It is believed that cheese evolved in the ‘Fertile Crescent’ between the Tigris and Euphratres rivers, in Iraq, some 8000 years ago during the “Agricultural Revolution”, when certain plants and animals were domesticated. Among the earliest animals domesticated were goats and sheep; being small, gregarious and easily herded, these were used to supply meat, milk, hides and wool. Cattle were more diffi cult to domesticate; wild cattle were much larger and more ferocious than modern cattle and were also less well suited to the arid Middle East than goats and sheep. Apparently, cattle were used initially mainly as work animals and were not used as a major source of milk until relatively recently. The nutritive value of milk produced by domesticated animals was soon recognised and milk and dairy products became important components of the human diet. Milk is also a rich source of nutrients for bacteria which contaminate the milk and grow well under ambient conditions.