Microbiological Instrumentation for the Food Industry: A Review

This report describes the detection of Staphylococcus aureus in buffer and in several kinds of food by flow cytometry. Fluorescein isothiocyanate conjugated anti‐protein A antibodies were used in a 4‐h procedure to label cells, 105‐106 cells/mL are needed. the use of single parameter, green fluorescence, enabled specific differentiation of S. aureus from other bacteria including 11 Staphylococcus species. the flow cytometric method can detect S. aureus in food samples after 48‐h enrichment in trypticase soy broth with 10% NaCl. As low as 2 S. aureus cells present in 10 mL enrichment broth could grow to a population density detectable by the flow cytometric method after enrichment. This method was faster and less laborious than the conventional BAM (Bacteriological Analytical Manual) or AOAC (Association of Official Analytical Chemists) methods, and could be automated for analysis of S. aureus in food.

Section: Introductionmentioning

confidence: 99%

RAPID DETECTION of STAPHYLOCOCCUS AUREUS IN FOOD BY FLOW CYTOMETRY

Chang

Ding

1992

“…This instrumentation also has been used to speciate microorganisms according to their light scatter, fluorescence, antigen-antibody reactions and enzymatic activities (Steinkamp 1984; Barnett et ul. 1984;Goldschmidt 1985Goldschmidt , 1991Chang and Ding 1992).…”

Section: Introductionmentioning

confidence: 99%

THE USE of FLOW CYTOMETRY FOR RAPID IDENTIFICATION of SALMONELLAE

Goldschmidt

1992

Flow cell cytometry can be used in a sensitive fluorescent immunoassay to rapidly identify salmonellae of Groups D and E. Staphylococcal Protein A couples with the Fc region of many antibodies, especially immunoglobulin G. When afluorescent marker, fluorescein isothiocyanate, is conjugated to Protein A , an antibodyantigen reaction can be visualized in a flow cell cytometer with an appropriate optical sensor afrer excitation. Ten thousand cells were individually analyzed in each cytometer run within a minute. The resultant data, presented as histograms and tables, indicated the number of cells in the suspension reacting positively with the antiserum by $uorescence, cell size, distribution and light scatter. This provides an in-depth analysis of the antibody-antigen reaction not possible with other types of immunoassays. lCorrespondence should be sent to: Dr. Millicent Goldschrnidt, Dental Branch, The University of

“…Flow cell cytometry has been used to detect and characterize microorganisms using metabolite synthesis, antigen-antibody , and even DNA/RNA (Barnett et al 1984;Pinder et al 1980;Goldschmidt 1981Goldschmidt , 1985Goldschmidt , 1991Goldschmidt , 1993. The instrument was initially adapted from particle counters and automated differential blood counting machines (Valinsky 1992).…”

Section: Introductionmentioning

confidence: 99%

“…The use of fluorescent markers, some attached to antibodies, has been used to rapidly identify microorganisms (Steinkamp 1984;Monsigny ef af. 1989;Boye and Ldbner-Olesen 1990;Goldschmidt 1985Goldschmidt , 1991Goldschmidt and 1993Phillips ef af. 1987: Miller andQuarles 1990).…”

Section: Introductionmentioning

confidence: 99%

THE USE of FLOW CYTOMETRY FOR the RAPID CHARACTERIZATION of MONOCLONAL ANTIBODY PRODUCTION

Goldschmidt

1992

Flow cell cytometry is reported here as a rapid fluorescent immunoassay method to characterize monoclonal antibody production in hybridoma cultures. Actinomyces viscosus was the bacterium chosen as a model to illustrate this procedure. Fluorescein isothiocyanate (FITC), coupled to staphylococcal Protein A (PA), was used as the fluorescent marker to detect and quantitate antigen‐antibody reactions. Flow cell cytometry was also used with rabbit polyclonal antibodies to A. viscosus coupled with PAFITC for comparison and verification of the two procedures. Over 25,000 individual bacteria could be analyzed in a single cytometer injection within 2 min. the data, presented as histograms and figures, supported the feasibility of this method and also provided an in‐depth analysis of the degree of fluorescence, cell size, distribution and light scatter not available with most other immunoassay methods.