Describe the micro-organisms responsible for food poisoning

conditions needed for bacteria to grow

Food: bacteria can thrive on most foods but prefer moist and high protein foods such as meat, poultry, rice, eggs and dairyproducts Moisture: Food poisoning bacteria needs moisture to stay alive They cannot multiply in dry food although they can remain dormant Warmth: Most food poisoning bacteria multiply between 5-63 degrees centigrade (the danger zone) At colder temperatures bacterial growth slows down and when food is frozen their growth is inhibited Time: Most food poisoning bacteria reproduce every 10-20 minutes

Bacillus cereus - Vomiting type

found in Cooked rice and causes nausea, vomiting, diarrhoea at a later stage. It produces spores Toxins from growth of bacteria in food.

Salmonella

found in Eggs, poultry, cooked meats, un pasteurised milk, insects and sewage It causes abdominal pain, diarrhoea, vomiting, headache and high fever. It is the most common bacteria in the UK and is destroyed by heat above 70°C.

Bacillus cereus- Diarrhoea type

found in cereals and cereal products, dust and soil. It causes diarrhoea, abdominal pains but rarely vomiting. It produces spores Toxins from growth of bacteria in food.

Listeria monocytogenes

found in cook chill foods and ready meals, untreated dairy foods and pate. It causes mild flu to serious complications and can cause miscarriage. Most at risk are pregnant women, newborn babies, the sick and elderly. Food needs to be stored below 5°C and the reheated thoroughly. However it can survive adverse conditions.

Campylobacter jejuni

found in raw meat, animal contamination. 96% of raw chickens contained this in recent tests. It causes diarrhoea, headache fever and abdominal pain. It can be destroyed by heat and is the most common cause of food poisoning in the UK.

Clostridium perfringens

found in raw meat, soil from root vegetables, dust and animal excreta and sewage. It causes abdominal pain, diarrhoea, nausea. It forms spores which produce a toxin. Spores develop in the danger zone and anaerobic conditions.

Escherichia coli 0157

found in raw meats, raw poultry, untreated milk, water and dairy products. It causes abdominal pain, nausea, diarrhoea, vomiting, kidney failure also causes gastroenteritis and can be fatal. It is sometimes called 'Traveller's Diarrhoea'.

Clostridium botulinum

found in soil, raw meat and fish and incorrect processing and packaging of meat. It causes difficulties breathing, swallowing and paralysis, double vision and headaches. Occurrences are very rare. The spores are very toxic and most cases are fatal. Essential to monitor food processing e.g. canning.

Staphylococcus aureus

found in the human body, droplet infection, raw milk, meat, meat products. It causes abdominal pain, severe vomiting and low temperature. It creates a toxin which causes the illness. High standards of personal hygiene are essential.

spores

Some types of bacteria such as clostridium botulinum can form spores which enable them to survive high temperatures Most bacteria are destroyed at temperatures of above 70 degrees centigrade but spores can survive up to 130 degrees centigrade. (The sterilisation process & canning can kill spores as food is heated to 132C)