Inactivation of Listeria monocytogenes on frankfurters by monocaprylin alone or in combination with acetic acid.
The antilisterial activity of monocaprylin (MC) and its combination with acetic acid (AA) on frankfurters was investigated. Each frankfurter was surface inoculated with a three-strain mixture of Listeria monocytogenes to obtain an inoculation level of 4.0 log CFU per frankfurter, and then dipped for 35 s in sterile deionized water (45 or 50 degrees C) containing 1% ethanol (control), 50 mM MC plus 1% ethanol, 1% AA plus 1% ethanol, or 50 mM MC plus 1% AA plus 1% ethanol. Samples were vacuum packaged, stored at 4 degrees C for 77 days, and analyzed for L. monocytogenes. Sensory odor and color of frankfurters were evaluated using a 9-point hedonic scale. Color was also objectively measured using the Minolta Chroma Meter. From day 0 to day 77, population counts of L. monocytogenes on frankfurters dipped in antimicrobial solutions at 50 degrees C were consistently lower than the control counts. Similar results were observed for samples treated at 45 degrees C. However, L. monocytogenes grew readily on control samples at both temperatures. Dipping of frankfurters in antimicrobial solutions (45 or 50 degrees C) significantly reduced (P < 0.05) the populations of L. monocytogenes. After 70 days of storage, L. monocytogenes was completely killed in samples dipped in MC+AA solution at 50 degrees C. The antimicrobial treatments did not affect the odor or color of the samples (P > 0.05). Overall, results indicated that dipping of frankfurters with MC reduced L. monocytogenes, and inclusion of AA further enhanced MC antilisterial activity, without any negative effect on odor or color.
Department of Animal Science, Unit-4040, University of Connecticut, Storrs, Connecticut 06269, USA.
Marilyn
M
Garcia
Mary Anne Roshni
MA
Amalaradjou
Manoj Kumar Mohan
MK
Nair
Thirunavukkarasu
T
Annamalai
Suman
S
Surendranath
Seok
S
Lee
Thomas
T
Hoagland
David
D
Dzurec
Cameron
C
Faustman
Kumar
K
Venkitanarayanan
D019342:Acetic Acid / Q000494:pharmacology*; D002210:Caprylates / Q000494:pharmacology*; D015169:Colony Count, Microbial; D003257:Consumer Product Safety; D004305:Dose-Response Relationship, Drug; D004357:Drug Synergism; D005519:Food Preservation / Q000379:methods*; D005520:Food Preservatives / Q000494:pharmacology*; D005989:Glycerides / Q000494:pharmacology*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008089:Listeria monocytogenes / Q000187:drug effects* / Q000254:growth & development; D008461:Meat Products / Q000382:microbiology*; D009812:Odorants / Q000032:analysis; D010858:Pigmentation; D013696:Temperature; D013997:Time Factors
D002210:Caprylates; D005520:Food Preservatives; D005989:Glycerides; D019342:Acetic Acid; C025343:monooctanoin