Food matters
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Today we are going to cover: Food additives Harmfull chemicals in food Methods to keep food safe How to eat healthy. Food Matters. 21/03/11. Food additives. There are 5 different types of food additives you need to be familiar with

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Food Matters

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Food matters

Today we are going to cover:

Food additives

Harmfull chemicals in food

Methods to keep food safe

How to eat healthy

Food Matters


Food additives

Food additives

There are 5 different types of food additives you need to be familiar with

  • Food colourings- these make food look mpore attractive and more appetising. Often used in soft drinks and sweets.

  • Flavourings and flavour enhancers- flavourings are added to a food to give it a new/ different taste. Flavour enhancers are added to food in order to enhance the original flavour the food had. Eg. Make a banana taste more like a banana. Usually found in ready meals.

Food matters

3. Artificial sweetners(like saccharin) are used in things like dies foods and drinks. They usually taste sweeter than sugar, so you don’t need to use as much.

4. Antioxidants- these stop foods from reacting with oxygen and going off. Oxygen can turn fat in food into a nasty tasting and smelling substance. Antioxidants are added to food that contain fat.

5. Preservatives- These are added to food to stop harmful bacteria growing on them. Means food can be stored for longer.

Emulsifiers and stabilisers additives

Emulsifiers and Stabilisers (additives)

These help oils and waters mix correctly. When oil is added to water they separate out.

Emulsifiers are added to foods to help oil and water mix. Stabilisers keep the oil and water together once mixed.

Emulsifiers and stabilisers are added to food which contain water and oil, For instance mayonnaise, salad dressing, vegetable spread (Flora).

Food additives are regulated

Food additives are regulated

Food additives are regulated by the Food Standards Agency.

Food additives need to pass a safety test, to make sure they wont cause long term effects. If they pass they will be given an E number which means they have passed the standards set by the European union.

E numbers do however still cause problems to some people. Allergic reactions, asthma and hyperactivity.

Harmfull chemicals in food

intolerances e.g. gluten (in wheat)

Harmfull chemicals in food

Allergies e.g. peanuts

Certain fungi can grow on nuts and harvested cereal crops. These produce a toxin called

Aflatoxin. Aflatoxin cannot be gotten rid of

Cassava: If roots are eaten lethal cyanide in the liver is produced. Also the same can be said for red kidney beans if they are not cooked properly.

Difference between intolerance and allergy

Difference between intolerance and allergy

An Allergy is where a person gets an allergic reaction (e.g rash) when exposed to a particular food. Can cause windpipe to contract and lead to death. Example peanut allergy

An Intolerance (example wheat) is where a person can eat a food, no reaction is shown, however person cannot digest the food.

Don t forget mushrooms can be poisonous eat and die

Don’t forget mushrooms can be poisonous. Eat and die!

Burning foods can also be bad

Burning foods can also be bad

Burning foods, or cooking foods at very high temperatures can cause dangerous chemicals, HAs and PAHs to be formed. These can alter your DNA, causing cancer.

Chemicals left over from farming (pesticide residue) can also cause long term problems in humans (e.g. Parkinson's).

How can i avoid these harmful chemicals

How can I avoid these harmful chemicals?

FSA (food standards agency) is a safety watchdog responsible for:

  • clear labelling on foodstuffs, offers advice on food safety, diet farming and hygiene

  • Food sampling programmes, to check for harmful chemicals.

    Scientific advisory committees carry out risk assessments to set safe limits. These advise the government on what is safe to eat and what isn’t.

Eating healthy

Eating healthy

Individuals can make their own decisions on what they want to eat.

People who want to reduce their exposure to potentially harmful chemicals can take several steps:

1)Choose food produced in a way which minimises the amount of artificial chemicals applied to it.

2) Wash the foods carefully

3)Store and cook the food in the way recommended on the packaging.

Danger of processed foods

Danger of processed foods

Processed foods contain high amounts of sugar, fat, salt and other additives.

However a lot of processed foods are convenient and don’t take a lot of preparation or cooking.

Task what could be going on here explain

Task: What could be going on here? Explain.

  • Robbie cooks fatty steaks on a BBQ. He puts a lot of coal in and gets a good flame going.

  • Bert is an eco warrior, he collects food from the forest to eat.

  • Flora has a rash and breathing problems when she eats peanut butter sandwiches.

Food matters

C3 Revision lesson 2Today we will cover: Nitrogen cycle, Organic and intensive farming, natural polymers, digestion, insulin and diabetes.



As plants grow they take in oxygen, nitrogen and carbon through their roots and leaves.

When plants die and decompose most of these elements are recycles into the soil.

If we farm (harvest) the plant and its products we are effectively removing this recycling ability.

This is why farmers need to add nutrients to their soil to make sure that plants have enough nutrients to grow each year.

The nitrogen cycle

The nitrogen cycle

The nitrogen cycle is a process which continues to recycle nitrogen within the environment.

See Nitrogen cycle sheet.

Organic and intensive farming

Organic and intensive farming

As we said removing crops removes potential nutrients from the soil.

Organic farming products are generally more expensive in the supermarkets. This is because organic farming tends to require more manual labour.

Organic farming

Organic farming

Organic farming relies on the farmer not using artificial fertilisers. They use natural substances instead, like animal manure, compost and even human sewage.

Manure and sewage feed into the nitrogen cycle, being broken down by nitrifying bacteria.

Organic farming legumes

Organic farming- (legumes)

Some legumes (pea’sand clover) have root nodules on their roots. These root nodules contain Nitrogen fixing bacteria which can fix nitrogen from the air into nitrates in the soil.

Organic farmers may use crop rotation, where for one year they may just grow legumes in one of their fields. These legumes will then add nitrates to the soil for them.

Intensive farming

Intensive farming

This method relies on artificial fertilisers which are produced in factories.

These artificial fertilisers contain pure chemicals so it is easy to add just the right amount. They can also use small amounts as it is a pure chemical.

Also because the fertilisers contain pure nitrates you don’t need to rely on the nitrifying bacteria.

Pest control intensive farming

Pest control- Intensive farming

Pests and diseases are a pain for farmers.

Intensive farming relies on chemicals such as pesticides and herbicides which kill pests and weeds. Fungicides are also used which kill fungi infections on the plants.

Chemical pesticides kill all animals which could be classed as a potential pest, not just the ones you want killed. So you may end up killing pests that are beneficial in the future.

Pest control organic farming

Pest control- Organic farming

Organic farmers use biological control to kill pests on their crops. This is where you use a pests natural predator to get rid of the pest. For instance if a farmer has lots of aphids (green fly) on their crops they will use ladybirds to naturally hunt down and eat the aphids.

Leaving hedge rows at the edges of field provides a home for these natural predators.

Food matters

Organic farmers need to follow certain rules set out by the UK government.

These say that they cannot use artificial fertilisers, chemicals, and pesticides. They also cannot use growth hormones on any of their plants or animals.

Food matters

in C2 we have already met

polymers… these huge

molecules are made up of

much smaller units during


Polymers don t have to be synthetic

Polymers don’t have to be synthetic

Polymers made from sugars

Polymers made from sugars

sugars are molecules made of carbon, oxygen and hydrogen



Polymers made from amino acids

Polymers made from amino acids


The monomers (amino acids) are made from carbon, oxygen, hydrogen AND nitrogen

(shown by the blueatoms above!)

Digestion of food

Digestion of food

  • natural polymers

    e.g. starch and protein

    are broken down to

    soluble sugars/

    amino acids which

    can be transported

    in the blood

    Absorption of the sugars

    and amino acids occurs

    in the small intestine

What are the amino acids used for

What are the amino acids used for?

  • to build new proteins for growth and repair


Skin and hair


What happens if there are too many amino acids in our bodies

What happens if there are too many amino acids in our bodies?

Kidneys remove the urea from

the blood and send it to the


Excess amino acids are

broken down to form

Urea by the liver

Waste is excreted



  • Vital as an energy source for respiration

  • Found in large amounts in processed foods

  • Are absorbed quickly into the blood stream

  • Insulin (a hormone produced by the pancreas) controls the uptake of sugars into cells (so lowers blood sugar level!)

Blood sugar levels out of control

Blood sugar levels out of control

Poor diet

  • A condition known as diabetes


Type 1 diabetes

Type 2 diabetes

Not enough insulin


OR the body no longer

responds to it

Pancreas stops



Requires regular

injections of insulin

Controlled by diet and


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