Seasonal variation in the Canastra cheese mycobiota

Canastra cheese is the most well-known artisanal cheese produced in Brazil. Although its production includes a step to remove fungi from the cheese surface, in recent years some cheesemakers have preserved the autochthonous fungi grown during ripening due to an interest in the sensory characteristics attributed to these microorganisms. In this work, the mycobiota of artisanal cheeses produced in the Canastra region was characterized based on ITS marker gene analysis. A total of 96 artisanal cheeses from 16 different farms across 9 cities were collected during two different periods (dry and wet seasons). The Canastra cheese mycobiota was significantly impacted by the season, the city of production and the farm but altitude did not affect the fungal community of the cheeses analyzed. Debaryomyces prosopidis was most abundant in the majority of samples across both seasons. During the wet season, Trichosporon asahii, Kluyveromyces lactis and Fusarium solani were the next most abundant species, followed by Torulaspora delbrueckii and Acremonium citrinum. These results highlight the importance of manufacturing practices and seasonality on the fungal composition of Canastra cheeses. These insights are particularly important in light of recent new regulation in Brazil, removing previous obstacles for surface fungi to persist on cheese. These new regulations will allow new approaches to cheese production, and ultimately, novel products.

Microbiological aspects of the biofilm on wooden utensils used to make a Brazilian artisanal cheese

The artisanal Minas cheese is produced from raw cow’s milk and wooden utensils were employed in its manufacture, which were replaced by other materials at the request of local laws. This substitution caused changes in the traditional characteristics of cheese. Due to the absence of scientific studies indicating the microbial composition of biofilms formed on wooden forms, tables and shelves used in these cheese production, the present work evaluated the counts of Staphylococcus aureus, Escherichia coli, coliforms at 32 °C, yeasts, presumptive mesophilic Lactobacillus spp. and Lactococcus spp. in these biofilms, milk, whey endogenous culture and ripened cheese in two traditional regions: Serro and Serra da Canastra. Also, we checked for the presence of Salmonella sp. and Listeria monocytogenes in the ripened cheeses. The ultra structure of the biofilms was also assessed. Counts above legislation (> 2 log cfu/mL) for the pathogens evaluated were found in milk samples from both regions. Only one shelf and one form from Serro were above limits proposed (5 cfu/cm² for S. aureus and E. coli and 25 cfu/cm² for coliforms) in this study for contaminants evaluated. In Canastra, few utensils presented safe counting of pathogens. There was no Salmonella sp. and Listeria monocytogenes in the cheeses after ripening. Thus, the quality of the cheese is related to improving the microbiological quality of milk, implementation and maintenance of good manufacturing practices, correct cleaning of wooden utensils, and not its replacement.