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The combined effect of nisin, moderate heating and high hydrostatic pressure on the inactivation of Bacillus sporothermodurans spores
Author(s) -
Aouadhi C.,
Simonin H.,
Mejri S.,
Maaroufi A.
Publication year - 2013
Publication title -
journal of applied microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.889
H-Index - 156
eISSN - 1365-2672
pISSN - 1364-5072
DOI - 10.1111/jam.12220
Subject(s) - nisin , spore , hydrostatic pressure , food science , central composite design , response surface methodology , chemistry , endospore , water activity , microbiology and biotechnology , biology , chromatography , thermodynamics , water content , antimicrobial , physics , geotechnical engineering , engineering
Aims To investigate the combined effect of hydrostatic pressure ( HP ), moderate temperature and nisin on the inactivation of B acillus sporothermodurans spores which are known to be contaminant of dairy products and to be extremely heat‐resistant. Methods and Results A central composite experimental design with three factors, using response surface methodology, was used. By analysing the response surfaces and their corresponding contour plots, an interesting interaction with the three factors was observed. The inactivation observed was shown to be well fitted with values predicted by the quadratic equation, since the adjusted determination coefficient ( R adj 2 ) was 0·979. The optimum process parameters for a 5‐log spores ml −1 reduction of B . sporothermodurans spores were obtained, 472 MPa/53°C for 5 min in presence of 121 UI ml −1 of nisin. Conclusion Nisin and temperature treatments improve the effectiveness of pressure in the inactivation of highly heat‐resistant spores of B . sporothermodurans . Significance and Impact of the Study This study shows the potential of using high HP for a short time (5 min) in combination with moderate temperature and nisin to inactivate B . sporothermodurans spores in milk. Such treatments could be applied by the dairy industry to ensure the commercial sterility of UHT milk.