© BRITISH NUTRITION FOUNDATION 2012 Case study – part 2 Dairy farming

© BRITISH NUTRITION FOUNDATION 2012 Learning objectives To recall the key stages in milk processing. To learn about Cheddar cheese production.

© BRITISH NUTRITION FOUNDATION 2012 Case study For three generations a family have farmed dairy cows and produced Cheddar Cheese in the West country. On this farm, each cow produces about 7,000 litres of milk per year, which in total supplies the cheese dairy with just over 7 million litres of fresh milk to be made into traditional farmhouse cheese. This volume of milk equates to an annual cheese production of 6,000 tonnes. Find our more …

© BRITISH NUTRITION FOUNDATION 2012 Milk processing After the milk has been delivery from the dairy, it is pasteurised. Pasteurisation is a process used to kill harmful microorganisms, such as certain pathogenic bacteria, yeasts and moulds, which may be present in the milk after initial collection. This process extends the shelf life of milk. The basic process for whole milk involves heating the milk to a temperature of no less than 71.7ºC for 25 seconds. This process is known as High Temperature Short Time (HTST). The milk is then cooled for packing, storage and transportation.

© BRITISH NUTRITION FOUNDATION 2012 Homogenisation Homogenisation of milk involves the milk being pumped at very high pressures through narrow tubes, breaking up the fat globules in order for these to disperse through the liquid. This process produces milk of a uniform composition and palatability, without removing or adding any constituents. Most milk available for purchase is homogenised.

© BRITISH NUTRITION FOUNDATION 2012 Packing The milk is then packaged into bottles and labelled. The packaging helps to increase the shelf-life of the milk. The milk is then distributed to supermarkets and shops for sale.

© BRITISH NUTRITION FOUNDATION 2012 Find out more about milk To find out more about milk, access the From grass to glass – the journey of milk poster. Click here to download the poster

© BRITISH NUTRITION FOUNDATION 2012 Cheese production In this cheese factory, up to 25,000 litres of milk can be delivered from dairy farms at any one time. The milk is unloaded and literage is checked before the milk is transferred into silos. Find our more …

© BRITISH NUTRITION FOUNDATION 2012 Pasteurisation The first process the milk goes through is pasteurisation. Pasteurisation reduces the number of spoilage microorganisms and provides a good environment for the starter cultures to grow. Milk is cooled in a vat after pasteurisation to 32 °C, an ideal temperature for the starter culture to grow.

© BRITISH NUTRITION FOUNDATION 2012 Curdling A starter culture, similar to freeze dried natural yogurt, is then added to the pasteurised milk. This begins to acidify the milk. The curlding step allows the bacteria to grow and begin fermentation. Rennet, an enzyme that acts on the milk protein caesin, is added and the milk coagulates, forming lumps. The milk is mixed and then left to settle, while the junket forms, where the milk curdles and separates into curds and whey.

© BRITISH NUTRITION FOUNDATION 2012 Cooling tables and draining whey The curds and whey run from the cheese vat onto the cooling tables. The cooling tables are used to: 1) cool the curds and whey; 2) separate the curds from the whey. The whey is drained off for further processing where cream is removed from the whey by centrifuge and made into butter. Protein is also extracted from the whey for different ingredients. In addition, lactose is removed from the water and then used for animal feed.

© BRITISH NUTRITION FOUNDATION 2012 Cheddaring The mixture is moved around on the cooling tables allowing the whey to drain out through a central perforated channel. As the liquid is drained off a solid mass is created, called curd mats.

© BRITISH NUTRITION FOUNDATION 2012 Cheddaring The curd mats are cut into sections and piled on top of each other and turned periodically. This step is called ‘cheddaring’. The protected name is West Country Farmhouse Cheddar and the conditions are that it is: made in the four Counties (Cornwall, Devon, Summerset, Dorset); produced on a farm, using in part or whole milk produced on that farm supplemented where necessary by other locally produced milk; cheddared by hand; matured for at least 9 months.

© BRITISH NUTRITION FOUNDATION 2012 Salting Around 1,900 kg of cheese can be made on the cooling table within an hour. The curd pieces are fed into a mill and sliced into pieces about half the size of a thumb. This ensures the salt can be uniformly mixed throughout the curd. Salt is added to act as a preservative and prevent the cheese from going rancid during the maturing process. It also adds flavour to the cheese.

© BRITISH NUTRITION FOUNDATION 2012 Cheese blocks The mixture is then taken into a six metres high tower to form rectangular shaped cheese blocks, weighing 20 kilograms each. After confirming the weight, these blocks are individually identified, ensuring traceability. Following this, the blocks are vacuum packaged and encased in six or seven wooden boards. They are then taken to the cool room and are chilled to a temperature of 10-12°C.

© BRITISH NUTRITION FOUNDATION 2012 Cheese ripening In the cool room, acidification of cheese continues at a much slower rate during this period known as ripening. When it is time to select the cheese, the grader decides which cheeses are the best eaten young and which should be left to ripen (for up to 18 months) developing the special features and flavours associated with West Country Farmhouse Cheese.

© BRITISH NUTRITION FOUNDATION 2012 Cheese packaging The final stage in cheese production is slicing and packaging. The cheese blocks are then cut into specific sizes, packaged and labelled. These products are sold via retailers large and small throughout the UK, as well as in the farm shop.

© BRITISH NUTRITION FOUNDATION 2012 By-products from the farm In addition to the cheese, there are other products produced on the farm. The male calves are kept to form a herd of beef animals supplying quality meat to the farm shop. Arable crops, including wheat, barley, oats, oilseed rape and maize is grown. Some of the grain is used to feed the stock, such as dairy cows and pigs, while the rest is sold. Pigs are fed on whey from the cheese production and cereals grown on the farm.

© BRITISH NUTRITION FOUNDATION 2012 Slurry lagoon The farm has a slurry lagoon which stores the slurry, a mixture of dairy cow manure and the water used to wash out the cow barn. This is used as fertiliser and spread over the fields at certain times of the year. The fields are used for grazing or growing crops such as wheat and barley.

© BRITISH NUTRITION FOUNDATION 2012 Quiz Take the quiz. EndTake the quiz

© BRITISH NUTRITION FOUNDATION 2012 Question 1 True or false? Pasteurisation is a process used to kill harmful microorganisms, such as certain pathogenic bacteria, yeasts and moulds, which may be found in the milk after initial collection. A. True B. False

© BRITISH NUTRITION FOUNDATION 2012 Question 1 Correct – well done! Next question

© BRITISH NUTRITION FOUNDATION 2012 Question 1 Sorry, that is not correct. Try againNext question

© BRITISH NUTRITION FOUNDATION 2012 Question 2 What is homogenisation? A. Milk is heated and cooled very quickly to pasteurise the milk. C. Milk is sorted into different types according to fat content. B. Milk is pumped at high pressure to disperse the fat through the milk. D. The dairy cows are grouped according to milk yield.

© BRITISH NUTRITION FOUNDATION 2012 Question 2 Correct – well done! Next question

© BRITISH NUTRITION FOUNDATION 2012 Question 2 Sorry, that is not correct. Try againNext question

© BRITISH NUTRITION FOUNDATION 2012 Question 3 Which enzyme is added to the milk and acts on the milk protein caesin, causing it to coagulate, forming lumps. A. Curdle C. Amylase B. Junket D. Rennet

© BRITISH NUTRITION FOUNDATION 2012 Question 3 Correct – well done! Next question

© BRITISH NUTRITION FOUNDATION 2012 Question 3 Sorry, that is not correct. Try againNext question

© BRITISH NUTRITION FOUNDATION 2012 Question 4 Which of the following is removed and drained away when making Cheddar cheese? A. Curds B. Whey

© BRITISH NUTRITION FOUNDATION 2012 Question 4 Correct – well done! Next question

© BRITISH NUTRITION FOUNDATION 2012 Question 4 Sorry, that is not correct. Try againNext question

© BRITISH NUTRITION FOUNDATION 2012 Question 5 What is added to act as a preservative and prevent the cheese from going rancid during the maturing process? A. Fat C. Salt B. Sugar D. Whey

© BRITISH NUTRITION FOUNDATION 2012 Question 5 Correct – well done! End

© BRITISH NUTRITION FOUNDATION 2012 Question 5 Sorry, that is not correct. Try againEnd

© BRITISH NUTRITION FOUNDATION 2012 British Nutrition Foundation High Holborn House High Holborn London WC1V 6RQ Telephone: Fax: Web :