Word 2007 .docx version. Dairy industries Milk.

Milk is a food containing Sugar Fats Proteins Vitamins Minerals (such as calcium) Milk is processed to: Make it last longer Kill germs that might cause disease make it healthier Milk processes are: Evaporated (condensed) milk Much of the water in the milk is evaporated out The heat treated milk is put in an evaporator, where it is concentrated it can be put in cans and lasts for a very long time Skimmed milk The fat is taken out of the milk the milk with less fat is healthier for people on diets. Semi-skimmed milk Most of the fat is taken out of the milk but some is left this is healthier for people on low fat diets but tastes better than skimmed milk. Pasteurised milk the milk is heated to 72ºC for 15 seconds then cooled rapidly to under 5ºC Pasteurisation destroys most disease-causing microbes. This milk will keep for 5 days in a fridge UHT milk. This milk is heated to over 135ºC for 2-5 seconds. This changes the taste of the milk UHT treatment preserves milk and prolongs shelf life by destroying all the microbes which cause milk to sour. It will keep at room temperature in a sealed container for a long time

• Tests are carried out on milk for bacteria (germs) to test for fitness to drink.

• The resazurin test is used to demonstrate the presence of bacteria.
• Blue resazurin is added to the milk
• The milk is heated to 40ºC for 20 minutes
• If the resazurin turns pink the milk is unfit to drink

Yoghurt.

• Bacterial cultures can be added to pasteurised milk to make yoghurt.

• Making yoghurt is a method of preserving milk.
• Bacterial cultures are added to the milk.
• They convert sugar to an acid which helps clot the protein to thicken the milk
• The acid and the bacteria help preserve the milk
• They also give the yoghurt its flavour

Cheese. To make cheese: The milk must be clotted To do this rennet is added: The rennet clots the protein in milk to make curds The curds are used to make the cheese. Rennet can be obtained from a variety of sources: from calves’ stomachs or from genetically engineered fungi grown in fermenters (this is called genetic modification or GM). The left over liquid is called whey.

Type of Rennet Advantage Disadvantage Natural Not a GM food A lot of calves have to be killed to produce a little rennet. The cheese is not suitable for vegetarians Bioengineered (GM) Can be eaten by vegetarians No calves are killed Some people will not eat GM foods

• Bacterial cultures are also added to the milk.
• They convert sugar to an acid which helps clot the protein and also affect the flavour of the cheese.
• The longer the cheese is left to mature the stronger the taste becomes.

Environmental Impact

• Cheese making can affect the environment
• Waste whey used to be dumped into rivers.

• In rivers it can cause pollution which kills plants and fish

• Whey is a waste product which can be upgraded.

• Whey can be used as a food source for growing yeast in fermenters to produce a creamy alcoholic drink.
• Whey can also be used to feed animals.

Yeast-based industries Yeast Yeast is a simple fungus It is very tiny and oval shaped under a microscope Yeast eats sugar and makes alcohol and carbon dioxide This is called fermentation Bread Yeast is used in bread dough. The yeast makes bubbles of carbon dioxide in the dough This causes the bread to rise The bread becomes light and fluffy Beer In beer making yeast converts sugar into alcohol and carbon dioxide. The type of yeast, the temperature and the fermentation time affect the alcohol content of the beer produced. Cask conditioned beer. Cask conditioned beer (real ale) the yeast is not removed at the end of fermentation As a result fermentation and carbon dioxide production continue in the cask. The “fizz” in the beer is entirely natural Brewery conditioned beer. Yeast is removed at the end of fermentation Additional carbon dioxide is added to make it fizzy.

Fermented milk drinks

• An enzyme can be added to milk to convert some sugar to lactic acid.
• Lactic acid is sour flavoured and helps thicken the milk
• Yeast is also added and converts some sugar to alcohol and carbon dioxide.
• The product is a fermented milk drink.
• Both the yeast and the enzyme can be immobilised so that they can be separated from the end-product and can be used again.
• In immobilisation the yeast and enzyme are caught in jelly beads
• The milk is passed slowly over the beads to let the yeast and enzymes work.

Flavouring and food colouring

• Flavourings and food colourings can be produced from yeast.
• Crisps can be flavoured
• Salt is added to the yeast and it is then heated to make the flavour
• Salmon flesh is coloured red using yeast products

Environmental impact

• Waste from yeast-based industry can have the same effect on rivers as whey
• In rivers it can cause pollution which kills plants and fish
• Yeast-based industries upgrade their waste by:
• Producing animal feeds such as cattle cake.
• Yeast is involved in the upgrading of waste whey to make animal feed.

Detergent industries

Production of biological washing powders and liquids.

• Biological washing powders and liquids use enzymes to help cleaning
• Enzymes are chemicals that reduce the temperature at which cleaning can be done.
• The enzyme digests  the stains
• Most stains are biological like sweat and food
• The enzyme breaks the stain down (digests) into chemicals that dissolve easily
• It is claimed that this saves energy and results in less damage to delicate fabrics.
• Washing at lower temperatures reduces fuel consumption
• This reduces the pollution caused by the burning of fossil fuels in power stations.
• Enzymes are produced in large quantities by bacteria cultured in industrial fermenters.
• Enzymes are covered in a harmless coating to prevent allergic reactions which can cause skin rashes and eczema.

Environmental impact.

• Detergents in waste water can be toxic to wildlife.
• Detergents contain other chemicals which can increase the growth of algae (minute plants) in lakes and rivers
• When algae die this can have the same effect as whey released into rivers.
• To prevent this:
• Manufactures try to reduce the chemicals in detergents,
• sewage works removing these chemicals before releasing water into the environment.

Pharmaceutical industries

pharmaceuticals are medicines diseases are caused by germs: bacteria viruses funguses and yeasts Antibiotics Antibiotics are produced naturally by fungi originally isolated from soil by Alexander Fleming. The antibiotic he discovered is Penicillin which is still in use today Antibiotics destroy and prevent the further growth of bacteria. Antibiotics only act on bacteria and not on viruses So they will not work on the common cold or other virus diseases Different antibiotics are effective against different bacteria. We need a range of antibiotics to treat all the bacterial diseases Antibiotics are produced commercially in automated industrial fermenters. Antifungals. Antifungals are chemicals which limit fungal growth. They are used to treat fungal infections such as athlete’s foot and thrush.

Modern production methods

• Huge fermenters are used to produce medicines
• In the fermenters micro-organisms have been genetically engineered to produce the desired product.
• Genetic engineering means changing a micro-organism to produce something useful
• This means it is easier to manufacture and purify the final product.
• Computer-control technology is used to monitor and adjust growing conditions e.g. temperature, pH, oxygen levels.

Environmental impact.

• Over-use of antibiotics can lead to bacteria developing resistance to the antibiotics.
• This means there are some diseases that are very difficult to cure
• MRSA in hospitals is an example of this
• Up to 100,000 patients fall victim to some form of infection in hospital every year, in some cases leading to amputation and death
• It is estimated that MRSA contributed to the deaths of over 800 people in the UK last year
• Treatment costs drain up to £1 billion from the NHS every year. (see this article from the Guardian Monday August 2, 2004 )

Put a tick in each box when you can answer each question

Check Tests:

Can you give the meaning of these words?

	Evaporated milk		fermentation
	Skimmed milk		Cask conditioned
	Semi-skimmed milk		Brewery conditioned
	Pasteurised milk		Lactic acid.
	UHT milk.		immobilised
	bacteria		Enzymes
	resazurin		digests
	rennet		pharmaceuticals
	curds		Antibiotics
	whey		Penicillin
	Yeast		Antifungals
			Genetic engineering

Can you explain about these?

	The five things in milk		The effects of dumping yeast in rivers
	Two reasons why milk is treated		How to measure oxygen demand
	How milk is tested using resazurin		How waste yeast can be upgraded
	How yoghurt is made		How do biological washing powders work
	How cheese is made		How do biological powders benefit the household
	One advantage and one disadvantage of using genetically engineered rennet		How do biological powders benefit the environment
	One advantage and one disadvantage of using natural rennet		How can washing powders harm the environment
	Why bacteria are needed to make cheese		How is damage to the environment kept as small as possible
	The effect of whey on rivers		What do antibiotics do?
	How whey can be upgraded		Who discovered antibiotics
	How bread is made		How do you decide which antibiotic to use
	How beer is made		What does an antifungal do
	How fermented milk drinks are made		Name two fungal diseases
	How to immobilise yeast		What is meant be genetic modification (GM)
	The advantages of immobilising yeast		How does a fermenter work
	How yeast can be used as colouring		How is a fermenter controlled
	How yeast can be used as a flavouring		What problem has arisen with the use of antibiotics