Chosing in-countainer pasteurization for dairy products

To ensure microbiological safety before retail and consumption, liquid or semi-liquid products such as dairy products are subjected to pasteurization. It is a mild heat treatment using temperature under 100°C.  The temperature and the length of time used depend on the type of the product, number and heat resistance of microorganisms and enzymes present in the dairy product. The main objective of the pasteurization is to destroy microbial and enzymatic activity in the product. Today, there are three types of pasteurization: Low Temperature Long Time (LTLT) – not used commercially these years -, High Temperature Short Time (HTST), Ultra High Temperature (UHT) and in-container pasteurization using a retort.

Compared to the three other types, the in-container pasteurization is known to be more flexible and simple to put in operation. It is also chosen by dairy food industries for its economic benefits. It requires indeed less initial capital but also less recurring expenditure. It is already widely used for condensed milk in cans for example. 

To obtain healthy dairy products with in-container pasteurization, an agitation of the products in the autoclave is needed. It allows to avoid undesirable reactions, particularly browning ; this is the result a complex chemical reaction named Maillard, a nonenzyme glycation. In the case of milk, the lactose reacts with the free amino acid side chains of milk proteins. It causes the formation of melanoidins responsible of the brown colour of the milk thatdramatically decreases its commercial value.

The common solution to prevent these reactions and produce high quality dairy products is the rotary retort. For better temperature homogeneity, Steriflow uses a cascading pre-heated water process for its rotary retort instead of water spray or steam/air process. 

Steriflow also developed another agitating process for the pasteurization of dairy products, similar to rotation but at a more advantageous price. The Steriflow Dali, with its low-frequency horizontal shaking, is perfectly suited to bottled milk pasteurization.