Use of chitosan and tannins as alternatives to antibiotics to control mold growth on PDO Pecorino Toscano cheese rind

The fungal microbiota usually growing on the cheese surface during ripening processes promote rind formation and the development of organoleptic characteristics, imparting positive sensory attributes to cheeses. As cheese contamination may also occur by undesirable molds, specific actions for preventing their growth are usually realized in dairy industries by using the antibiotic natamycin, which may represent a risk factor for human health and environmental sustainability. Here, agroindustrial by-products with natural antimicrobial properties, i.e. tannins and chitosan, were tested in a cheese-making trial producing PDO Tuscan pecorino cheese. Morphological and molecular methods revealed that the main components of rind fungal communities of PDO Tuscan pecorino cheese were represented by P. solitum, P. discolour and P. verrucosum. The use of chitosan on cheese rinds did not significantly affect the composition of rind fungal communities developing during the whole ripening process compared with controls treated with natamycin, whose numbers ranged from 3.4±1.3x103 to 3.2±1.8x104 and from 6.3±3.5x102 to 4.0±1.5x104, respectively. Overall, grape marc tannins and chitosan did not significantly affect the number and composition of fungal communities developing during PDO Pecorino Toscano cheese ripening, as well as its physical, chemical and nutritional profiles, showing that they may represent effective alternatives to the antibiotic natamycin

STILNOVO: sustainability and innovation technology for dairy sheep production, an innovation transfer project in Tuscany

In Tuscany, the ewes farming for dairy production is facing low incomes and scarce competitiveness of farms, mainly due to a poor level of innovation concerning the management of both the cropping and animal systems. Consequently, in the recent years, the milk quality decreased preventing the production of high-quality dairy products. Moreover, in the Mediterranean, climate change is leading to an increase frequency of extreme rainfall events, raising the risk of soil loss by water. Thus, novel cropping systems have to be more resilient to these new conditions to guarantee the conservation of farm profitability and natural resources. Within this framework, the STILNOVO project (sustainability and innovation technology for dairy sheep production) is aiming at: (i) improving milk quality at competitive costs, (ii) increasing the efficiency of the grassland-based production by rational management, (iii) optimizing the ewes feeding, (iv) decreasing the risk of contamination by clostridia bacteria and (v) optimizing the use of bio-active compounds for cheese aging. Keywords: milk quality, legume, soil erosion, extension services, resilience

Characterization of the microbial community in ripened Pecorino Toscano cheese affected by pink discoloration

Pink discoloration defect can cause economic losses for cheese producers due to the impossibility to sell the defected cheese, but few knowledge is currently available on the causes of this defect. To gain more insight on the causes that lead to the formation of pink discoloration in Pecorino Toscano cheese with the Protected Designation of Origin (PDO) status, the bacterial community in defected and not defected cheese was characterized by high-throughput sequencing of bacterial 16S rRNA gene. The bacterial community in the defected cheese significantly differed compared to the control. The relative abundance of the genera Acidipropionibacterium, Enterococcus, Escherichia/Shigella, Lactobacillus, Lentilactobacillus and Propionibacterium was higher in the cheese with pink discoloration defect. The concentration of short chain fatty acids and of lactic acid in cheese was measured and a shift towards the production of propionate in the cheese with pink discoloration defect was observed. Furthermore, the possible involvement of microbially produced vitamin B12 in the formation of pink discoloration was not supported by the data, since a tendency to a lower concentration of vitamin B12 was measured in the defected cheese compared to the control