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Routine Limulus amoebocyte lysate (LAL) test for endotoxin determination in milk using a Toxinometer ET-201

Published online by Cambridge University Press:  01 June 2009

Jozef Mottar ,
Jan De Block ,
Martine Merchiers ,
Kristien Vantomme  and
Renaat Moermans
Jozef Mottar
Affiliation:
Government Dairy Research Station, B-9090 Ghent, Belgium
Jan De Block*
Affiliation:
Government Dairy Research Station, B-9090 Ghent, Belgium
Martine Merchiers
Affiliation:
Government Dairy Research Station, B-9090 Ghent, Belgium
Kristien Vantomme
Affiliation:
Government Dairy Research Station, B-9090 Ghent, Belgium
Renaat Moermans
Affiliation:
Biometrie Unit, Agricultural Research Centre, B-9090 Ghent, Belgium
*
† For correspondence.
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Summary

A rapid method of performing the Limulus amoebocyte lysate (LAL) test in milk is proposed using the Toxinometer ET-201. This instrument measured the increase in turbidity due to the interaction between the endotoxins of the Gram-negative bacteria and the LAL reagent, monitored the ratio Rt of the sequential to the initial transmission at 12 s intervais and quantified endotoxins by determination of the reaction time Tr required to obtain a 5% decrease in Rt. There was a good correlation between the toxinometrically determined endotoxin concentrations and the number of Gram-negative bacteria (SD, 0·18 log(plate count units)), and the repeatability (CV, 6·10%) was high. The assay may be useful for screening raw materials for UHT milk production, as the endotoxin content of the raw material is related to the rest proteinase activity in the UHT milk.

Type
Original Articles
Information
Journal of Dairy Research , Volume 60 , Issue 2 , May 1993 , pp. 223 - 228
Copyright
Copyright © Proprietors of Journal of Dairy Research 1993

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References

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