A filter called ACG/B (activated carbon particles in a matrix of cellulose and glass fibers, H. R. Reeve-Angel, Clifton, N.J.) was tested with and without Cat-Floc for recovery of CB1, EC6, and PO1 from a variety of foods (Kostenbader and Cliver 1973) . Meat products included ground beef and frankfurter sausages; chicken salad served as a representative mixed meat product; fresh vegetables included lettuce and carrots; flour products were creamfilled cakes and bread rolls; seafoods comprised oysters (Crassostrea virginica) and clams (Mercenaria mercenaria); dairy products included creamed-curd cottage cheese and cheddar cheese. Filtrates could be filter-sterilized (0.20 lm porosity) and concentrated before testing in cell culture; recoveries of at least 80% were recorded with optimal selection of procedures. In a later version, the Whatman GF/F glass fiber filter was substituted and a great number (seven dry-form and 13 liquid) of polyelectrolytes were compared for recovery of PO1 from ground beef (Kostenbader and Cliver 1981) . Cat-Floc T performed best among the liquids (88% recovery), and Cation 105C (ICI America, Wilmington, Del.) was the best of the dry-form flocculants (107% recovery). Cat-Floc was also found useful in the recovery of reovirus 1 from ground beef (C73% recovery) and oysters (C. virginica, C50% recovery). Reviews comparing the various extraction and detection methods as applied to different foods were published in the Journal of Food Protection (Cliver et al. 1983a, b) and in various editions of the Compendium of Methods for the Microbiological Examination of Foods (Cliver 1976; Cliver et al. , 1992 Richards and Cliver 2001) .