S-Cool Revision Summary
S-Cool Revision Summary
Food packaging
- Gives food a longer shelf-life.
- Protects food during transportation and storage.
- Keeps food clean from dirt and bacteria.
- Provides information.
- Advertises the product.
- Holds the food in place.
The following table is a list of the different packaging types and their advantages and disadvantages
Material: |
Source: |
Advantages: |
Disadvantages: |
Used for: |
Paper |
Wood |
Can be waxed to make it waterproof, easy to print on, cheap, can be recycled. |
Not very strong. |
Flour, sugar, loose fruit and vegetables. |
Cardboard |
Wood |
Lightweight, easily shaped, easy to print on, can be recycled. |
Soggy if wet. |
Frozen foods, cereals, cakes, fruit juice. |
Glass |
Sand |
See-through, can be coloured, cheap, can be recycled, easily moulded. |
Can break easily. Often needs a paper or plastic film label. Heavy. |
Jam, wine, pickles, milk, cooking sauces. |
Metal (Tinplate and aluminium) |
Ores |
Heat treated to preserve the contents, can be recycled, strong, lightweight. |
Can rip (foil lids), often needs a utensil to open it, needs a paper label. Heat treatment can alter texture and taste. |
Yoghurt lids, tinned foods, bottle tops. |
The UK Food Labelling Regulations 1996 state that the following information must be shown...
- 1. Food Product Name.
- 2. List of ingredients.
- 3. Storage conditions.
- 4. Shelf life.
- 5. Instructions for use.
- 6. Name and address of manufacturer.
- 7. Place of origin.
- 8. Weight or volume.
The following information is voluntary
- 1. A picture.
- 2. Recipe ideas.
- 3. Bar codes.
- 4. Environmental and recycling information.
- 5. Nutritional information.
- 6. Lot or batch mark.
- 7. Opening instructions.
- 8. Special information.
Preservation of food
Food needs to be preserved...
- So that surplus foods from good harvests can be stored and then used in times of shortage.
- So that we can enjoy seasonal fruits and vegetables all year round.
- To enable it to be transported long distances without it decaying (and spillage!).
- To allow it to be stored in the home for long periods without going off.
There are six main ways in which food can be preserved...
- High temperatures
- Canning
- Bottling
- Pasteurisation
- Ultra Heat Treatment (UHT)
- Sterilisation
- Low temperatures
- Freezing
- Chilling
- Removing moisture
- Drying
- Accelerated Freeze Drying (AFD)
- Use of chemicals
- Pickling
- Salting
- Smoking
- Sugar
- Controlling the atmosphere
- Vacuum Packing
- Modified Atmosphere Packaging (MAP)
- Irradiation
Methods of preserving food...
Method and |
Advantages: |
Disadvantages: |
Used for: |
Canning: |
Lasts for many years. |
Can cause changes in colour and texture. Loss of Vitamin C. |
Fish, meat, fruit, vegetables, milk. |
Bottling: |
Lasts for many years. |
Can cause changes in colour and texture. Loss of Vitamin C. |
Fruit and vegetables. |
Pasteurisation: |
Little effect on flavour. |
Not all bacteria killed. |
Milk, cream, orange juice. |
UHT: |
Lasts for several months. |
Changes taste slightly. |
Milk, fruit juices. |
Sterilisation: |
Extends life of milk to about 10 days. |
Gives a creamy flavour and colour. |
Milk, fruit juices. |
Freezing: |
Foods can be frozen for many months. Little loss of vitamins. |
Slow freezing breaks down cells and changes the texture of foods. |
Ready prepared meals, fish, meat, vegetables, fruit, ice-creams. |
Chilling: |
Good colour and flavour kept. |
Short storage life. |
Ready prepared meals, such as Lasagne. |
Drying: |
Last for long periods of time. |
Most Vitamin C lost. Must be kept dry. |
Soups, pasta, beans packet desserts. |
AFD: |
Good colour and flavour. |
Can be expensive. |
Coffee. |
Pickling: |
Long shelf life. |
Very strong flavour. |
Onions, cabbage, olives. |
Salting: |
Long shelf life. |
Food needs to be soaked before cooking. |
Meat, fish, green beans. |
Smoking: |
Adds flavour. |
Kills Vitamins B and C. |
Bacon, cheese, fish. |
Sugar: |
Long shelf life. |
High temperatures in jam making kill Vitamin C. |
Jams, marmalade, crystallised fruits. |
Vacuum packs: |
Retains vitamins. |
Often still needs refrigeration |
Bacon, fish. |
MAP: |
Colour and flavour are good. |
Expensive. |
Meat, salads, minced beef, and bacon. |
Irradiation: |
Delays ripening of fruit and sprouting of vegetables. |
Not in general use. Consumer safety worries. |
Strawberries, vegetables and spices. |
Food poisoning
10 main causes of food poisoning
Cause: | Prevention: |
Preparing food too far in advance. | Prepare food as close to consumption as possible. |
Food cooled too slowly before being refrigerated. | Food must be refrigerated within one and a half hours. |
Food not reheated enough to kill bacteria. | Reheat food until it is piping hot all the way through. |
Contaminated food eaten. | Do not consume food after its eat-by date, and store correctly. |
Food undercooked. | Cook food thoroughly - use a temperature probe. |
Poultry not thawed properly. | Make sure no ice crystals remain. |
Cooked food cross-contaminated by raw food. | Use separate equipment for raw and cooked food. |
Hot food kept warm at less than 63 degrees Celsius. | Check food with a temperature probe. |
Food handlers passing on infection. | Remove jewellery, wear aprons, wash hands, report illnesses, etc. |
Left-overs reheated. | Use quickly, store below 5 degrees Celsius, reheat thoroughly. |
Micro-organisms
There are 3 types of micro-organism...
- Moulds
- Yeasts
- Bacteria
This table shows the most common types of food poisoning bacteria...
Bacteria: | Incubation: | Symptoms: | Found in: | Important points: |
Bacillus cereus | 1-6 hours | Nausea, vomiting, diarrhoea. | Cooked rice, especially if kept warm. | Cool pasta and rice quickly. |
Camploybacter | 2-10 days | Diarrhoea, abdominal pain. | Meat, shellfish, milk, untreated water. | Most commonly reported cause of food poisoning. |
Clostridium botulinum | 12-48 hours | Paralysis. Can be fatal. | Canned food, especially dish, meat and vegetables. Water and soil. | Rare form of poisoning. Bacteria produce spores, which survive high temperatures. |
Clostridium perfringens | 10-24 hours | Diarrhoea, abdominal pain. | Raw meat, cooked meat and products. Soil. | Very common cause of poisoning. Most active at 45-50 degrees Celsius. |
Escherichia coli (E-Coli) | 1-2 days | Diarrhoea with blood, vomiting | Raw meat, untreated milk and dairy products. | Drink bottled water when abroad. |
Listeria monocytogenes | Up to 70 days | Flu symptoms, blood poisoning, meningitis. | Soft cheeses made with unpasteurised milk, pate, cook/chill foods. | Dangerous to pregnant women. |
Salmonella | 12-48 hours | Diarrhoea, fever, vomiting, abdominal pain. | Meat, raw eggs, cream, seafood. | Babies, the elderly and pregnant women should not eat raw eggs. Poultry must be defrosted well before cooking. |
Staphyloccus aureus | 1-8 hours | Vomiting, diarrhoea. | Meat and meat products, eggs. Nose, throat and cuts of food handlers. | Personal hygiene is very important. |
Enzymes
Enzymes can cause undesirable changes in foods that make them unsightly. This is called browning and is caused by the action of an enzyme called polyphenol oxide in the presence of oxygen. Enzymatic browning can be reduced by:
- High temperatures.
- Acidic conditions.
- Other methods.
Symptoms of food poisoning
- Diarrhoea.
- Vomiting.
- Abdominal pain can be very unpleasant and can even cause hospitalisation, or death, for vulnerable groups such as:
- Babies.
- Young children.
- The elderly.
- People whose immune systems are damaged.