times Check the label on pre-packed food to see if it is suitable for home freezing. If so, freeze as soon as possible after purchase. When freezing home-cooked foods, use clean freezer bags and label them with the date and description of the food. Again, check your freezer manual or cook book to see how long you can store the foods. Remember: Use up older items first first in, first out and if in doubt throw it out. Hygiene The microbes on our food that can cause food poisoning are usually controlled by heating (cooking) and/or chilling (refrigerating) our food, but given the chance they can easily spread around the kitchen via our hands, chopping boards, cloths, knives and other utensils. If they are allowed to cross-contaminate other foods especially cooked and ready-to-eat foods they can make us ill. Good kitchen hygiene and good personal hygiene are important to help control the spread of harmful germs. Kitchen Hygiene Clean kitchen surfaces after preparing foods. Try to 'clean as you go'. Remember that raw meat, poultry, fish and other raw foods can easily cross-contaminate other foods. After handling these foods always wash hands, utensils and surfaces thoroughly and before any contact with other food, especially cooked and ready-to-eat foods. After use, wash all crockery and utensils with industrial dishwashing machine. Change the water regularly then rinse in clean, hot water. Use the right amounts of salt and detergent and keep the filter and all surfaces clean. The highest temperature cycle will be most effective against germs. Keep all food cupboards clean, cool, tidy and dry. When you take cans from the cupboard, before opening wipe over the tops to remove any dust. And don't forget to clean the can opener. Give your kitchen a thorough 'spring clean' periodically. Page 5

6 Cleaning Materials Use the right materials for the job: Detergents such as washing up liquids are designed to dissolve grease, oil and dirt. Disinfectants, such as bleach, are designed to kill germs. These are powerful agents and should not be used indiscriminately. Anti-bacterial cleaners are types of disinfectant and can kill germs. They often come in spray form. Disinfectants and anti-bacterial cleaners won't work if you don't use them properly, so always follow the instructions. Always clean surfaces first with detergent to remove any grease and dirt, then apply disinfectant to kill any remaining germs. Use separate cloths or sponges for separate tasks; where practicable use disposable cloths. If using them more than once, wash in hot water and soap then place in a suitable disinfectant, rinse thoroughly and allow to dry. Do not soak overnight as disinfectant solutions weaken and may allow bacteria to grow. Use separate buckets, cloths etc for cleaning floors. Rubbish Kitchen rubbish bins are an obvious breeding ground for germs, so empty them regularly. Use a lidded bin and a bin liner. Tie up the rubbish bags before removing them to avoid food waste spilling onto the floor. Even with a liner, bins get dirty so clean them out with hot water and disinfectant at regular intervals. Pests and Pets Make sure that insects, birds and rodents are kept out of the kitchen and throw out any food they come into contact with. To control flies and wasps hang up an insecticidal strip (do not use aerosol sprays in the kitchen) and use traps for mice and rats. If the problem is serious, or if you have an infestation of cockroaches, ants or other pests, you might need to seek professional advice from your local environmental health department or a commercial pest control agency. Personal Hygiene When to Wash Hands Some germs can stay alive on our hands for up to three hours and in that time they can be spread to all the things we touch including food and other people. So wash your hands regularly throughout the day and especially at these times: Before: Preparing food Eating Caring for the sick; changing dressings, giving medicines Looking after babies or the elderly Starting work; especially if you are a food handler or health professional Page 6

7 Putting in contact lenses Between: After: Handling raw foods (meat, fish, poultry and eggs) and touching any other food or kitchen utensils Handling raw foods, particularly meat, fish and poultry Going to the toilet Touching rubbish/waste bins Coughing or sneezing, especially if you are sick Handling and stroking pets or farm animals Did You Know? The number of germs on fingertips doubles after using the toilet. Yet up to half of all men and a quarter of women fail to wash their hands after they've been to the toilet! How to Wash Hands We all think we know how to wash out hands but many of us don't do it properly. Page 7

8 Simply rinsing the tips of fingertips under cold water does NOT count. Here are some reminders: Always use warm water. It's better to wet hands before applying soap as this prevents irritation. Rub hands together vigorously for about 15 seconds, making sure both sides of the hands are washed thoroughly, around the thumbs, between each finger and around and under the nails. Then, rinse with clean water. Germs spread more easily if hands are wet so dry them thoroughly. Use a clean dry towel, paper towel or air dryer; it doesn't matter which. Did You Know? 1,000 times as many germs spread from damp hands than dry hands. Other Personal Hygiene Tips If you are ill, especially with any gastrointestinal problems, avoid handling foods for others. Don't sneeze or cough near foods. Cover all cuts, burns and sores and change dressings regularly pay extra attention to any open wounds on hands and arms. Avoid working in the kitchen in soiled clothing when cooking, use a clean apron but don't use it to wipe your hands on. Take off your watch, rings and bracelets as well as washing your hands and wrists before you start. Did You Know? If you wear a ring there could be as many germs under it as there are people in Europe. Millions of germs can also hide under watches and bracelets. Don't brush or comb your hair when you are in the kitchen or near food. Did you know? A 1mm hair follicle can harbor 50,000 germs. Do not cough, sneeze, spit or smoke near food and avoid touching your nose, teeth, ears and hair, or scratching when handling food. Keep nails short and not to use artificial nails or nail varnish. Always use waterproof dressings to cover any cuts or sores. Healthcare professionals and others who look after the sick also need to take extra care. Antiseptic or alcohol-based hand washing solutions provide extra safety. Page 8

9 Common bacterias that cause food poisoning Campylobacter Source: Campylobacter can be found in raw poultry and meat, unpasteurised milk, and untreated water. Pasteurised milk can be contaminated by birds pecking bottle tops on the doorstep. Pets with diarrhoea can also be a source of infection. Campylobacter is the most common identified cause of food poisoning. Characteristics: Illness may be caused by a small number of bacteria. Cross-contamination can lead to illness. Thorough cooking and pasteurization of milk will destroy Campylobacter. Symptoms: Symptoms include fever, headache and a feeling of being unwell, followed by severe abdominal pain and diarrhea which may be bloody. Symptoms normally take 2-5 days to appear but it can be as long as 10 days and return over a number of weeks. Salmonella Source: Salmonella has been found in raw meat, poultry and eggs, raw unwashed vegetables, unpasteurized milk and dairy products and many other types of food. It is found in the gut and faeces of animals and humans. Salmonella is the second most common cause of food poisoning. Characteristics: Salmonella survives when refrigerated although it is unable to multiply through cooking and pasteurization. Usually large numbers of the bacteria are needed to cause infection but outbreaks have been reported where infection has been caused by a low number of bacteria. Symptoms: It normally takes 12 to 48 hours for symptoms to develop. Symptoms may include fever, diarrhoea, vomiting and abdominal pain. Infection may be very severe, and in some cases may be fatal. It is particularly likely to cause severe illness in the very young and very old. Symptoms may last up to three weeks and there may be complications such as reactive arthritis. E Coli Source: E. coli is a widespread organism that is normally found in the guts of animals and humans. There are many different types, some of which are capable of causing illness. One uncommon type which can cause serious illness is Verocytotoxin producing E. coli O157 which has been found in raw and undercooked meats, unpasteurised milk and dairy products, raw vegetables and unpasteurized apple juice. Characteristics: Illness may be caused by a small number of bacteria, so cross-contamination can lead to illness. The bacteria can survive refrigeration and freezer storage, but thorough cooking of food and pasteurization of milk will kill them. Symptoms: Symptoms normally take about 2 days to develop but may start within a day, or take up to 5 days to come on. The main symptom is diarrhea. In some cases, particularly in children under the age of 6 and in the elderly, infection can lead to diarrhea which may be bloody and severe, kidney failure, and sometimes death. Page 9

10 Clostridium Perfingens Source: Clostridium perfringens is excreted by a wide range of animals. It can be found in soil, animal manure, and sewage, and also in raw meat and poultry. Characteristics: Clostridium perfringens produces spores which may not be killed during cooking. If foods are allowed to cool slowly, the spores germinate and produce bacteria which grow rapidly. These bacteria may not be killed if the food is not reheated until it is piping hot. It is particularly associated with gravies, cooked meat dishes, stews and pies and very large joints of meat and poultry. Symptoms: Symptoms are mainly abdominal pain, diarrhea and sometimes nausea starting usually 8-18 hours after eating the food. It may be fatal in the elderly and debilitated. Listeria Source: Listeria is widely present in the environment. It is found in soil, vegetation, raw milk, meat, poultry, cheeses (particularly soft mould-ripened varieties) and salad vegetables. It is also found in the guts of animals and humans. One type, Listeria monocytogenes, can cause illness in humans. Characteristics: Listeria monocytogenes, unlike most other food poisoning bacteria, can grow at low temperatures, even in the fridge. Thorough cooking of food and pasteurization of milk will destroy Listeria. Symptoms: It can take days or weeks for symptoms to develop. Symptoms can range from mild flu-like illness to meningitis and septicaemia; and in pregnant women, abortion, miscarriage or birth of an infected child. Other susceptible groups are those whose immune systems are compromised, the very young and the very old. People in these groups are advised to avoid certain foods, such as soft mould-ripened cheeses and pâtés, because of the risk of severe infection. Bacillus Cereus Source: Bacillus cereus is found in soil and dust. It is frequently found in rice dishes, occasionally pasta, meat or vegetable dishes, dairy products, soups, sauces and sweet pastry products where these have not been cooled quickly and effectively after cooking and during storage. Characteristics: Illness may be caused by a small number of bacteria, so cross-contamination can lead to illness. The bacteria can form spores; they are not easily destroyed by heat and will survive cooking of food. If food is cooled slowly or kept warm for some time before serving, the spores will germinate and produce bacteria. Bacteria can multiply rapidly at these temperatures and produce a very heat resistant toxin which will not be destroyed by subsequent reheating. Symptoms: Bacillus cereus can cause two distinct types of illness - a diarrhoeal form (diarrhoea and abdominal pain) with an incubation period of 8 to 16 hours and an emetic form (primarily vomiting, possibly with diarrhoea) with an incubation period of 1 to 5 hours. In both types the illness usually lasts less than 24 hours after onset. Page 10

11 Staphylococcus Source: Staphylococcus aureus may be found on the skin, in infected cuts and boils and in the nose. It may also be found in unpasteurized milk. It can be transferred to food from the hands or from droplets from the nose or mouth. Characteristics: Food poisoning from Staphylococcus aureus follows the consumption of heavily contaminated food, where bacteria have multiplied and produced a toxin which causes illness when the food is consumed. Staphylococcus aureus survives when refrigerated although it does not multiply. The bacteria is destroyed by pasteurisation of milk and cooking of food, but the toxin may survive these processes. The main foods associated with illness are cooked meats, poultry and foods which are handled during preparation without subsequent cooking. Symptoms: Onset of symptoms varies between 2 and 6 hours. Symptoms are severe vomiting, abdominal pains and diarrhoea. They generally last no longer than 2 days. Norwalk Viruses Source: Norwalk-like viruses are the commonest food borne viral infection and are usually spread from person to person. Characteristics: Norwalk-like viruses are transmitted from person to person (eg by projectile vomiting), environmental contamination and contaminated water. Food borne infection may be associated with sewage contamination of shellfish or fresh produce, or contamination by an infected food handler. Outbreaks occur most frequently in nursing homes and hospitals due to person to person spread. Symptoms: Norwalk-like viruses cause an acute gastro-enteritis and are the commonest cause of viral gastro-enteritis epidemics. Symptoms include vomiting and diarrhea. The symptoms take hours to develop, and last for about 2 days. Food Preparation The germs that cause food poisoning are at greater risk of multiplying and spreading when we are handling and preparing food. At these times we need to take extra care to control food temperatures and avoid cross-contamination. Handling Food Wash and dry hands thoroughly before handling food. When you can, use clean kitchen utensils not fingers for handling foods. Use rubber gloves. Keep raw and cooked food apart at all times. In particular keep raw meat, fish, poultry and other raw foods away from cooked foods and ready-to-eat foods (such as salads, bread and sandwiches). Wash and dry hands, utensils including chopping boards and knives and surfaces thoroughly after preparing raw meat, fish, poultry and other raw foods and before contact with other food. Ideally use separate chopping boards for raw and cooked foods. Use disinfectants on utensils, chopping boards and food handling surfaces. Page 11

12 Never put cooked food onto a plate which has previously held these raw foods until it has been thoroughly washed. Do not use the same utensil to stir or serve a cooked meal that was used to prepare the raw ingredients. Root vegetables such as potatoes, leeks and carrots often have traces of soil on them which can contain harmful bacteria, so wash them thoroughly before use. Don't forget to wash other fruit and veg too, especially if they are going to be eaten raw. Avoid preparing food for yourself or others if you are ill, especially with vomiting and/or diarrhea. Defrosting When cooking pre-packaged frozen foods always follow instructions on defrosting and/or cooking from frozen. If cooking from frozen allow sufficient time for food to be thoroughly cooked and check it before serving. When defrosting foods make sure they are fully defrosted before cooking. Allow food enough time to thaw. Never re-freeze food once it has started to thaw. Thaw food by placing it on the bottom shelf of the fridge in a container to catch any juices. These juices can be contaminated so wash dishes and hands thoroughly after use. Only thaw food in a microwave oven if it is to be cooked immediately. To thaw very large turkeys etc more quickly, let them defrost outside the fridge. Put them in a cool place and make sure they are completely thawed before cooking. Cooking and Heating Follow recipes and label instructions on cooking times and temperatures. Remember to preheat the oven properly. Cook all foods until they are piping hot. Double check that sausages, burgers, pork and poultry are cooked right through; they should not be 'rare' or pink in the middle and when pierced with a knife any juices that run out of the meat should be clear, not bloody. Elderly or sick people, babies, young children and pregnant women should only eat eggs cooked until both yolk and white are solid and should not eat raw or partially cooked fish and shellfish. Lamb and beef (except when minced or rolled) can be eaten rare - but make sure the outer surface is thoroughly cooked to kill any germs on the surface of the meat. Don't cook foods too far in advance. Once cooked, keep foods covered and piping hot (above 63 o C) until it's time to eat them. Keep prepared cold foods in the fridge until it's time to eat. Page 12

13 When using a microwave, stir foods and drinks and allow them to stand for a couple of minutes to avoid hot or cold spots. Check food is piping hot throughout before serving. Reheat foods until they are piping hot right through. Don't reheat foods more than once. Cooling Do not put hot food directly into the fridge or freezer, let it cool sufficiently first; but remember that cooling should be completed within one or two hours after cooking. To speed cooling divide foods into smaller portions, place in a wide dish and stand this in a shallow tray of cold water. Page 13