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ARS Home » Plains Area » College Station, Texas » Southern Plains Agricultural Research Center » Food and Feed Safety Research » Research » Publications at this Location » Publication #99974

Title: BACTERIOCIDAL EFFECT OF SODIUM CHLORATE ON ESCHERICHIA COLI O157:H7 AND SALMONELLA TYPHIMURIUM DT104 IN RUMEN CONTENTS

Author
item Anderson, Robin
item Nisbet, David
item Buckley, Sandra - Sandy
item Harvey, Roger
item Stanker, Larry

Submitted to: American Society of Animal Science Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 3/14/1999
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Escherichia coli O157:H7 (EC) and Salmonella typhimurium DT104 (ST) are important food borne pathogens affecting the beef industry, and strategies are sought to rid these from slaughter cattle. As members of the family Enterobacteriaceae, both pathogens possess respiratory nitrate reductase. Since most ruminal anaerobes lack nitrate reductase, and since most known respiratory nitrate reductases also reduce chlorate to cytotoxic chlorite, we hypothesized that chlorate may selectively inhibit EC and ST. To test this, ruminal fluid, collected from a cannulated cow maintained on pasture (predominantly rye grass), was mixed 1:1 with phosphate buffer (pH 6.8) containing cellobiose, glucose, soluble starch, and xylose (1% wt/vol each). The buffered ruminal fluid was incubated anaerobically (39C) with or without 5 mM sodium chlorate and either 7.3 x 10**5 colony forming units/ml (cfu/ml) of a novobiocin (NO) and nalidixic acid (NA) resistant EC or 2.5 x 10**5 cfu/ml of ST. Colony counts for EC were determined via direct plating on MacConkey agar containing 25 ug NO/ml and 20 ug NA/ml and for ST via plating on Brilliant Green agar containing NO and chloramphenicol (25 ug/ml each). Concentrations of EC declined slightly to 1.3 x 10**5 cfu/ml following 24 hr culture in ruminal fluid without added chlorate but declined rapidly (to