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Comparison of rapid tests for assessing UHT milk sterility

Published online by Cambridge University Press:  01 June 2009

Jorge A. Reinheimer  and
Maria R. Demkow
Jorge A. Reinheimer
Affiliation:
Instituto de Lactología Industrial, Facultad de Ingeniería Química, Santiago del Estero 2829, 3000 Santa Fe, Argentina
Maria R. Demkow
Affiliation:
Instituto de Lactología Industrial, Facultad de Ingeniería Química, Santiago del Estero 2829, 3000 Santa Fe, Argentina
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Summary

Samples of UHT milk were contaminated at two levels (102 and 104 cfu/ml) with 52 bacterial strains associated with spoilage. Samples were assayed, using various tests, to determine efficiency in detecting non-sterility after an incubation period shorter than that advised in standard procedures. The tests performed were colony count, titratable acidity and pH modification, organoleptic assessment, stability towards ethanol (68, 80 and 88% v/v), resazurin and nitrate reduction. After 3 d incubation at 30 °C every case was detected by the resazurin test with a good statistical probability (P = 0·999). Reliability was not so high in all other tests, even after 14 d incubation.

Type
Original Articles
Information
Journal of Dairy Research , Volume 57 , Issue 2 , May 1990 , pp. 239 - 243
Copyright
Copyright © Proprietors of Journal of Dairy Research 1990

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References

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