Food Science:  Is it safe?                                                

Food safety covers the way we deal with issues of hygiene in the kitchen.  A clear set of instructions are usually learnt before you start cooking.  Anyone making food for consumption by his or herself or for friends and family the main question relating to the food produced is ‘Is it safe?’


Knowledge about cooking safely is exemplified when students make judgements relating to the cooking time, the types of ingredients being used, the effect of heat on those ingredients, and the changes from raw to cooked.  Understanding the safety aspects of food is fundamental to food preparation.    It is essential to understand the basic food science concepts that relate to safe food. 

FOOD HANDLING            

Food safety must include:

  • The source and origin of the ingredients
  • Cooking temperatures (heat or chill)
  • The storage requirements of the ingredients
  • The shelf life of the ingredients

Food hygiene must be constantly checked:

  • Know and understand and apply hygiene rules
  • Always use correct procedures
  • Clean as you go and after food preparation
  • Avoid cross contamination

Other factors that must be taken into consideration

  • Additives
  • Allergens– note Natasha’s Law
  • High risk food
  • Food safety management systems such as HACCP – especially for catering establishments
  • Seasonality and regionality

Safety and food storage temperatures

Know and check your storage temperatures

Temperature control for food storage

Temperature check

Types of food



Frozen foods

Fridge Temperature     

above 0⁰C  under 5⁰C

Perishable foods

Danger Zone for food safety


5⁰C to 63⁰C

Avoid this zone for perishable foods, meats, shellfish, non-pasteurised cheeses, milk, ready-meals

Ambient temperature (shelf storage) 

18⁰ C – 20⁰ C

(room temperature)

Cans, Packets, Biscuits, Crisps.  Rotate stock


Check your food labels:

It is illegal to sell food after its Use-by date mark.

Best before indicates the product is best quality prior to the date but is safe to eat after that date.


Sourcing food from UK, Asia, Africa and Southern hemisphere means that many products are now available all year round.  Seasonal food is more abundant, usually cheaper and sometimes home grown.


Autumn / winter                                                             





Squash, marrow                                               

Early rhubarb (forced)


New potatoes


Herbs/ chives/                                                                  

Cabbage varieties



Blackcurrants/ blackberries/ autumn raspberries        





Onions/ leeks                                                                   



Rocket and Leaves


Green Beans     

Old Potatoes





Spring Greens








Tomatoes / green tomatoes                                       

Spring onions

Spring onions











Lemons, limes, oranges, tangerines, grapefruits, passion fruits, blueberries, avocado pears, melons, figs, pomegranates, mango, bananas


Food security is the ability of a country to grow, rear or catch enough safe food for its people. Check out the National Food Strategy.


Food miles relates to the miles a food product travels in transit when being imported into the UK.

FOOD INTOLERANCE AND ALLERGIES                                      

Some people have intolerances to foods or parts of food. 

Lactose intolerance means the natural sugar in cow’s milk is not digested and alternatives need to be used, such as oat milk. 

Gluten intolerance means that all foods containing wheat need to be avoided and the gluten-free option used.   

Free-from foods, such as dairy free, nut free, and sugar-free, are clearly labelled to help consumers make the correct choice for their needs.

Diabetics (Type 1 and 2) do not tolerate excess sugar and they need to know how much sugar and starch is contained in food portions so they can make informed choices about what they eat.  

FOOD ALLERGIES for more info go to

An allergic reaction can be very serious and rapidly affect vital systems such as breathing. The response to easting certain food ingredients can trigger the release of histamines and other anaphylatoxins into our bodies which can immediately cause swelling, constriction and shock.

EPI-PENS need to be used immediately in response to symptoms of food allergy.

Allergens are indicated on a food label in BOLD in the ingredients listings.  Errors in this detail of listing is one of the most common causes of food product recalls by the Food Standards Agency.

September 2021 brought about the introduction of Natasha’s Law.

 The law, which comes into effect from October 2021, will require businesses to provide full ingredient and allergen labelling on foods which are pre-packed for direct sale

The 14 allergens are: celerycereals containing gluten (such as barley and oats), crustaceans (such as prawns, crabs and lobsters), eggsfishlupinmilkmolluscs (such as mussels and oysters), mustardpeanutssesamesoybeanssulphur dioxide and sulphites (if they are at a concentration of more than ten parts per million) and tree nuts (such as almonds, hazelnuts, walnuts, brazil nuts, cashews, pecans, pistachios and macadamia nuts).


Micro-organisms are so small they cannot be seen by the human eye.  Some micro-organisms are harmful (Pathogens).   They can multiply to unsafe levels quickly in the right conditions where there is a food supply, warmth, moisture and time.

Pathogens are harmful micro-organisms that can cause food poisoning.  The symptoms are sickness, diarrhoea and stomach ache.

Food poisoning affects babies, young children, pregnant women and elderly people and those people who are unwell with reduced immune systems or those who have allergies.

Campylobacter is one of the most common causes of food poisoning.

Listeria is a food illness that is dangerous for pregnant women as it can harm the foetus.

Other causes of food poisoning are Salmonella and E.Coli.

Staphylococcus Aureus is a harmful bacteria that can live on our skin, in our noses, throats and ears.  If a cook or a chef touches food without washing their hands these harmful bacteria will transfer to the food.

Bacillus cereus is likely to be the cause of food poisoning related to eating rice.  When rice is prepared in advance and reheated there is a risk of food poisoning.  Always stored cooked rice at chilled temperatures and reheat thoroughly checking to break up clumps of rice until everything is piping hot.

Cross-contamination is a likely cause of food poisoning.  Raw food should be stored and prepared separately from cooked food. Keep all food clean, cool and covered (known as 3C’s).


Food additives must be assured for safety before they can be used in food.

The process ensures that

  •      The science on additives is strictly reviewed
  •      The law if strictly enforced
  •      Action is taken quickly if problems arise.

The Food Standards Agency overseas regulation and control of the use of additives in food.

ADVANTAGES of using additives                                                                              

  • Safer food
  • Foods with longer shelf life (keeping quality)
  • Helps consumers with special dietary needs (coeliacs, diabetics)
  • Aids manufacturing             

DISADVANTAGES of using additives

  • Allergens
  • Cost
  • Linked with attention deficit disorder (ADD) in children


Any substance not normally consumed as a food in itself and not normally used as a characteristic ingredient of food.  Used in food products additives must be mentioned I the ingredients list with their name and function e.g. Preservative: Natamycin (E235) in dried sausage

HUNDRED AND THOUSANDS! How additives are numbered

Colours: used to add or restore colour in processed food.  The amounts of some yellow and red colours were limited in 2012

E100 – E 180

Preservatives are important additives used to prolong the shelf life of foods by protecting them against micro-organisms and therefore keeping food safe for longer

E200 – E299

Antioxidants are substances added to prolong the shelf life of foods by protecting them against oxidation, thus preventing fat rancidity and colour changes. Vitamin E is a very effective antioxidant found in fat spreads.

E300 – E322

Emulsifiers & Stabilisers

Emulsifiers make oil and water mixtures combine together, for example in ice creams, salad dressings, spreads and desserts.

Lecithin is a natural emulsifier found in egg yolks.

E481 Sodium Stearol Lactylate is very versatile and used widely in baked goods, toppings, icing

Stabilisers help hold emulsions, preventing separation.

E400 – E495


E420 - E421

More Sweeteners: saccharin, Stevia, Nutrasweet

E950 – E962

Acidity regulators and anti-caking agents:  Potassium, sodium and calcium salts

E500 +

Flavours and flavour enhancers: glutamates

E600 - E 699

Flour treatment agents: they are added to flour or to dough to improve its baking quality.

E 924 - E927

Packaging gases for Modified Atmosphere Pack

E930 - 949

Foaming agents

E990 – E999

Additional chemicals

Humectants : prevent food drying out

Glazing agents:  such as wax

E1000 +








Home cooking is not free from additives.  Many ingredients we commonly use in baking and cooking contain E numbers eg: Flour, margarine, sausages.  Home food does not have to withstand the rigour of transportation nor does it need the shelf life of prepared foods. 


One-off food products made for individuals, families, businesses eg: celebration cakes

Batch production small niche markets to huge batches for retail outlets

Mass production and Continuous flow production, Assembly line production

All food produced or manufactured for sale should have HACCP documentation, or similar such as ASC (Assured Safe Catering) or Safer Food, Better Business (SFBB) for caterers.

HACCP stands for Hazard Analysis and Critical Control Points.

A HACCP document (or similar) should describe the food product, detail the recipe or formula, list the processing stages, lists hazards and their prevention, show a flow diagram, identify intended use, storage requirements and have a review date.  It is very important part of evidence of safe food manufacturing.


Recalls and allergy alerts are shared through   Many food products are recalled because they are incorrectly labelled or contain levels of microbes such as listeria that are too high.

Products are sometimes recalled because they are contaminated by shards of plastic, glass or metal.


A wide range of food products are available all year round.  This is due to manufacturing processes adapting the temperature, water activity, atmosphere, pH (level of acidity) and packaging method to create food products that meet the needs of consumers.


(Iced storage)

Fish / seafood



Drying, Dehydration

Sun drying



Herrings, anchovies



Ultra heat treatment



Modified atmosphere Packaging



Accelerated Freeze Drying


Vacuum Packing



Jam making




Crushed ice is commonly used to store raw fish and seafoods to keep them fresh.


Very low temperatures such as freezing prevents water activity and preserves food for long periods of time. After thawing treat the food as fresh food.


Accelerated freeze drying combines freezing and drying in a process that makes granular products that are lightweight and can be rehydrated with liquid.  Examples: gravy granules, coffee granules, dried milk and sauce granules.


Sterilisation is an intense heat treatment that destroys all microbes and spores.  It can affect flavour giving a cooked taste.  Example: sterilised milk


This uses ultra-high temperature technology that heat for a very short time and then cools and packs immediately in aseptic packs.  This gives at least 3 months safe storage. Example: Milk in cartons


Chilled food such as ready-to-eat, ready-to-cook or -ready-to-serve products are make in high-care zones to ensure good manufacturing practices (GMP) and safe food production.


Dehydration or sun-drying removes water to a level that does not allow microbes to grow and therefore gives a good keeping quality.  Examples: dried peas, beans, lentils.  Vegetables such as potatoes.  Fruits such as tomatoes, apricots, plums (prunes), figs, dates, sultanas, currants.MORE PRESERVATION METHODS

Canning uses intense heat treatment after the food is sealed in the can.  It destroys all microbes and spores.  Once opened store canned food as fresh food.

Pasteurisation is a heat treatment that destroys harmful microbes.  It is always used for fresh milk.  Also, for fruit juices, egg-based mayonnaise, dried egg whites, many yogurts and dairy cream.

Acid marinades are made from vinegars or citrus juices.  It will preserve immersed food such soused herrings or rollmops, pickled onions or other vegetables.

Preserving is used to makes jams, ketchups and chutneys.  It combines heat and sugar in the case of jam, and heat sugar and vinegar (acid) in chutneys and ketchups.  Water activity is limited so the products keep well.

Vacuum packing is used after heat treatment to preserve food.  Examples: ready to eat rice pouches, noodle ready meals, chorizo and other spiced sausages.

Salting makes water unavailable to microbes and therefore it effectively preserves food such as fish. Example salted cod.  The process does affect the flavour of the food.