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Effects of fat, casein and lactose on high-pressure destruction of Escherichia coli K12 (ATCC-29055) in milk

Paper ID Volume ID Publish Year Pages File Format Full-Text
19270 43056 2009 6 PDF Available
Title
Effects of fat, casein and lactose on high-pressure destruction of Escherichia coli K12 (ATCC-29055) in milk
Abstract

High-pressure (HP) destruction of Escherichia coli K12 suspended in commercial pasteurized milk (0, 3.25 and 5% fat), peptone water (0.1%), and phosphate buffer (0.2 mol/l Na2HPO4 and 0.2 mol/l NaH2PO4) supplemented with different amounts of casein or lactose (1–4%) was investigated. HP treatment resulted in the highest level of E. coli destruction in the buffer (possibly because it contained no nutrients), followed by those in peptone water and least in milk. Therefore, milk and peptone provided some baro-protection to the destruction of E. coli during the HP treatment. Fat content in milk between 0, 3.25 and 5% had no significant (P > 0.05) influence on the HP destruction of E. coli. The supplement of either casein or lactose to milk did not influence the level of HP destruction of E. coli. However, the baro-protection became significant during HP treatment when casein or lactose was added the buffer. The buffer solution supplemented with 1–4% casein showed a baro-protective effect equivalent to that in milk. Lactose supplement to buffer also caused baro-protection, though the effect was relatively less pronounced. However, no significant difference in the baro-protection effect was observed among the buffer samples supplemented with different levels (1, 2 and 4%) of lactose or casein. Therefore the major contributors for baro-protection of E. coli in milk during HP treatment appear to be casein and lactose, rather than the fat content.

Keywords
High pressure; Destruction kinetics; E. coli; Food safety; Milk
First Page Preview
Effects of fat, casein and lactose on high-pressure destruction of Escherichia coli K12 (ATCC-29055) in milk
Publisher
Database: Elsevier - ScienceDirect
Journal: Food and Bioproducts Processing - Volume 87, Issue 1, March 2009, Pages 1–6
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering