Food Contamination There are three different types of contaminants: Physical Chemical Bacterial

Physical Contamination Is the presence of foreign bodies in food: Eg. Insects Glass Packaging material Objects off the food eg, chicken bones Parts of the machinery Food Handler eg. nails, hair, jewellery To reduce the risk of physical contamination: Only purchase stock from approved suppliers. Keep the food covered during storage and preparation. Keep potential physical contaminants away from food Chemical Contamination Can make food / drink poisonous or cause tainting which leads to an unpleasant taste or smell. Chemical contaminants can be: Cleaners- used to clean work surfaces. Copper pots- which can react with the food. Cans -when open can react with the food. Aerosols -which should not be used near food or food preparation surfaces.

Bacteria Bacteria are tiny living creatures often known as “germs”. They are so small that it is impossible to see them without a microscope. Bacteria are everywhere in: The soil Dust and water The air around us On our bodies Most bacteria are harmless and sometimes are even beneficial eg. in yoghurt and cheese making and they can aid digestion in our gut. Spores Some kinds of bacterial are capable of forming protective covering called spores. This protection enables bacteria to remain alive but inactive in situations that would normally kill them. Later if the conditions become suitable the spores change into the usual form of bacteria that then multiply rapidly. Spores can withstand high cooking temperatures and are able to survive situations where nutrients or moisture are not immediately available.

There are two types of bacteria that can cause a problem: Food spoilage Food Poisoning Food Spoilage Bacteria The main signs of food spoilage bacteria are changes in: Colour Texture Smell Taste Food displaying any of these signs are unfit to eat and must be discarded immediately. Food Poisoning Bacteria Cannot be detected by : Taste Smell Texture Colour Therefore dangerous foods can look perfectly normal. Types of food poisoning bacteria are: Salmonella – found in eggs, poultry Staphylococcus aureus – found in ears, nose, throat & wounds. E. Coli – found in raw meat. Clostridium perfringens – found in dust, dirt & soil. Bacteria cannot move on their own they have to be carried on to the food.

In order to multiply bacteria needs: Food ,Moisture, Time and Warmth Without all of these bacteria will be unable to multiply to a dangerous levels Food Bacteria grow on some foods more easily than on others There are two groups: High risk- foods which have a high protein content and contain moisture the main high risk foods are: Cooked meat and poultry Cooked meat products eg. gravy, soup and stock. Milk and egg products. Shellfish Cooked rice Low risk are low in protein and moisture They are foods containing sugar ,salt or acid, such as; Jams Pickles

Time Every bacterial cell multiplies by splitting itself into two. Every 10 to 20 minutes bacteria will double in number therefore within 4 or 5 hours one bacterium will have multiplied to many thousands. Moisture To grow bacteria needs moisture. Bacteria are less likely to survive in dried food, but once moisture is added start to grow.

Above 100oC are usually killed 73oC most bacteria will not survive Warmth Above 100oC are usually killed 73oC most bacteria will not survive Some bacteria will be protected by spores & they will come out & multiply. 64 – 72oC bacteria will survive but very few will multiply. This is the temperature that food should be kept at before serving. 5oC –63oC Bacteria that causes food poisoning will grow at these temperatures & grow most at around 37Oc 0-4oC bacteria multiply very slowly Below –18oC bacteria are dormant & will not multiply until they begin to defrost when they will grow again. Safe zone Danger Zone Safe Zone

Stomach ache Nausea Vomiting Food Poisoning Food poisoning is an illness people get from eating contaminated food The main symptoms are: Stomach ache Nausea Vomiting Diarrhoea Possible fever Some people are more at risk and these are: Babies/toddlers- do not have a fully developed immune system dehydrate quickly. People already ill- less able to fight symptoms. Elderly – immune system & defence mechanism are poor. Pregnant women – likely to pass symptoms onto the unborn baby, listeria can be fatal. The onset of symptoms is usually sudden and may start within 2hours of taking food but there may be an interval of several days. The illness typically lasts1or 2 days but sometimes can continue for a week or more.

Name of food poisoning bacteria Which food it is found in. Symptoms of food poisoning How it gets in food Salmonella Raw eggs, chicken, dairy foods, salad dressings etc Severe abdominal pain, diarrhoea, Nausea, vomiting Contamination from raw foods, dirty water, pests, people Staphylococcus aureus Cooked meat & meat products, poultry, dairy products Abdominal pain, diarrhoea, nausea, vomiting, Human nose, mouths, skin, cuts Untreated milk Bacillus cereus Cooked rice, milk & dairy foods meats, starchy products, vegetables Abdominal pain, watery diarrhoea, vomiting, Dust, soil E.coli Cooked foods, milk, seafood, salad Abdominal pain, diarrhoea, vomiting, fever Human sewage, dirty water, raw meat Clostridium perfringens Meat & meat products, poultry, gravy, stews Abdominal pain, diarrhoea Sewage, soil & dust, animals, insects, raw meat Listeria Coleslaw, pate unpasteurised soft cheese cook chill meals Fever diarrhoea, flu like illness, miscarriage Sewage, dirty water , soil Campylobacter Poultry, milk & milk products Persistent abdominal pain, diarrhoea often blood, headache Wild birds, animals. pests, water, sewage