Food safety Flashcards
What are the conditions needed by the bacteria to grow?
Warmth – Bacteria need warmth to grow. The temperature a food is stored, prepared and cooked at is crucial. If this is not followed correctly then the food will not be safe to eat. The optimum temperature range for bacterial growth is between 5-63℃. This is known as the
danger zone
as it is dangerous for some foods to be in this temperature range for prolonged periods of time.
Moisture – Bacteria need moisture in order to grow. This is why they grow on foods with high moisture content such as chicken. Foods that are dehydrated or freeze-dried can be stored for much longer as the moisture has been removed.
Food – Food provides energy and nutrients for bacteria to grow.
High risk foods
particularly protein foods such as chicken and dairy products are rich in nutrients and moisture and so promote bacterial growth.
Time – If provided with the optimum conditions for growth, bacteria can multiply to millions over a small period of time via
binary fission. This is when a bacterium divides in two every 20 minutes.
Suitable pH – Most bacteria reproduce best at a neutral pH level of 7. Acidic foods with a pH below 7, or alkaline foods with a pH above 7, may stop or slow down the rate of bacterial growth.
Food poisoning bacteria: Campylobacter
What food sources can it be found in?
Raw or undercooked meat, particularly raw poultry
Unpasteurised milk
Untreated water
Mushrooms and shellfish (only occasionally)
What are the symptoms?
Nausea
Diarrhoea (can be bloody)
Vomiting
Abdominal pain
High fever
How can you avoid/control it?
Cook meat, especially poultry, thoroughly
Prevent
cross-contamination
Don’t wash raw chicken
Wash pre-packed salads
Food poisoning bacteria: E. coli
What food sources can it be found in?
Raw or undercooked meat and poultry or related products (eg gravy)
Raw seafood products
Unpasteurised milk or products made from it (eg cheese)
Contaminated water
What are the symptoms?
Diarrhoea (can be bloody)
Vomiting
Abdominal pain
Fever
Kidney failure
How can you avoid/control it?
Prevent
cross-contamination
Thoroughly cook all meat and meat products
Wash hands after touching any animals/pets
Drink pasteurised milk and treated water
Food poisoning bacteria: Listeria
What food sources can it be found in?
Unpasteurised milk or products made from it
Soft cheeses (eg camembert, brie)
Ready-to-eat foods (eg pre-packed sandwiches, pâté, deli meats)
Unwashed vegetables contaminated with soil
What are the symptoms?
Flu-like symptoms (eg high temperature, aches and pains)
Nausea or vomiting
Diarrhoea
Can spread to nervous system and cause convulsions
In rare cases, can lead to septicemia (blood poisoning) or meningitis
can cause miscarriage
How can you avoid/control it?
Avoid
cross-contamination
Reheat ready-to-eat foods until steaming hot all the way through (core temperature of 70℃)
Use pasteurised milk and cheeses
Wash raw vegetables
Store raw meat correctly (on the bottom shelf of the fridge, under any cooked meat)
Food poisoning bacteria: Salmonella
What food sources can it be found in?
Raw or undercooked poultry or meat
Eggs
Unwashed fruit and vegetables
Unpasteurised milk
What are the symptoms?
Diarrhoea
Fever
Abdominal pain
Vomiting
How can you avoid/control it?
Thoroughly cook meat, poultry and eggs
Always wash hands after touching raw meat or egg shells and after using the toilet
Wash all fruit and vegetables
Avoid
cross-contamination
(keep any uncooked meat away from cooked food)
What rules should you follow for safety when purchasing food?
Check labels – Always check the
use by date
or
best before date
on food labels. This will reduce the risk of perishable foods causing food poisoning.
Check temperatures – check the temperature of chilled (below 4°C) and frozen cabinets (below -18°C) and ensure they are not overloaded.
Organise your shopping trip – minimise the time food spends in the danger zone. Always select your frozen or chilled foods towards the end of your shopping trip and pack these away from any hot food.
Take care when transporting your foods home – put chilled or frozen foods away immediately to prevent them from defrosting or spoiling. If you are more than 30 minutes away from the shop then bring a cool bag to keep them cool.
Do not buy any cans or packets that have been opened or damaged – food contamination or spoilage may have occurred.
Avoid cross-contamination – do not buy products from counters where raw and cooked foods are displayed together as this could increase the risk of cross-contamination. When packing foods in the trolley or in bags, ensure raw meats are kept separate from raw foods such as fruit and vegetables to prevent cross-contamination.
Observe personal hygiene of staff – do not purchase food if personal hygiene standards are not high from the staff serving or handling it. Report any unhygienic practices to the Environmental Health Department.
What is some food safety advice to storing food?
Stock rotation – when storing foods, stock rotation must be followed. This is when newer food is placed behind older food. It means that food which has been in the fridge, freezer or cupboard for the longest time is used before newer food, therefore reducing the risk of food poisoning and food waste.
Temperature control – the temperatures of chilled and frozen cabinets must be checked to ensure they are operating correctly. Refrigerators should operate between 1 to 4°C and freezers below -18°C. Below 5°C the cold temperature slows down bacterial growth or makes it dormant. Below -18°C is very cold, this will prevent any bacteria from multiplying.
Avoid cross-contamination in the fridge – raw meats must be stored on the bottom shelf of the fridge below any ready-to-eat foods to reduce the risk of meat juices dripping, thereby avoiding cross-contamination.
Cover and seal all food – keep all dry foods in sealed bags or containers and ensure the storage area is dry and cool. This will help keep the food fresh and avoid any spoilage.
Do not store any food or drinks near cleaning products or chemicals as they may contaminate the food
Cool leftovers as quickly as possible – before being placed into the fridge, leftovers should be cooled so they do not raise the temperature of other refrigerated foods and possibly cause food poisoning.
Read storage instructions – some foods such as jars and bottles need to be stored in the refrigerator once opened.
Take care when freezing foods – food being stored within a freezer should be carefully wrapped to avoid freezer burn. If a freezer is turned off and defrosted, all foods that have not been kept frozen should be disposed of.
Food safety advice when handling foods
Minimise time spent handling food – the longer a food is handled, the more it is exposed to an increase in temperature. The number of people handling the food should also be minimised to avoid food poisoning.
Hands should be thoroughly washed – all food handlers should follow the hand washing procedure before preparing food, after touching any raw meat, after using the bathroom or touching the nose, mouth, face or hair. Hair should be tied back before washing hands.
Dry hands – hands should be thoroughly dried as wet or damp hands spread bacteria more easily.
Keep nails short and clean – use liquid soap and a nail scrubber when washing hands as this is better at removing dirt from under nails.
Remove all jewellery when handling food – bacteria collect on the skin around rings or watches.
Cover any cuts or breaks in the skin with a blue waterproof plaster – the colour blue is used as it is more easily recognised if it falls into food as blue foods are rare.
Do not handle food if ill – food handlers must be excluded from preparing foods if they experience any vomiting or diarrhoea. A 48 hour exclusion rule must apply from when the symptoms of any illness stop naturally.
Food handlers should wear protective clothing – for example, an apron or a chef’s jacket. Clothing must also be clean and free of any animal hairs as these could transfer into the food being prepared.
Food safety advice when preparing and cooking foods
Preparing
Avoid cross contamination – chopping boards should be coloured coded so that raw meat is never cut on the same board as fruit and vegetables. Utensils should be washed after being in contact with raw meat to avoid cross-contamination.
Wash fruit and vegetables – all fruit and vegetables (especially root vegetables that may have excess soil) should be thoroughly washed to prevent the risk of spreading harmful bacteria such as E. coli.
Take care when defrosting foods – ideally, plan ahead and leave enough time to defrost food. Safe thawing should be done in small amounts in the fridge. Ensure meat and poultry are defrosted on the bottom shelf. If meat is thawed in the microwave, cook it immediately. Foods should be thoroughly defrosted before being cooked.
Keep work surfaces clean – it is important for food safety that all worktops are kept clean and free of bacteria. Use a clean cloth and anti-bacterial sprays. Ensure any surfaces are wiped clear of cleaning residue before preparing food.
Cooking
Temperature control when cooking food – all foods should be cooked for the correct amount of time and temperature. A food thermometer is the only safe way to check the core temperature of a food to ensure safety - especially when cooking meat, poultry and seafood. The core temperature of a food should reach 75°C instantaneously. The equivalent – for example 70°C for two minutes – is acceptable.
Follow label instructions – when cooking food it is important to follow the cooking instructions displayed on the label. This is especially important for foods cooked in the microwave as stirring and standing times are vital to ensure the core of the food has reached the required temperature.
Serving cooked foods – when a food is cooked it must be kept at 63°C and covered until it is ready to eat.
Reheating foods – When reheating a food, it should reach a core temperature of 70°C for two minutes. A food should not be reheated more than once.
