Inactivation of Escherichia coli O157:H7 on the intact and damaged portions of lettuce and spinach leaves by using allyl isothiocyanate, carvacrol, and cinnamaldehyde in vapor phase.
Antimicrobials in the vapor phase might be more effective in inactivating Escherichia coli O157:H7 cells attached to leafy greens than aqueous antimicrobials. We determined the activity of allyl isothiocyanate (AIT), cinnamaldehyde, and carvacrol against E. coli O157:H7 on intact and damaged lettuce and spinach tissue. Samples were treated with various concentrations of antimicrobial in the vapor phase at 0, 4, and 10 degrees C in an enclosed container. On intact lettuce surface, the vapor of the lowest concentration of these antimicrobials inactivated >4 log of E. coli O157:H7 at 0 and 4 degrees C in 4 days and at 10 degrees C in 2 days. However, at the tissue damaged by cutting, the highest concentration reduced the population by 4 log at 0 degrees C and 2 to 4 log at 4 degrees C in 4 days. These concentrations also reduced the population of the pathogen by 1 to 3 log at 10 degrees C in 2 days. The pathogen population on spinach surface was reduced by 1 log less than on lettuce surface. However, reduction of the pathogen within spinach tissue was 2 and 3 log less than within lettuce tissue at 0 and 4 degrees C, respectively. Overall, greater inactivation occurred on lettuce than spinach leaves and on the leaf surfaces than at the damaged area. Using antimicrobials in the vapor phase may improve the safety of refrigerated leafy greens marketed in sealed packages.
Obaidat
Mohammad M
MM
Department of Food Science and Technology, University of Georgia, Athens, Georgia 30602-7610, USA.
Frank
Joseph F
JF
D000171:Acrolein / Q000031:analogs & derivatives / Q000494:pharmacology; D015169:Colony Count, Microbial; D003257:Consumer Product Safety; D000081007:Cymenes; D004305:Dose-Response Relationship, Drug; D019453:Escherichia coli O157 / Q000187:drug effects* / Q000254:growth & development; D005506:Food Contamination / Q000032:analysis; D005511:Food Handling / Q000379:methods; D005516:Food Microbiology; D005519:Food Preservation / Q000379:methods*; D005520:Food Preservatives / Q000494:pharmacology*; D006801:Humans; D017879:Isothiocyanates / Q000494:pharmacology; D018545:Lactuca / Q000382:microbiology*; D039821:Monoterpenes / Q000494:pharmacology; D018724:Spinacia oleracea / Q000382:microbiology*; D013696:Temperature; D014835:Volatilization
D000081007:Cymenes; D005520:Food Preservatives; D017879:Isothiocyanates; D039821:Monoterpenes; D000171:Acrolein; C073316:carvacrol; C004471:allyl isothiocyanate; C012843:cinnamaldehyde