Quantitative Characterization of Geotrichum candidum Growth in Milk

Petra Šipošová,Martina Koňuchová,Ľubomír Valík,Alžbeta Medveďová,Monika Trebichavská

doi:10.3390/app11104619

Petra Šipošová, Martina Koňuchová + Show 3 more

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https://doi.org/10.3390/app11104619

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Abstract

The study of microbial growth in relation to food environments provides essential knowledge for food quality control. With respect to its significance in the dairy industry, the growth of Geotrichum candidum isolate J in milk without and with 1% NaCl was investigated under isothermal conditions ranging from 6 to 37 °C. The mechanistic model by Baranyi and Roberts was used to fit the fungal counts over time and to estimate the growth parameters of the isolate. The effect of temperature on the growth of G. candidum in milk was modelled with the cardinal models, and the cardinal temperatures were calculated as Tmin = −3.8–0.0 °C, Topt = 28.0–34.6 °C, and Tmax = 35.2–37.2 °C. The growth of G. candidum J was slightly faster in milk with 1% NaCl and in temperature regions under 21 °C. However, in a temperature range that was close to the optimum, its growth was slightly inhibited by the lowered water activity level. The present study provides useful cultivation data for understanding the behaviour of G. candidum in milk and can serve as an effective tool for assessing the risk of fungal spoilage, predicting the shelf life of dairy products, or assessing the optimal conditions for its growth in relation to the operational parameters in dairy practices.

Highlights

The close connection of G. candidum with milk and dairy products was reported as early as 1850, when Fresenius isolated and named this microorganism Oidium lactis.G. candidum has undergone extensive taxonomic revision since the genus Geotrichum was firstly erected by Link in 1809, and it is still evolving [1,2,3,4,5]
G. candidum is currently known as a ubiquitous microscopic fungus with a worldwide distribution that is commonly found in soil, water, air, silage, grass, plants, fruits, vegetables, raw milk, and dairy products
Since the lag phase represents the transient period of non-replication during which microorganisms adjust to the new environment, a decrease in the number of viable cells may occur before the exponential phase [41]

Summary

Introduction

The close connection of G. candidum with milk and dairy products was reported as early as 1850, when Fresenius isolated and named this microorganism Oidium lactis.G. candidum has undergone extensive taxonomic revision since the genus Geotrichum was firstly erected by Link in 1809, and it is still evolving [1,2,3,4,5]. The close connection of G. candidum with milk and dairy products was reported as early as 1850, when Fresenius isolated and named this microorganism Oidium lactis. G. candidum is currently known as a ubiquitous microscopic fungus with a worldwide distribution that is commonly found in soil, water, air, silage, grass, plants, fruits, vegetables, raw milk, and dairy products. It is a commensal organism of the human and animal digestive tract [2,3,4,5,6,7].

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