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

Published online by Cambridge University Press:  01 June 2009

Anthony R. Bucky
Affiliation:
Department of Microbiology, University of Leeds, Leeds LS2 9JT, UK
Patrick R. Hayes
Affiliation:
Department of Microbiology, University of Leeds, Leeds LS2 9JT, UK
David S. Robinson
Affiliation:
Procter Department of Food Science, University of Leeds, Leeds LS2 9JT, UK

Summary

Cultures of Pseudomonas P46 grown in whole milk to contain ∼ 2 × 107 or 1 × 108 viable cells ml−1 before ultra high temperature (UHT) treatment (140°C for 5 s) demonstrated near linear increases in the concentration of short-chain free fatty acids (FFA) during storage at 20°C. However with 5 × 106 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°C for 5 s followed by 60°C for 5 min) reduced the rate of production of volatile FFA to < 10% of the rates achieved after the normal UHT treatment.

Type
Original Articles
Copyright
Copyright © Proprietors of Journal of Dairy Research 1987

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References

REFERENCES

Andersson, R. E., Hedlund, C. B. & Jonsson, U. 1979 Thermal inactivation of a heat-resistant lipase produced by the psychrotrophic bacterium Pseudomonas fluorescens. Journal of Dairy Science 62 361367Google Scholar
Bucky, A. R., Robinson, D. S. & Hayes, P. R. 1986 Method of deactivating heat-stable enzymes. British Patent Application No. 8606524Google Scholar
Bucky, A. R., Robinson, D. S. & Hayes, P. R. 1987 Enhanced deactivation of bacterial lipases by a modified UHT treatment. Journal of Food Technology. In press.CrossRefGoogle Scholar
Cowan, S. T. (REV.) 1974 Cowan & Steel's Manual for the Identification of Medical Bacteria 2nd ednCambridge: University PressGoogle Scholar
Dring, R. & Fox, P. F. 1983 Purification and characterization of a heat-stable lipase from Pseudomonas fluoresceins AFT 29. Irish Journal of Food Science and Technology 7 157171Google Scholar
Fox, P. F. & Stepaniak, L. 1983 Isolation and some properties of extracellular heat-stable lipases from Pseudomonas fluorescens strain AFT 36. Journal of Dairy Research 50 7789CrossRefGoogle ScholarPubMed
Griffiths, M. W., Phillips, J. D. & Muir, D. D. 1981 Thermostability of proteases and lipases from a number of species of psychrotrophic bacteria of dairy origin. Journal of Applied Bacteriology 50 289303CrossRefGoogle ScholarPubMed
Law, B. A., Sharpe, M. E. & Chapman, H. R. 1976 The effect of lipolytic Gram-negative psychrotrophs in stored milk on the development of rancidity in Cheddar cheese. Journal of Dairy Research 43 459468CrossRefGoogle Scholar
Needs, E. C., Ford, G. D., Owen, A. J., Tuckley, B. & Anderson, M. 1983 A method for the quantitative determination of individual free fatty acids in milk by ion exchange resin adsorption and gas-liquid chromatography. Journal of Dairy Research 50 321329Google Scholar
Pettipher, G. L., Mansell, R., McKinnon, C. H. & Cousins, C. M. 1980 Rapid membrane filtration- epifluorescent microscopy technique for direct enumeration of bacteria in raw milk. Applied and Environmental Microbiology 39 423429CrossRefGoogle ScholarPubMed
Scanlan, R. A., Sather, L. A. & Day, E. A. 1965 Contribution of free fatty acids to the flavor of rancid milk. Journal of Dairy Science 48 15821584CrossRefGoogle Scholar
West, F. B., Adams, D. M. & Speck, M. L. 1978 Inactivation of heat resistant proteases in normal ultra-high temperature sterilized skim milk by a low temperature treatment. Journal of Dairy Science 61 10781084Google Scholar