HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Peterson, R. D. Articles by Keyser, W. L. Search for Related Content PubMed Articles by Peterson, R. D. Articles by Keyser, W. L.

Effect of Homogenization and Heat Treatment on the Leucocyte Count of Milk

Department of Dairy and Food Science, Cornell University, Ithaca, New York

ABSTRACT

The leucocyte count has been used for many years as an indirect method for detecting mastitis; however, it is seldom applied to pasteurized milks; the reason being that the leucocyte cells are believed to be broken up in the pasteurization and homogenization processes, and a cell count would be too low if whole cells were counted or too high if fragments and whole cells were counted.

While correlating the leucocyte count with the modified Whiteside Test it was found that leucocytes heat-treated prior to centrifugation became more resistant to breaking up. Unheated cells in milk start to breakup at 4,000 g for 5 min, whereas cells rapidly heated to 82 C and immediately cooled will withstand 30,000 g for 5 min. The walls of unheated cells subjected to 30,000 g for 5 min are practically all ruptured.

Using this as a basis, a study was undertaken to determine the extent of leucocyte breakup due to the various heat and homogenization treatments in a HTST-UHT¹ pasteurization system.