Modelling the effect of temperature, pH, water activity, and organic acids on the germination time of Penicillium camemberti and Penicillium roqueforti conidia

• Published in: International journal of food microbiology 2017-01, Vol.240, p.124-130
• Main Authors: Kalai, Safaa, Anzala, Lexane, Bensoussan, Maurice, Dantigny, Philippe
• Format: Article
• Language: English
• Subjects: Acids; Cheese; Cheese - microbiology; Conidia; Environmental factors; Food engineering; Food Microbiology - methods; Freezing; Freezing point; Fungal starters; Fungi; Germination; Hydrogen ions; Hydrogen-Ion Concentration; Lactic acid; Lactic Acid - pharmacology; Life Sciences; Melting points; Microbial Sensitivity Tests; Minimum inhibitory concentration; Models, Biological; Mycelium - growth & development; Optimization; Organic acids; Organic Chemicals - pharmacology; Penicillium - growth & development; pH effects; Predictive mycology; Propionates - pharmacology; Propionic acid; Sodium Chloride - pharmacology; Species; Spores, Fungal - growth & development; Temperature; Temperature effects; Water - pharmacology; Water activity
• ISSN: 0168-1605; 1879-3460
• DOI: 10.1016/j.ijfoodmicro.2016.03.024

In this study, the influence of environmental factors on the germination time of Penicillium camemberti and Penicillium roqueforti conidia was evaluated. To do so, the effects of i/temperature, pH, water activity, and ii/organic acids were determined using models based on i/cardinal values, and ii/minimum inhibitory concentration (MIC) respectively. Cardinal values for germination of conidia were not observed to be species dependent. Minimum temperatures were estimated to be below the freezing point, with an optimum of 26.9°C, and a maximum of 33.5°C. For both species, minimal and optimal aw values were found to be 0.83 and 0.99, respectively, while for pH these values corresponded to 2.9, and 5.6. MIC values could not be determined for lactic acid because conidia of both species germinated in up to 1M concentrations, the highest concentration tested. At pH5.6, P. camemberti (MIC=0.197M) was more sensitive to propionic acid than P. roqueforti (MIC=0.796M). •Penicillium camemberti and Penicillium roqueforti exhibited the same cardinal values for T, pH, and aw.•Both the species were psychrotrophic.•P. camemberti was more sensitive to lactic acid and propionic acid than P. roqueforti.