Antibacterial effect of monocaprylin on Escherichia coli O157:H7 in apple juice.
The antibacterial effect of low concentrations of monocaprylin on Escherichia coli O157:H7 in apple juice was investigated. Apple juice alone (control) or containing 2.5 mM (0.055%) or 5 mM monocaprylin was inoculated with a five-strain mixture of E. coli O157:H7 at approximately 6.0 log CFU/ml. The juice samples were stored at 23 or 4 degrees C for 14 or 21 days, respectively, and the population of E. coli O157:H7 was determined on tryptic soy agar plates supplemented with 0.6% yeast extract. At both storage temperatures, the population of E. coli O157:H7 in monocaprylin-supplemented juice samples was significantly lower (P < 0.05) than that in the control samples. The concentration of monocaprylin and the storage temperature had a significant effect on the inactivation of E. coli O157:H7 in apple juice. Monocaprylin at 5 mM was significantly more effective than 2.5 mM monocaprylin for killing E. coli O157:H7 in apple juice. Inactivation of E. coli O157:H7 by monocaprylin was more pronounced in juice stored at 23 degrees C than in the refrigerated samples. Results of this study indicated that monocaprylin is effective for killing E. coli O157:H7 in apple juice, but detailed sensory studies are needed to determine the organoleptic properties of apple juice containing monocaprylin.
Nair
Manoj Kumar Mohan
MK
Department of Animal Science, Unit 40, University of Connecticut, 3636 Horsebarn Hill Road Extension, Storrs, Connecticut 06269, USA.
Abouelezz
Hanem
H
Hoagland
Thomas
T
Venkitanarayanan
Kumar
K
D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001628:Beverages / Q000382:microbiology* / Q000592:standards; D002210:Caprylates / Q000494:pharmacology*; D015169:Colony Count, Microbial; D004305:Dose-Response Relationship, Drug; D019453:Escherichia coli O157 / Q000187:drug effects* / Q000254:growth & development; D005516:Food Microbiology; D005519:Food Preservation / Q000379:methods*; D027845:Malus; D013649:Taste; D013696:Temperature; D013997:Time Factors
D000900:Anti-Bacterial Agents; D002210:Caprylates; C031492:octanoic acid