Innovative use of oxygen reducing membrane fragments for the recovery of Campylobacter jejuni in laboratory media and food systems

Conventional methods for the recovery of Campylobacter from food require a cumbersome gassing procedure for liquid enrichment and microaerobic incubation of agar media for enumeration. In this study the efficiency of Hunt broth and Niroomand & Fung (NF) broth added with various supplements for recovery of Campylobacter was evaluated. Hunt broth containing 0.6 units/ml of Oxyrase® (commercial oxygen reducing membrane fragments) enhanced growth as effective as did the broth flushing by mixed gas and both broth showed better performance over NF broth. The addition of hemin, yeast extract, and blood stimulated C. jejuni growth. The effect of media volume on Campylobacter growth in Oxyrase® broth was studied by using three containers (13 x 100 mm tubes, 18 x 150 mm tubes, and 45 x 45 x 120 mm bottles). The ratio of head space volume to fluid medium volume of 1 to 3 yielded better performance for all strains tested. Campylobacter growth on solid agar containing Oxyrase® under aerobic atmosphere was studied using Oxydish™ and 18 x 150 mm tubes. At least 0.6 units/ml of Oxyrase® added were optimal for stimulating growth.; The efficiency of Hunt media containing Oxyrase® was compared with gassing method for detection of C. jejuni from inoculated ground beef. The efficiencies of Hunt medium using gassing and those with Oxyrase® added were similar. Broth containing 0.15 units/ml of Oxyrase® without blood effectively supported the growth of all strains. From inoculated chicken skin at 20 h of incubation, counts increased by 3.0 to 7.5 log CFU/ml for the gassing method and by 2.7–7.3 log CFU/ml for addition with 0.6 units/ml of Oxyrase® and blood. The efficiency of Oxyrase® broth and Oxyrase ® agar for isolation of Campylobacter from naturally contaminated chicken skin were studied. From one set of 50 samples tested, Oxyrase® broth with mCCDA recovered 96%, Bolton agar recovered 64% and Preston agar recovered 96% after 24 h-incubation for undiluted cultures. From another set of 50 samples, after Oxyrase®-enrichment, mCCDA detected 86%, Butzler detected 72%, Oxydish™ detected 76% and Oxyrase®-tubes detected 78%. This study indicated that appropriate Oxyrase® supplement allow the recovery of Campylobacter under aerobic environment during liquid enrichment and agar plating media for enumeration.