title: Strategies to increase the stability of intermediate moisture foods towards Zygosaccharomyces rouxii: the effect of temperature, ethanol, pH and water activity, with or without the influence of organic acids.
abstract: Intermediate moisture foods (IMF) are in general microbiologically stable products. However, due to health concerns consumer demands are increasingly forcing producers to lower the fat, sugar and preservatives content, which impede the stability of the IMF products. One of the strategies to counteract these problems is the storage of IMF products at lower temperatures. Thorough knowledge on growth/no growth boundaries of Zygosaccharomyces rouxii in IMF products, also at different storage temperatures is an important tool for ensuring microbiologically stability. In this study, growth/no growth models for Z. rouxii, developed by Vermeulen et al. (2012) were further extended by incorporating the factor temperature. Three different data sets were build: (i) without organic acids, (ii) with acetic acid (10,000 ppm on product basis) and (iii) with sorbic acid (1500 ppm on product basis). For each of these data sets three different growth/no growth models were developed after 30, 60 and 90 days. The results show that the influence of temperature is only significant in the lower temperature range (8-15 °C). Also, the effect of pH is negligible (pH 5.0-6.2) unless organic acids are present. More specific, acetic acid had only an additive effect to ethanol and aw at low pH, whereas sorbic acid had also an additive effect at the higher pH values. For incubation periods longer than 30 days the growth/no growth boundary remained stable but enlarged gradually between day 60 and 90, except for the lower temperature range (<12 °C) where the boundary shifts to more stringent environmental conditions.
authors.affiliation: CPMF (2)- Flemish Cluster Predictive Microbiology in Foods, Belgium; LFMFP, Laboratory of Food Microbiology and Food Preservation, Department of Food Safety and Food Quality, Ghent University, Coupure Links 653, 9000 Ghent, Belgium.
authors.forename: A
authors.initials: A
authors.lastname: Vermeulen
authors.affiliation: Section of Food Microbiology, Department of Food Science, University of Copenhagen, Rolighedsvej 30, 1958 Frederiksberg, Denmark.
authors.forename: C L
authors.initials: CL
authors.lastname: Marvig
authors.affiliation: LFMFP, Laboratory of Food Microbiology and Food Preservation, Department of Food Safety and Food Quality, Ghent University, Coupure Links 653, 9000 Ghent, Belgium.
authors.forename: J
authors.initials: J
authors.lastname: Daelman
authors.affiliation: CPMF (2)- Flemish Cluster Predictive Microbiology in Foods, Belgium; LFMFP, Laboratory of Food Microbiology and Food Preservation, Department of Food Safety and Food Quality, Ghent University, Coupure Links 653, 9000 Ghent, Belgium.
authors.forename: R
authors.initials: R
authors.lastname: Xhaferi
authors.affiliation: Section of Food Microbiology, Department of Food Science, University of Copenhagen, Rolighedsvej 30, 1958 Frederiksberg, Denmark.
authors.forename: D S
authors.initials: DS
authors.lastname: Nielsen
authors.affiliation: CPMF (2)- Flemish Cluster Predictive Microbiology in Foods, Belgium; LFMFP, Laboratory of Food Microbiology and Food Preservation, Department of Food Safety and Food Quality, Ghent University, Coupure Links 653, 9000 Ghent, Belgium. Electronic address: Frank.Devlieghere@UGent.be.
authors.forename: F
authors.initials: F
authors.lastname: Devlieghere
mesh_terms: D019342:Acetic Acid / Q000494:pharmacology*; D000431:Ethanol / Q000494:pharmacology; D005516:Food Microbiology; D005520:Food Preservatives; D006863:Hydrogen-Ion Concentration; D016015:Logistic Models; D008962:Models, Theoretical; D013011:Sorbic Acid / Q000494:pharmacology*; D013696:Temperature; D014867:Water / Q000378:metabolism; D020068:Zygosaccharomyces / Q000187:drug effects / Q000254:growth & development*
chemical_list: D005520:Food Preservatives; D014867:Water; D000431:Ethanol; D019342:Acetic Acid; D013011:Sorbic Acid
keywords: Logistic regression; Temperature; Zygosaccharomyces rouxii