abstract
- In this study, the heat resistance of S. aureus in goats’ raw milk subjected to thermisation temperatures was characterised through tests at various temperatures and modelling the survival curves using the Weibull model, through a two-step and an omnibus approach, which can model a full dataset covering all experimental conditions in one step. The fitting capacity of the secondary models obtained from the two-step approach was reasonable (adj. R2 > 0.639) and both demonstrated the negative linear effects of temperature on ̅̅̅ χ √ (p = 0.0004) and ̅̅̅ β √ (p = 0.017). The fitting capacity of the omnibus model was more satisfactory (adj. R2 = 0.996) and also hinted at the negative linear effect of temperature on ̅̅̅ χ √ (p < 0.0001), with the added advantage that, in this model, random effects can be used to account for the variability in the parameters. Our study estimated the significant inactivation parameters and established a model capable of predicting S. aureus behaviour at various temperatures. This information is useful to create time-temperature tables to reach target log reductions of S. aureus in goats’ raw milk to be used by artisanal cheesemakers; hence providing an opportunity to increase the microbiological safety of cheeses made from unpasteurised milk.
- The authors are grateful to the Foundation for Science and Technology (FCT, Portugal) for financial support through national funds FCT/MCTES (PIDDAC) to CIMO (UIDB/00690/2020 and UIDP/00690/ 2020) and SusTEC (LA/P/0007/2020). They are also grateful to the EU PRIMA program and the Portuguese Foundation for Science and Technology (FCT) for funding the ArtiSaneFood project (PRIMA/0001/ 2018). This study was supported by FCT under the scope of the strategic funding of the UIDB/04469/2020 unit and BioTecNorte operation (NORTE-01–0145-FEDER-000004) funded by the European Regional Development Fund under the scope of Norte2020—Programa Operacional Regional do Norte. B. N. Silva acknowledges the financial support provided by FCT through the Ph.D. grant SFRH/BD/137801/2018.