Synergistic effect of pulsed electric fields and CocoanOX 12% on the inactivation kinetics of Bacillus cereus in a mixed beverage of liquid whole egg and skim milk.
With a view to extending the shelf-life and enhancing the safety of liquid whole egg/skim milk (LWE-SM) mixed beverages, a study was conducted with Bacillus cereus vegetative cells inoculated in skim milk (SM) and LWE-SM beverages, with or without antimicrobial cocoa powder. The beverages were treated with Pulsed Electric Field (PEF) technology and then stored at 5 degrees C for 15 days. The kinetic results were modeled with the Bigelow model, Weibull distribution function, modified Gompertz equation, and Log-logistic models. Maximum inactivation registered a reduction of around 3 log cycles at 40 kV/cm, 360 micros, 20 degrees C in both the SM and LWE-SM beverages. By contrast, in the beverages supplemented with the aforementioned antimicrobial compound, higher inactivation levels were obtained under the same treatment conditions, reaching a 3.30 log(10) cycle reduction. The model affording the best fit for all four beverages was the four-parameter Log-logistic model. After 15 days of storage, the antimicrobial compound lowered Bacillus cereus survival rates in the samples supplemented with CocoanOX 12% by a 4 log cycle reduction, as compared to the untreated samples without CocoanOX 12%. This could indicate that the PEF-antimicrobial combination has a synergistic effect on the bacterial cells under study, increasing their sensitivity to subsequent refrigerated storage.
Pina-Pérez
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MC
Instituto de Agroquímica y Tecnología de Alimentos, P.O. Box 73, 46100 Burjassot, Valencia, Spain. conpip@iata.csic.es
Silva-Angulo
A B
AB
Rodrigo
D
D
Martínez-López
A
A
D000818:Animals; D001409:Bacillus cereus; D002417:Cattle; D004574:Electromagnetic Fields; D005516:Food Microbiology; D005519:Food Preservation; D008892:Milk / Q000382:microbiology*; D010063:Ovum / Q000382:microbiology*