Carvacrol and cinnamaldehyde inactivate antibiotic-resistant Salmonella enterica in buffer and on celery and oysters.
The emergence of antibiotic-resistant Salmonella is of concern to food processors. The objective of this research was to identify antimicrobial activities of cinnamaldehyde and carvacrol against antibiotic-resistant Salmonella enterica in phosphate-buffered saline (PBS) and on celery and oysters. Twenty-three isolates were screened for resistance to seven antibiotics. Two resistant and two susceptible strains were chosen for the study. S. enterica cultures (10(5) CFU/ml) were added to different concentrations of cinnamaldehyde and carvacrol (0.1, 0.2, 0.3, and 0.4% [vol/vol]) in PBS, mixed, and incubated at 37 degrees C. Samples were taken at 0, 1, 5, and 24 h for enumeration. Celery and oysters were inoculated with S. enterica (10(6-7) CFU/ml), treated with 1% cinnamaldehyde or 1% carvacrol, incubated at 4 degrees C, and then sampled for enumeration on days 0 and 3. Both antimicrobials induced complete inactivation of S. enterica in PBS at 0.3 and 0.4% on exposure, and on 0.2% in 1 h. Exposure to cinnamaldehyde at 0.1% inactivated all pathogens at 1 h, and survivors were observed only for Salmonella Newport with 0.1% carvacrol at 1 h. In celery, 1% carvacrol reduced S. enterica populations to below detection on day 0, while 1% cinnamaldehyde reduced populations by 1 and 2.3 log on day 0 and day 3, respectively. In oysters, both antimicrobials caused about 5-log reductions on day 3. These results show the potential antimicrobial effects of carvacrol and cinnamaldehyde against antibiotic-resistant S. enterica in vitro and in foods.
Department of Veterinary Science and Microbiology, University of Arizona, 1117 East Lowell Street, Tucson, Arizona 85721, USA. sadhravi@email.arizona.edu
Sadhana
S
Ravishankar
Libin
L
Zhu
Javier
J
Reyna-Granados
Bibiana
B
Law
Lynn
L
Joens
Mendel
M
Friedman
D000171:Acrolein / Q000031:analogs & derivatives* / Q000494:pharmacology; D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D000077102:Apium / Q000382:microbiology*; D015169:Colony Count, Microbial; D003257:Consumer Product Safety; D000081007:Cymenes; D004305:Dose-Response Relationship, Drug; D024881:Drug Resistance, Bacterial; D005516:Food Microbiology; D005519:Food Preservation / Q000379:methods; D006801:Humans; D008826:Microbial Sensitivity Tests; D039821:Monoterpenes / Q000494:pharmacology*; D010125:Ostreidae / Q000382:microbiology*; D019779:Salmonella enterica / Q000187:drug effects*; D013997:Time Factors
D000900:Anti-Bacterial Agents; D000081007:Cymenes; D039821:Monoterpenes; D000171:Acrolein; C073316:carvacrol; C012843:cinnamaldehyde