Preliminary Operations: Milk Reception and Storage
Raw milk reception at the factory represents the first operation shared among all types of dairy productions. Milk is generally intended to be raw, as delivered by the farmers or collected by tankers at the farms, but today dairies—according to local legislation or individual quality standards—may receive thermized/pasteurized milk, pasteurized cream, evaporated milk, skimmed UF/MF retentates, butter, butteroil, and any other milk component—either liquid, concentrated, or dry.
Quality control is carried out before unloading the tankers to verify the milk supply is in compliance with legal and proprietary quality and food safety standards. These requirements are generally formalized in a contract undersigned by the first buyer and the farmer. Milk is then unloaded to be passed through stainless steel or cloth filters before being eventually cooled down to 4°-6°C and stored in isothermic/refrigerated silotanks.
Traditional raw milk cheese productions involving a chemical/microbiological “maturation” at temperatures higher than 8°C (e.g., extra-hard POD cheeses like Grana Padano and Parmigiano Reggiano) are an obvious exception to this rule.
Milk-storing practices before further transformation may differ from one dairy to another, according to the end-product types, daily milk volumes, factory size, and local habits, for example.
Some big dairy companies skim all the milk received in their factories and store only pasteurized skim milk and cream at the temperature of 4°-6°C. Skim and cream are then recombined in the correct proportion to prepare the milk for further processing.
Other dairies store only raw chilled milk that is submitted to heat treatment and standardization only at the moment of preparation of the target milk recipe. In the case of large cheese factories not working 24/7, raw milk received during weekends is often thermized or pasteurized inline at reception and refrigerated until use on the following Monday.