title: A flow cytometry method for rapid detection and enumeration of total bacteria in milk.
abstract: Application of flow cytometry (FCM) to microbial analysis of milk is hampered by the presence of milk proteins and lipid particles. Here we report on the development of a rapid (</=1-h) FCM assay based on enzymatic clearing of milk to determine total bacteria in milk. When bacteria were added to ultra-heat-treated milk, a good correlation (r >/= 0.98) between the FCM assay and the more conventional methods of plating and direct microscopic counting was achieved. Raw milk data showed a significant correlation (P < 0.01) and a good agreement (r = 0.91) between FCM and standard plate count methods. The detection limit of the FCM assay was </=10(4) bacteria ml of milk(-1). This limit is below the level of detection required to satisfy legislation in many countries and states.
authors.affiliation: Centre for Fluorimetric Applications in Biotechnology, Department of Biological Sciences, Macquarie University, Sydney, New South Wales 2109, Australia. tgunasek@rna.bio.mq.edu.au
authors.forename: T S
authors.initials: TS
authors.lastname: Gunasekera
authors.forename: P V
authors.initials: PV
authors.lastname: Attfield
authors.forename: D A
authors.initials: DA
authors.lastname: Veal
mesh_terms: D000818:Animals; D001419:Bacteria / Q000302:isolation & purification*; D015169:Colony Count, Microbial; D005434:Flow Cytometry / Q000379:methods*; D005516:Food Microbiology; D008892:Milk / Q000382:microbiology*