4. Food Safety

• Bacteria - small microorganisms.

  They can be harmful and cause food poisoning, but some harmless ones are useful in making cheese and yoghurt.
• Bacteria growth conditions:

  • Temperature: Bacteria multiply between 5 degrees and 63 degrees Celsius, but work best at 37 degrees Celsius.
  • Moisture: Need high levels of moisture
  • Time: In the right conditions, will multiply every 10-20 minutes
  • Nutrients: Multiply best on high-risk foods; meat, fish, eggs
  • pH level: Best at a neutral pH, can't survive under pH 3.5
• Yeast is a single-celled fungi that is found in the air and on fruit skin
• Yeast spoils the taste of food, but is not harmful to eat
• • Yeast can survive without air
  • Can’t grow in low temperatures
  • Can’t survive in vinegar
  • Is destroyed at 70 degrees Celsius
• Yeast is used in baking bread - it feeds on the glucose sugar to carry out respiration, which produces CO2
• Moulds are a type of fungus that grow on many foods such as bread, cheese, and meat
• • Moulds like slightly acidic pHs
  • Moulds need moisture
  • Need to be between 20 and 40 degrees Celsius
  • Will be destroyed at 70 degrees Celsius
  • Can survive in the fridge but not in the freezer
• Mould on food is a sign that it isn’t fresh or has been stored incorrectly
• Some mould can cause sickness, allergic reactions, and respiratory difficulties
• Enzymes - biological catalysts
• Enzymes in food cause reactions that give soft spots on fruit and vegetables, and also makes meat smell & taste bad
• By denaturing enzymes (heat, acids, alkalis, salt), you can preserve food
• Enzymic browning - browning of foods by enzymes in the presence of oxygen (oxidation)
• Ways to prevent oxidation/enzymic browning:

  • Adding lemon juice to a fruit salad
  • Blanching veg before freezing
  • Immersing in water
  • Refrigerating/freezing will slow it down
• Starter culture - microorganisms that are used to start the fermentation process in making diary products
• Cheese Making:

  • The culture grows in the milk, converting the sugar lactose into lactic acid
  • This ensures the correct level of acidity and gives the cheese it’s moisture
  • The cheese ripens; the culture gives it a balanced aroma, taste, and texture
  • To get a high-quality cheese, you should choose the right mixture of culture
• Blue cheese: Blue stilton and roquefort

  • Treated with a mould
  • Cheese matures, mould grows
  • Creates blue veins in the cheese
• Soft ripened cheese: Camembert and Brie

  • Fungus called P.Camemberti grows on the outside of the cheese
  • Makes the cheese age from the outside to the inside
  • Forms a soft white crust with a runny inside
• Rind-washed cheese: Époisses and taleggio

  • Washed with brine, as well as other ingredients like beer and wine, which contain mould
  • Makes them attractive to bacteria
  • Ripen inwards, so are runny on the inside like soft ripened cheese
• Probiotic cultures - live microorganisms that are beneficial to the individual when consumed
• Probiotic cultures help improve digestion and protect the immune system.

  Probiotic cultures are classed as a functional food.
• Meat starter cultures are used to make dried products like salami, pepperoni, chorizo, and dried ham
• Yeast:

  • Is used in bread-making as well as making beer and wine
  • Is a microorganism
  • Requires sugar to grow
• Yeast in bread:

  • Produces CO2 which raises the bread dough
  • Creates a stretchy dough
  • Contributes to flavour
• Food poisoning is caused by bacteria multiplying in or on food
• Salmonella:

  • Raw meat, eggs, seafood, dairy
  • Diarrhoea, vomiting, fever
  • Triggered within 12 to 36 hours
  • May be fatal in elderly and babies
• Staphylococcus Aureus:

  • Cooked sliced meat, dairy, anything touched by hand
  • Vomiting, diarrhoea, abdominal pain
  • Triggered within 1 to 6 hours
  • Present in nose, throat, skin, personal hygiene is crucial
• Clostridium Perfingens:

  • Raw and cooked meat, meat products
  • Nausea, diarrhoea, abdominal pain
  • Triggered within 8 to 22 hours
• Clostridium Botulinum:

  • Incorrectly canned meat, fish, or vegetables
  • Paralysis, difficulty breathing, double vision, nausea, vomiting
  • Triggered within 12 to 48 hours
  • VERY rare
• Bacillus Cereus:

  • Cooked rice, pasta, cereals
  • Nausea, vomiting, diarrhoea
  • Triggered within 1 to 6 hours
• Food-borne diseases are caused by pathogenic microbes carried on in food. They do not multiply in the food, but multiply once the food has been eaten.
• E-Coli:

  • Raw meat, untreated milk, water
  • Vomiting, blood in diarrhoea, kidney damage/failure
  • Triggered within 12-24 hours
• Listeria Monocytogenes:

  • Soft cheeses, pate, unpasteurised milk, undercooked meat
  • Range of symptoms: flu, septicaemia, meningitis, and pneumonia
  • Can be set off at any time
  • Can cause miscarriages
• Campylobacter:

  • Meat, shellfish, untreated water
  • Diarrhoea, headache, fever, abdominal pain
  • Triggered within 1 to 11 days

  RAW MEAT AND POULTRY MUST NOT BE WASHED AS THIS SPREADS THE BACTERIA
• Norovirus:

  • Shellfish, raw vegetables, salads
  • Nausea, vomiting, diarrhoea, abdominal pain, fever
  • Triggered within 1 to 2 days
• To ensure safe food is bought:

  • Check for damage to tins, packets, or packaging
  • Check the use by date and best before date
• Use by date - The date that food must be eaten before. If eaten after, it may be dangerous. These are found on high risk foods such as meat, fish, and dairy products
• Best before date - the date when the food is no longer at its best quality, but is still safe to eat. These appear on low-risk foods, which have a long shelf life, such as canned/dried/frozen food products
• Food should be wrapped/covered/kept in a clean container