Methods for rapid separation and concentration of bacteria in food that bypass time-consuming cultural enrichment

The rapid detection of pathogenic organisms that cause foodborne illnesses is needed to insure food safety. Conventional methods for the detection of pathogens in foods are time-consuming and labor-intensive. New advanced rapid methods (i.e., polymerase chain reaction, DNA probes) are more sensitive and selective than conventional techniques, but many of these tests are inhibited by food components, rendering them dependent on slow cultural enrichment. The need for alternative methods that will rapidly separate and concentrate bacteria directly from food samples, thereby reducing the time required for these new rapid detection techniques, is evident. Separation and concentration methods extract target bacteria from interfering food components and/or concentrate bacteria to detectable levels. This review describes several methods used to separate and/ or concentrate bacteria in food samples. Several methods discussed here, including centrifugation and immunomagnetic separation, have been successfully used, individually and in combination, to rapidly separate and/or concentrate bacteria from food samples in less time than is required for cultural enrichment.