Hostname: page-component-745bb68f8f-d8cs5 Total loading time: 0 Render date: 2025-02-02T03:51:45.042Z Has data issue: false hasContentIssue false
  • English
  • Français

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.
Get access Rights & Permissions [Opens in a new window]

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

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

Aschaffenburg, R. & Drewry, J. 1959 New procedure for the routine determination of the varions non-casein proteins of milk. 15th International Dairy Congress, London 3 16311637Google Scholar
Buchholz-Berchtold, S. 1977 [The Determination of Endotoxins from Gram-negative Bacteria in Milk with the Limulus Test.] Dissertation, Ludwig-Maximilian Universität. MünchenGoogle Scholar
Friberger, P., Knos, M. & Mellstam, L. 1982 A quantitative endotoxin assay utilizing LAL and a chromogenic substrate. In Endotoxins and their detection with the Limulus amoebocyte lysate test (Progress in Clinical and Biological Research 93), pp. 195–206 (Ed. Novitsky, T. J.). New York: A. R. LissGoogle Scholar
Hahn-Hägerdal, B. & Svensson, A. 1986 A chromogenic substrate Limulus assay applied to raw milk. In Milk; the Vital Force (Posters, International Dairy Congress 22), p. 132 (Ed. International Dairy Fedwration). Dordrecht: D. ReidelGoogle Scholar
Iwanaga, S., Morita, T., Harada, T., Nakamura, S., Niwa, M., Takada, K., Kimura, T. & Sakakibara, S. 1978 Chromogenic substrates for horseshoe crab clotting enzyme. Its application for the assay of fractional endotoxins. Haemostasis 7 183–186Google Scholar
Khuri, A. I. & Cornell, J. A. 1987 Second order models and designs. In Response Surfaces, Designs d Analyses, pp. 105–148 (Eds Khuri, A. and Cornell, J.). New York: DekkerGoogle Scholar
Levin, J. & Bang, F. B. 1964 A description of cellular coagulation in the Limulus. Bulletin of Johns Hopkins Hospital 115 337–345Google Scholar
Mossel, D. A. A. & Tamminga, S. K. 1980 [Counting and grouping of Gram-negative rodlike bacteria.] In [Methods for the Microbiological Analysis of Foodstuffs], 2nd edn, pp. 49–54 (Eds Mossel, D. A. A. and Tamminga, S. K.). Zeist: P. G. NoordervlietGoogle Scholar
Mottar, J. 1981 Heat resistant enzymes in UHT milk and their influence on sensoric changes during uncooled storage. Milchwissenschaft 36 87–91Google Scholar
Mottar, J. 1983 [Characterization and Properties of Ultra-High Heated Milk.] Thesis, State Univ. of GhentGoogle Scholar
Mottar, J. 1987 A colorimetric endotoxin assay for the determination of the bacteriological quality of milk. Netherlands Milk and Dairy Journal 41 137–145Google Scholar
Mottar, J. 1988 The determination of endotoxins as a measure for the bacteriological quality of foodstuffs. Belgian Journal of Food Chemistry and Biotechnology 43 69–74Google Scholar
Oishi, H., Takaoka, A., Hatayama, Y., Matsuo, T. & Sakata, Y. 1985 Automated Limulus Amoebocyte Lysate (LAL) test for endotoxin analysis using a new Toxinometer ET-201. Journal of Parenteral Science and Technology 39 194–199Google Scholar
Suhren, G., Heeschen, W. & Südi, J. 1986 Evaluation of the lipopolysaccharide (LPS) content as determined by the limulus test in milk and milk products. I. Investigations with pure cultures. Milchwissenschaft 41 74–79Google Scholar
Young, N. S., Levin, J. & Prendergast, R. A. 1972 An invertebrate coagulation System activated by endotoxin: evidence for enzymatic mediation. Journal of Clinical Investigation 51 17901797Google Scholar