Raw milk cheeses play a fundamental role in the Alpine Mountain areas, both for their quality and for the bond they create with the territory and the people who live there. In Trentino, a small province located in the north east Italian Alps, the production of these cheeses is of great gastronomic, ecological and economic importance. The mountains and valleys of Trentino, with their high-altitude pastures, are the heart of this dairy tradition, which produces fine cheeses such as Puzzone di Moena PDO, Vezzena and Trentingrana (Grana Padano) PDO. Dairy production supports the local economy and promotes tourism, creating a virtuous circle that preserves traditions and promotes economic development From a technological point of view, the production of raw milk cheeses derives from a delicate balance of indigenous dairy microbial population, mostly composed of lactic acid bacteria and yeasts and dairy - unwanted microorganisms.

Among the pathogens we can found on dairy, E. coli is the one that in recent years has reported an increase in controls along the supply chain. E. coli is a Gram-negative that is part of the intestinal microbiota. Some E. coli strains are pathogenic; colonize the last part of the bovine rectum, transforming them into vectors. Many types of pathogenic E. coli have been isolated from cheese, such as enteropathogenic E. coli (EPEC), enterotoxigenic E. coli (ETEC), enteroaggregative E. coli (EAEC), enteroinvasive E. coli (EIEC), diffuse adherent E. coli (DAEC), enteroaggregative-hemorrhagic E. coli (EAHEC) and Shiga-toxin producing E. coli (STEC).

STEC is the cause of uremic haemolytic syndrome (HUS) as the two Shiga-toxins (Stx1, Stx2) can bring to a cytotoxic effect on epithelial and endothelial cells of the intestine. From 2020 to 2024, a total of forty-one alerts" regarding the presence of this pathogen in dairy products has been reported by the European Rapid Alert System for Food and Feed (RASFF), three of which were attributable to Italian products.

In Trentino, the Trentingrana – COnsorzio dei CAseifici Sociali Trentini (CONCAST) represents the territorial reference point for the dairy industry. Every day, approximately 82% of the milk produced in the province of Trento is collected and processed by dairy cooperatives associated with CONCAST.

In 2017 the control activity of Trentino dairy production was implemented by adding the search for STEC in all raw milk dairy products; Moreover, since 2023 CONCAST have been implemented a new “STEC guideline” that focus the STEC control on all cheese- curds of raw milk on short and medium-aged cheeses; nowadays, thousands of batches of raw milk products have been checked for STEC presence by the accredited CONCAST laboratory.

With those activities, CONCAST has partly filled a regulatory gap for the STEC risk Assessment on dairy industry. Thanks to the CONCAST “STEC guideline” Trentino has become a reference for other Italian regions for the production chain controls and the public health preservation

Nicola Cologna

Lab Quality Manager

Trentingrana Concast SCA