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 HighWire Citing Articles via Google Scholar Google Scholar Articles by Pratt-Lowe, E. L. Articles by Barrett, E. L. Search for Related Content PubMed Articles by Pratt-Lowe, E. L. Articles by Barrett, E. L.

Heat Resistance of Alkaline Phosphatases Produced by Microorganisms Isolated from California Mexican-Style Cheeses

Department of Food Science and Technology, University of California, Davis 95616

ABSTRACT

Samples of Queso Fresco produced in California were tested for microbiological quality and alkaline phosphatase activity. Total plate counts ranged from 6 to 8 logs for freshly purchased cheeses. The majority of bacteria were nonlactic psychrotrophs. Coliform and enteric counts were greater than or equal to six logs in all samples. Colonies isolated on Standard Methods Agar were inoculated into a variety of media and incubated at 20°C. Each culture was tested for alkaline phosphatase activity by the Scharer test. The resistance of each phosphatase-positive culture to a heat treatment of 63°C for 30 min was also determined. The degree of enzyme inactivation varied between cultures when different growth media were used. Alkaline phosphatases sensitive to pasteurization were produced by several isolates under culture conditions. The Scharer test may not be a reliable indicator of pasteurization in Queso Fresco cheeses.

This article has been cited by other articles:

				P. Waldmann, J. Hallander, F. Hoti, and M. J. Sillanpaa Efficient Markov Chain Monte Carlo Implementation of Bayesian Analysis of Additive and Dominance Genetic Variances in Noninbred Pedigrees Genetics, June 1, 2008; 179(2): 1101 - 1112. [Abstract] [Full Text] [PDF]