Impact of pre-treatment and heat treatment (sublethal injury) on the survival of Streptococcus salivarius K12 cells in a model food product
The objective of this study was to investigate the impact of a processing step involving heat (61ºC for 24 minutes or 66ºC for 2.4 minutes) on the survival of S. salivarius K12 dried cells in model cereal bars held at 25oC for up to 49 days. The result showed the survival of K12 after heat treated had the D value was 22 days compared of 38 days for unheated. The further study investigated that the impact of a pre-heating step (50ºC for 24 hours or 56ºC for 24 hours) on the subsequent survival of unheated or heated (61ºC for 24 minutes) S. salivarius K12 dried cells after their addition to model cereal bars. The result showed K12 after pre-heated at 50ºC then heated had D value of 28 days and pre-heated at 56ºC had D value 31 days.
Advisor: Bremer, Phil
Degree Name: Master of Science
Degree Discipline: Food Science
Publisher: University of Otago
Keywords: sublethal; pre-heated; survival; probiotics
Research Type: Thesis