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Growth characteristics of post-pasteurization contaminants isolated from pasteurized milk

Published online by Cambridge University Press:  01 June 2009

R. Gregory Stevenson ,
G. Brian Wisdom ,
Michael T. Rowe  and
Deirdre A. McConaghy
R. Gregory Stevenson
Affiliation:
Department of Food Science and Food Microbiology, The Queen's University of Belfast, Newforge Lane, Belfast BT9 5PX, UK
G. Brian Wisdom
Affiliation:
Division of Biochemistry, School of Biology and Biochemistry, The Queen's University of Belfast BT9 7BL, UK
Michael T. Rowe
Affiliation:
Department of Food Science and Food Microbiology, The Queen's University of Belfast, Newforge Lane, Belfast BT9 5PX, UK Department of Agriculture for Northern Ireland, Newforge Lane, Belfast BT9 5PX, UK
Deirdre A. McConaghy
Affiliation:
Biometrics Division, Department of Agriculture for Northern Ireland, Newforge Lane, Belfast BT9 5PX, UK
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Summary

Nine organisms were isolated from separate pasteurized milk samples after they had been incubated at 6 °C for 5 d (European Union preincubated count, PIC), four from high count samples (> 5 x 106 cfu/ml) and five from low count samples (< 103 cfu/ml). When the organisms were harvested without overt stress being applied and subjected to a simulated PIC using UHT whole milk, all except one isolate gave comparatively high (> 106 cfu/ml) counts. The imposition of a heat stress at 50 °C prior to a simulated PIC resulted in a segregation of the isolates into those giving high and those giving low counts, which reflected the PIC values of the milk samples from which they were originally isolated. When the isolates were subjected to a cold stress (25 to 4 °C) and inoculated into nutrient broth at 4 °C, the high count isolates were found to have significantly (P < 0·05) shorter lag phases than the low count isolates.

Type
Original Articles
Information
Journal of Dairy Research , Volume 63 , Issue 4 , November 1996 , pp. 585 - 591
Copyright
Copyright © Proprietors of Journal of Dairy Research 1996

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References

REFERENCES

Baranyi, J., Roberts, T. A. & McClure, P. 1993 A non-autonomous differential equation to model bacterial growth. Food Microbiology 10 43–59CrossRefGoogle Scholar
Beuchat, L. R. 1991 Behaviour of Aeromonas spp. at refrigeration temperatures. International Journal of Food Microbiology 13 217–224CrossRefGoogle Scholar
Bratchell, N., McClure, P. J., Kelly, T. M. & Roberts, T. A. 1990 Predicting microbial growth: graphical methods for comparing models. International Journal of Food Microbiology 11 279–287CrossRefGoogle ScholarPubMed
British Standards Institution 1984 Microbiological examination for dairy purposes. Part 2. Methods of general application for enumeration of microorganisms. Section 2.3. Enumeration of microorganisms by surface plate technique for colony count. London: BSI (BS 4285.2.3)Google Scholar
Buchanan, R. L. & Klawitter, L. A. 1991 Effect of temperature history on the growth of Listeria monocytogenes Scott A at refrigeration temperatures. International Journal of Food Microbiology 12 235–245CrossRefGoogle Scholar
Buchanan, R. L. & Phillips, J. G. 1990 Response surface model for predicting the effects of temperature, pH, sodium chloride content, sodium nitrite concentration and atmosphere on the growth of Listeria monocytogenes. Journal of Food Protection 53 370–376, 381CrossRefGoogle ScholarPubMed
Chandler, R. E. & McMeekin, T. A. 1989 Temperature function integration as the basis of an accelerated method to predict the shelf life of pasteurized, homogenized milk. Food Microbiology 6 105–111CrossRefGoogle Scholar
Condón, S., García, M. L., Otero, A. & Sala, F. J. 1992 Effect of culture age, pre-incubation at low temperature and pH on the thermal resistance of Aeromonas hydrophila. Journal of Applied Bacteriology 72 322–326CrossRefGoogle ScholarPubMed
Cousin, M. A. 1982 Presence and activity of psychrotrophic microorganisms in milk and dairy products: a review. Journal of Food Protection 45 172–207CrossRefGoogle ScholarPubMed
Cowan, S. T. 1974 Cowan and Steel's Manual for the Identification of Medical Bacteria, 2nd edn. Cambridge: Cambridge University PressGoogle Scholar
Griffiths, M. W., Phillips, J. D. & Muir, D. D. 1984 Methods for rapid detection of post-pasteurization contamination in cream. Journal of the Society of Dairy Technology 37 22–26CrossRefGoogle Scholar
Janda, J. M. 1991 Recent advances in the study of the taxonomy, pathogenicity, and infectious syndromes associated with the genus Aeromonas. Clinical Microbiology Reviews 4 397–410CrossRefGoogle Scholar
Kirov, S. M., Hui, D. S. & Haywakd, L. J. 1993 Milk as a potential source of Aeromonas gastrointestinal infection. Journal of Food Protection 56 306–312CrossRefGoogle ScholarPubMed
Lanoeveld, L. P. M. & Cuperus, F. 1980 The relation between temperature and growth rate in pasteurized milk of different types of bacteria which are important to the deterioration of that milk. Netherlands Milk and Dairy Journal 34 106–125Google Scholar
Macaulay, D. M., Hawlrko, R. Z. & James, N. 1963 Effect of pasteurization on survival of certain psychrophilic bacteria. Applied Microbiology 11 90–92CrossRefGoogle ScholarPubMed
Rows, M. T. 1993 Predictive microbiology: uses for assessing quality and safety of dairy products. Journal of Industrial Microbiology 12 330–336Google Scholar
Schröder, M. J. A. 1984 Origins and levels of post pasteurization contamination of milk in the dairy and their effects on keeping quality. Journal of Dairy Research 51 59–67CrossRefGoogle ScholarPubMed
Schröder, M. J. A., Cousins, C. M. & McKinnon, C. H. 1982 Effect of psychrotrophic post-pasteurization contamination on the keeping quality at 11 and 5 °C of HTST-pasteurized milk in the UK. Journal of Dairy Research 49 619–630CrossRefGoogle ScholarPubMed
Shewan, J. M., Hobbs, G. & Hodokiss, W. 1960 A determinative scheme for the identification of certain genera of Gram-negative bacteria, with special reference to the Pseudomonadaceae. Journal of Applied Bacteriology 23 379–390CrossRefGoogle Scholar
Suhren, G. 1989 Producer microorganisms. In Enzymes of Psychrotrophs in Raiv Food, pp. 3–34 (Ed. McKellar, R. C.). Boca Raton, FL: CRC PressGoogle Scholar
Sutherland, A. D., Limond, A. M., MacDonald, F. & Hirst, D. 1993 Evaluation of the incubated plate count test for pasteurized milk. Journal of the Society of Dairy Technology 46 107–113CrossRefGoogle Scholar
Ternström, A., Lindbero, A. -M. & Molin, G. 1993 Classification of the spoilage flora of raw and pasteurized bovine milk, with special reference to Pseudomonas and Bacillus. Journal of Applied Bacteriology 75 25–34CrossRefGoogle ScholarPubMed
Wadstrom, T. & Ljungh, Å. 1991 Aeromonas and Plesiomonas as food- and water-borne pathogens. International Journal of Food Microbiology 12 303–311CrossRefGoogle Scholar
Weckbach, L. S. & Langlois, B. E. 1977 Effect of heat treatments on survival and growth of a psychrotroph and on nitrogen fractions in milk. Journal of Food Protection 40 857–862CrossRefGoogle ScholarPubMed
Wilson, A. B. & Gllmour, A. 1990 Numbers and types of psychrotrophic bacteria in pasteurized milk subjected to a preincubated plate count at 21 °C. Journal of the Society of Dairy Technology 43 79–81CrossRefGoogle Scholar