Q. Spoilage of butter?
Butter, which has a high content of fat, is subject to rancidity and microbial spoilage due to contaminated cream from which it has been prepared. The dominant microorganisms responsible for spoilage are the psychrotrophic bacteria due to the fact that butter is usually stored under refiigeration conditions. The putrid, proteolytic fruity flavours in butter are caused by the psychrotrophic bacteria. Pseudomonas fluorescens and Pseudomonas fiagi are Bssociated with the fruity odour in butter, They are both proteolytic and lipolytic i.e., they decompose proteins and fats. The presence of these organisms is due to the post pasteurization contamination through water and processing equipment. Tlie surface taints and putrid flavours are caused by Altermonas pumfaciens and Pseudomonas putrefaciens which grows on the surface of butter.