What is cheese?
Most cheese eaten in Australia is made from the pasteurised milk of cows, sheep or goats. Cheese is generally made by adding a starter culture of bacteria to the milk. These bacteria digest milk sugar (lactose), producing lactic acid, which separates the solids from the liquid in milk. A soft, junket-like curd is formed, leaving the whey, which is drained off.
The curd can be used fresh, or heated, salted, dried, ripened or matured according to the type of cheese being made. For matured cheese, the enzyme chymotrypsin, found in rennet, is also added to the milk. For some types of cheese, the starter culture also contains selected moulds (e.g. white mould for camembert and blue mould for blue vein) or bacteria that produce gas (to form the ‘eyes’ in Swiss-style cheese), or particular flavours, aromas and colours.
There are 4 main groups of cheese categorised according to production techniques and maturity:
- fresh unripened, such as cottage, cream or neufchatel, ricotta, quark, mascarpone and feta;
- soft mould ripened, such as brie, camembert and blue vein;
- firm, such as cheddar and Swiss cheese; and
- hard, such as parmesan and pecorino.
Other types of cheese include stretched curd cheese (e.g. mozzarella and bocconcini) and washed rind cheese (e.g. gruyere).
Cheese as a food
Cheese is one of the most nutritious foods as it is a good source of protein, calcium and a range of vitamins and minerals. Despite being a compact nutrient package, cheese is often avoided because of its fat content. This can vary from about 50 to 85 per cent in mascarpone, which is made from cream, to 35 per cent in cheddar types and 5 to 10 per cent in cottage cheese and ricotta. Nowadays some cheeses are made from milk containing less fat and are labelled as ‘reduced fat’ cheese. In Australia this label means that the cheese contains 75 per cent (or less) of the amount of fat in the regular cheese of the same variety. They are characterised by being milder in flavour. If these cheeses are cheddar types they may still have a fat content of 25 per cent, which should be indicated on the label.
A serve of cheese (40 grams) is a good way to fulfil one of the 2 to 3 daily serves of dairy recommended for most people by the Australian National Health and Medical Research Council. Although rich in calcium, cheeses can be high in saturated fat, so reduced-fat varieties should be chosen where possible. Eat a variety of cheeses, saving the higher fat cheeses for treats.
Take note that low-fat soft cheeses, such as ricotta and cottage cheese, have much less calcium than hard cheeses, such as cheddar, and thus do not count as a full serve of dairy. Ricotta has more calcium than cottage cheese — three times as much per gram — but a regular cheddar cheese has about 10 times more calcium per gram than cottage cheese
Pregnant women and people with a weak immune system should avoid soft, semi-soft and surface-ripened cheeses (e.g. brie, camembert, blue, feta and ricotta), because of the risk of Listeria infection. This infection can seriously affect the unborn child and also people whose immune system is weakened by illness (e.g. cancer and AIDS) or medicines (e.g. after organ transplantation). Hard cheeses (e.g. cheddar and tasty), processed cheese and plain cottage cheese are safer alternatives.
Calcium and fat in cheese
The table below compares the calcium and fat content between samples of different types of cheese.
|Calcium and fat content of sample cheeses|
|Value per 100g cheese|
|Cheese type||Fat (g)||Calcium (mg)|
|Cheddar, cheese spread||24.7||470|
|Cheddar, reduced fat (approx 25%)||24.2||801|
|Cheddar, reduced fat (approx 15%)||15.1||950|