Abstract # A-51

A Blood-Free Enrichment Medium for Growth of Campylobacter Spp. Under Normal Atmospheric Conditions. T.T. Tran, U.S. Food and Drug Administration, Washington, DC 20204

Recovery limits of Campylobacter jejuni strains JH93 and ATCC 29428 from a new blood-free enrichment broth (BFEB) were investigated under normal oxygen tensions. Six replicates of C. Jejuni were inoculated at each of five concentration levels (10-2 - 102 cfu/ml) into 50 ml BFEB containing 10% food homogenate in 50 ml polypropylene screw cap conical tubes. After 24 h enrichment under normal oxygen tensions, C. Jejuni were isolated on four selective agars. There were no significant differences (p > 0.05) among the four selective agars used. The pooled adjusted (least squares) mean recovery limit 50% endpoint values (RL50) for the two bacterial strains were calculated to be 0.4 (plain BFEB), 0.9 (crabmeat), 1.7 (mushroom), 1.7 (raw milk), and 2.1 (oyster) cfu/5 g food. Significant differences (p < 0.05) were found between RL50 values for plain BFEB and the four foods, and between crabmeat and the other three food types. Significant differences (p < 0.05) were also found between bacterial strains within each food type. Although the recovery rate for the BFEB was slightly lower than the existing FDA-BAM method, the BFEB method did not require the use of blood, special equipment, or oxyrase to reduce oxygen tensions.