Cheese

The key ingredient to watch out for in cheese is animal rennet. Food labelling laws in the UK mean that labels do not always require processing agents to be listed, of which animal rennet is one. Rennet is an enzyme used to set cheese during the making process. Stirred into a vat of cultured milk, it causes the milk to coagulate and separate into solids (curds) and liquid (whey). The curds are turned into cheese. There are two main types of rennet, animal rennet and vegetarian rennet.

• The traditional source of animal rennet is the stomach lining of calves. The lining contains chysomin, a naturally occurring enzyme, which helps digestion and milk absorption.
• The enzyme is extracted from the stomach lining of the slaughtered calf, by washing and drying the lining. It is then softened in a solution of brine, or boric acid, for four-to-five days, before being ready to use.

• Vegetarian rennets are either vegetable-based (made from plants such as figs, nettles and thistles), microbial (produced using moulds and fungi sources) or made using genetically modified rennet.
• A high percentage of hard cheese made in the UK is produced using chymosin produced in genetically modified organisms (GMO’s). For example, chymosin can be made by the genetic modification of the yeast Kluyveromyces lacti. To do this, the genetic code, or DNA, for chymosin is isolated from calf cells. This DNA acts as a template. A copy is produced and is inserted into yeast cells, which are cultivated and allowed to grow in a suitable environment. The chymosin produced by these cells is identical to the animal protein and the cheese itself is not made using a GMO but rather a product of this, the enzyme.

• Paneer and cottage cheese is traditionally made without rennet and is instead coagulated with an acidic ingredient like vinegar or lemon juice.
• Artisan cheeses from specific areas may be vegetarian. Cornish Yarg, which is wrapped in nettles, usually uses vegetarian rennet, although their cheeses for the US export market may contain animal rennet. Colston Basset Stilton from Nottinghamshire and Lord of the Hundreds, an English ewes’ milk cheese, are usually made using vegetarian rennet.
• Some British Protected Designation of Origin (PDO) and Protected Geographical Indication (PGI) cheeses are vegetarian. However, PDO or PGI status does not guarantee that a cheese will always be suitable, so always check with the manufacturer. At the time of writing, vegetarian cheeses with PDO or PGI status include: Beacon Fell traditional Lancashire Cheese, Dorset Blue, Dovedale Blue, Orkney Scottish Island Cheddar, Single Gloucester, Staffordshire cheese, Swaledale cheese, Swaledale ewes cheese, Traditional Ayrshire Dunlop, Traditional Welsh Caerphilly and Yorkshire Wensleydale.

• Manufacturers are not required by law to label products for vegetarians. If they do apply labels, they do so voluntarily. This is why labelling can be inconsistent and unclear. Look for a ‘suitable for vegetarians’ or ‘V’ label to be sure a product is veggie-friendly.
• For complete confidence in a cheese being vegetarian or vegan, look out for the Vegetarian Society Approved vegetarian and vegan trademarks.