Reduction of Listeria monocytogenes in raw catfish fillets by essential oils and phenolic constituent carvacrol.
The antimicrobial activity of various essential oils and carvacrol was determined on fresh raw catfish fillets against a 4-strain Listeria monocytogenes mixture representing serotypes 1/2b, 3b, 4b, and 4c that were predominantly isolated from catfish processing environments. Thyme oil, oregano oil and carvacrol exhibited concentration and time dependent responses in broth against L. monocytogenes; for example 0.5% concentrations resulted in 4 log CFU/mL reduction within 30 min whereas 0.1% concentrations required more than 24 h for the same level of reduction. Lemon, orange, and tangerine oils, at 0.5% showed listeriostatic effect in which 4 log CFU/mL of the initial L. monocytogenes load was unchanged at 4 °C in 10 d whereas 1% concentrations were listericidal in a time dependent manner. Apart from carvacrol, efficacy of tested essential oils in reducing L. monocytogenes and total microbial load from catfish fillet was very limited. Dipping treatment of catfish fillets in 2% carvacrol solution for 30 min at 4 °C reduced L. monocytogenes to an undetectable level from their initial load of 5 log CFU/g and reduced total microbial load from catfish fillets by approximately 5 log CFU/g. In sensory analysis trained panelist preferred control samples over 2% carvacrol treated samples implying potential limitation in applicability of carvacrol for fillet treatments.
Dept of Food Science, Nutrition and Health Promotion, Mississippi State Univ, Mississippi State, MS 39762, USA.
Monil A
MA
Desai
Kamlesh A
KA
Soni
Ramakrishna
R
Nannapaneni
M Wes
MW
Schilling
Juan L
JL
Silva
D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D058491:Bacterial Load; D002397:Catfishes; D000081007:Cymenes; D005506:Food Contamination / Q000032:analysis; D005511:Food Handling; D005516:Food Microbiology; D005519:Food Preservation / Q000379:methods*; D008089:Listeria monocytogenes / Q000187:drug effects / Q000302:isolation & purification*; D039821:Monoterpenes / Q000494:pharmacology*; D009822:Oils, Volatile / Q000494:pharmacology*; D010636:Phenols / Q000494:pharmacology; D017747:Seafood
D000900:Anti-Bacterial Agents; D000081007:Cymenes; D039821:Monoterpenes; D009822:Oils, Volatile; D010636:Phenols; C073316:carvacrol