Inactivation of barotolerant Listeria monocytogenes in sausage by combination of high-pressure processing and food-grade additives.
Food-grade additives were used to enhance the efficacy of high-pressure processing (HPP) against barotolerant Listeria monocytogenes. Three strains of L. monocytogenes (Scott A, OSY-8578, and OSY-328) were compared for their sensitivity to HPP, nisin, tert-butylhydroquinone (TBHQ), and their combination. Inactivation of these strains was evaluated in 0.2 M sodium phosphate buffer (pH 7.0) and commercially sterile sausage. A cell suspension of L. monocytogenes in buffer (10(9) CFU/ml) was treated with TBHQ at 100 ppm, nisin at 100 IU/ml, HPP at 400 MPa for 5 min, and combinations of these treatments. Populations of strains Scott A, OSY-8578, and OSY-328 decreased 3.9, 2.7, and 1.3 log with HPP alone and 6.4, 5.2, and 1.9 log with the HPP-TBHQ combination, respectively. Commercially sterile sausage was inoculated with the three L. monocytogenes strains (10(6) to 10(7) CFU/g) and treated with selected combinations of TBHQ (100 to 300 ppm), nisin (100 and 200 ppm), and HPP (600 MPa, 28 degrees C, 5 min). Samples were enriched to detect the viability of the pathogen after the treatments. Most of the samples treated with nisin, TBHQ, or their combination were positive for L. monocytogenes. HPP alone resulted in a modest decrease in the number of positive samples. L. monocytogenes was not detected in any of the inoculated commercial sausage samples after treatment with HPP-TBHQ or HPP-TBHQ-nisin combinations. These results suggest that addition of TBHQ or TBHQ plus nisin to sausage followed by in-package pressurization is a promising method for producing Listeria-free ready-to-eat products.
Chung
Yoon-Kyung
YK
Department of Food Science and Technology, Ohio State University, Columbus, Ohio 43210, USA.
Vurma
Mustafa
M
Turek
Evan J
EJ
Chism
Grady W
GW
Yousef
Ahmed E
AE
D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D015169:Colony Count, Microbial; D003257:Consumer Product Safety; D005503:Food Additives / Q000494:pharmacology*; D005511:Food Handling / Q000379:methods*; D005516:Food Microbiology; D005525:Food-Processing Industry / Q000592:standards; D006801:Humans; D006873:Hydroquinones / Q000494:pharmacology; D008089:Listeria monocytogenes / Q000254:growth & development*; D008461:Meat Products / Q000382:microbiology*; D009561:Nisin / Q000494:pharmacology; D011312:Pressure; D013552:Swine; D013997:Time Factors
D000900:Anti-Bacterial Agents; D005503:Food Additives; D006873:Hydroquinones; D009561:Nisin; C018855:2-tert-butylhydroquinone