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Correlation of volatile compound concentrations with bacterial counts in whole pasteurised milk under various storage conditions
Author(s) -
Ziyaina Mohamed,
Rasco Barbara,
Coffey Todd,
Mattinson D Scott,
Sablani Shyam
Publication year - 2019
Publication title -
international journal of dairy technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.061
H-Index - 53
eISSN - 1471-0307
pISSN - 1364-727X
DOI - 10.1111/1471-0307.12557
Subject(s) - hexanal , chemistry , acetaldehyde , acetone , food science , volatile organic compound , chromatography , lipase , solid phase microextraction , gas chromatography , bacterial growth , ethanol , enzyme , gas chromatography–mass spectrometry , biochemistry , bacteria , organic chemistry , biology , mass spectrometry , genetics
This study investigated the relationship between bacterial counts and volatile organic compound ( VOC ) formation in 3.9% fat milk. The milk was stored at 7, 10, 13, 15 and 19 (±1 °C). Volatile compounds were measured using solid‐phase microextraction with gas chromatography. Enzyme activity was also monitored throughout the shelf life. Results show that volatile organic compound concentrations increased with higher bacterial counts (5.0–7.0 log 10 cfu/ mL ). Bacterial counts correlated closely with acetaldehyde, butanone, ethanol, hexanal, acetone and fatty acid concentrations. Results indicate that protease and lipase activities increased and correlated closely with VOC s. Formation of VOC s was detectable when protease and lipase activities reached 1.2–1.3 U/ mL and 0.32–0.350 meq/mL, respectively. These findings provide a basis for the monitoring of milk quality using chemical sensors that are sensitive to VOC s, particularly under conditions of thermal abuse.