Strategies for minimizing sporeformers and spores during milk powder processing

S. Anand

Document Type

Abstract

Publication Date

2019

Location

2019 American Dairy Science Association Annual Meeting: Cincinnati, Ohio

Publisher

American Dairy Science Association

Journal

Journal of Dairy Science

Volume

102

Issue

Suppl.1

Pages

100-101

Language

en.

Keywords

sporeformers, spore, skim milk powder

Abstract

High counts of thermoduric sporeformers and their endospores in milk powders offer a major challenge in their marketability and utilization in further processing and product development. These organisms reduce the shelf life of products and cause many spoilages. This presentation includes strategies that we researched in our lab to minimize sporeformers in skim milk powders. In a typical dairy processing plant, the first step starts at the raw milk reception and storage stage. Based on the spore former population dynamics, regression models and contour plots were developed, which helped us choose specific temperature and storage duration combinations that would keep the population more toward vegetative cells. Our other research indicated that having a shift toward vegetative cells would result in lower biofilms on plate 101J. Dairy Sci. Vol. 102, Suppl. 1 heat exchangers (PHE) during pasteurization. Such biofilms are a source of contamination of milk being pasteurized. Certain stainless steel modifications were also tested for reduced biofilm formation on PHEs, which demonstrated reduced biofilm formation even during extended pasteurization runs up to 17h. By combining the above 2 approaches, it was possible to keep the sporeformers and spores counts low in milk and eventually in powders. Another approach that was found to be effective was to apply cavitation, combined with pasteurization, as an alternative processing step during the manufacturing of skim milk powder. Hydrodynamic cavitation was more effective, compared with ultrasonication, in reducing the counts of thermoduric sporeformers and their endospores. Pilot-scale trials successfully demonstrated that a 2 stage cavitation, when combined with pasteurization and followed through evaporation and spray drying, resulted in producing skim milk powder with reduced counts of sporeformers and spores. Further, combining optimized raw milk holding conditions based on regression models with that of hydrodynamic cavitation, as in line process step before pasteurization, was most effective in producing much lower spore count skim milk powder.

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