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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Today we are going to cover:
Harmfull chemicals in food
Methods to keep food safe
How to eat healthy
There are 5 different types of food additives you need to be familiar with
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.
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 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.
intolerances e.g. gluten (in wheat)
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.
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.
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).
FSA (food standards agency) is a safety watchdog responsible for:
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.
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.
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.
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 is a process which continues to recycle nitrogen within the environment.
See Nitrogen cycle sheet.
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 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.
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.
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.
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.
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.
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.
in C2 we have already met
polymers… these huge
molecules are made up of
much smaller units during
sugars are molecules made of carbon, oxygen and hydrogen
The monomers (amino acids) are made from carbon, oxygen, hydrogen AND nitrogen
(shown by the blueatoms above!)
e.g. starch and protein
are broken down to
amino acids which
can be transported
in the blood
Absorption of the sugars
and amino acids occurs
in the small intestine
Skin and hair
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
Type 1 diabetes
Type 2 diabetes
Not enough insulin
OR the body no longer
responds to it
injections of insulin
Controlled by diet and