A modified ultra high temperature treatment for reducing microbial lipolysis in stored milk.

Abstract

Cultures of Pseudomonas P46 grown in whole milk to contain approximately 2 X 10(7) or 1 X 10(8) viable cells ml-1 before ultra high temperature (UHT) treatment (140 degrees C for 5 s) demonstrated near linear increases in the concentration of short-chain free fatty acids (FFA) during storage at 20 degrees C. However with 5 X 10(6) cells ml-1 before UHT heat treatment there was no detectable increase in these FFA levels over a 6-month storage period. A novel heat treatment (140 degrees C for 5 s followed by 60 degrees C for 5 min) reduced the rate of production of volatile FFA to less than 10% of the rates achieved after the normal UHT treatment.