Inactivation of escherichia coli O157:H7 in cattle drinking water by sodium caprylate.
Escherichia coli O157:H7 is an important foodborne pathogen. Cattle serve as one of the major reservoirs of E. coli O157:H7, excreting the pathogen in feces. Environmental persistence of E. coli O157:H7 is critical in its epidemiology on farms, and the pathogen has been isolated from cattle water troughs. Thus, there is a need for an effective method for killing E. coli O157:H7 in cattle drinking water. In this study, the efficacy of sodium caprylate for killing E. coli O157:H7 in cattle drinking water was investigated. A four-strain mixture of E. coli O157:H7 was inoculated (6.0 log CFU/ml) into 100-ml samples of well water containing 0, 75, 100, or 120 mM sodium caprylate. Water samples containing 1% (wt/vol) bovine feces or feed also were included. The samples were incubated at 21 or 8 degrees C for 21 days. Water samples were analyzed for viable E. coli O157:H7 on days 0, 1, 3, 5, and 7 and weekly thereafter. Triplicate samples of each treatment and control were included, and the study was repeated twice. The magnitude of E. coli O157:H7 inactivation in water significantly increased (P < 0.01) with increases in caprylate concentration and storage temperature. At 120 mM, sodium caprylate completely inactivated E. coli O157:H7 in all the samples after 1 to 20 days, depending on the treatments. The presence of feces or feed also had a significant effect (P < 0.01) on the antibacterial property of caprylate; the presence of feces decreased the antibacterial effect, whereas addition of feed enhanced the effect. These results indicate that sodium caprylate is effective in killing E. coli O157:H7 in cattle drinking water, but detailed cattle palatability studies of water containing caprylate are necessary.
Amalaradjou
Mary Anne Roshni
MA
Department of Animal Science, Unit-4040, University of Connecticut, Storrs, Connecticut 06269, USA.
Annamalai
Thirunavukkarasu
T
Marek
Patrick
P
Rezamand
Pedram
P
Schreiber
David
D
Hoagland
Thomas
T
Venkitanarayanan
Kumar
K
D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D002210:Caprylates / Q000494:pharmacology*; D002417:Cattle; D015169:Colony Count, Microbial; D004197:Disease Reservoirs / Q000662:veterinary; D004305:Dose-Response Relationship, Drug; D004326:Drinking; D019453:Escherichia coli O157 / Q000187:drug effects* / Q000254:growth & development; D005243:Feces / Q000382:microbiology; D005618:Fresh Water / Q000382:microbiology; D013696:Temperature; D013997:Time Factors; D014871:Water Microbiology; D014881:Water Supply / Q000592:standards
D000900:Anti-Bacterial Agents; D002210:Caprylates; C031492:octanoic acid