Food safety

Fridge storage

• temp between 0^oC and 5^oC

  • bacteria multiplies slower- no warmth

• high risk foods stored in fridge

• cool food before refrigerating

• use date marks to rotate stock

• ensure spaces between items so air can circulate

• Stock rotation

Freezer storage

• temp at -18^oC or colder

  • bacteria becomes dormant- no moisture to multiply- enzymes may still be active

• freezers must be defrosted once a year to avoid a build up of ice

• ensure spaces between items so cold air can circulate

• Stock rotation

• Preferably allow food to defrost naturally

How to stop the spread of bacteria when preparing, cooking and serving food?

• Wash hands, keep fingernails short

• Don’t cough, sneeze over food, tie hair back, wear clean apron

• Clean work surfaces with antibacterial sprays Food handler

• Keep raw and cooked food separated and separate utensils

• Cook food to above 75C and cook for the correct time to kill pathogenic bacteria

Use by/ best before dates

• best before: sensory qualities (flavour, texture) safe to eat after e.g. bread, cereal (plant)

• use by: unsafe to eat after, moist, stored in fridge- could cause food poisoning e.g. chicken, fish (animal- high in protein)

How to use a temperature probe

1. Disinfect the probe before and after each use

2. Switch on

3. Insert probe into thickest part of the food

4. Wait for gauge to settle

5. Temperature should reach 75^oC

6. If not reached, cook for longer and repeat

How does yeast spoil food?

• Reproduce by bubbling- in air all around us

• Can grow with or without oxygen

• Prefers moist, acidic or high sugar foods e.g. orange, jam

• Best in warm conditions 25-29C, destroyed at temp over 55C

How does mould spoil food?

• Tiny fungus- in air all around us

• Likes high sugar/salt food- can grow on dry foods

• Mould spreads harmful substances deep into food

How does bacteria spoil food?

• Single celled microorganisms- harmless, pathogenic and food spoilage bacteria (causes good to smell and lose flavour and texture)

• Bacteria like warm, moist, neutral foods high in protein e.g. meat, milk, cooked rice

How to control bacteria?

• Take away warmth, moisture and time

• Remove (high risk foods) from danger zone 5C-63C and keep above (preferably 75C)

• Fridge 0 to 5C- slows down bacteria growth and slow multiplying

• Freezer -18 to -25C- bacteria dormant

Enzymic browning

• Enzymes mixing with oxygen in the air- spoiling food

• Prevent- use acid, blanching fruit and veg

Symptoms of food poisoning

• Vomiting

• Diarrhoea

Different types of bacteria

• Salmonella- undercooked meat

• Listeria- soft cheese, pate

• E Coli- undercooked meat

• Campylobacter- poultry, meat

Oxidation

• If you expose food to heat or air you lose water soluble vitamins

Microorganisms in food production

• Yeast- bread making- warmth, food, time and moisture, fermentation, fungus

• Mould- develop flavour in cheese, ripen the surface of some sausages

• Bacteria- harmless bacteria added to warmed milk- kept warm to allow bacteria to multiply

Use of bacteria in food production

• Cheese making- sours milk to create curds and whey, changes actors into lactic acid, which lowers the pH of the milk and starts the cheese making process

• Yoghurt making- bacteria added to warmed milk and allowed to multiply at 40C- lactose turns into lactic acid that denatures and coagulates the protein in the milk to thicken the yoghurt

Bacterial contamination sources

• Raw food- cross contamination

• Work surfaces- use antibacterial sprays

• Food handler- use tongs, don’t lick fingers

• Pests- insects, mice, empty bins

Who is more at risk from food poisoning?

• Babies, young children, elderly, pregnant women, reduced immune system

Causes of food poisoning?

• Undercooked food

• Incorrect fridge temp (0-5c)

• Cross contamination