title: Microbial dynamics during shelf-life of industrial Ricotta cheese and identification of a Bacillus strain as a cause of a pink discolouration.
abstract: Dairy products are perishable and have to be preserved from spoilage during the food chain to achieve the desired shelf-life. Ricotta is a typical Italian soft dairy food produced by heat coagulation of whey proteins and is considered to be a light and healthy product. The shelf-life of Ricotta could be extended, as required by the international food trade market; however, heat resistant microflora causes spoilage and poses issues regarding the safety of the product. Next-generation sequencing (NGS) applied to the Ricotta samples defined the composition of the microbial community in-depth during the shelf-life. The analysis demonstrated the predominance of spore-forming bacteria throughout the shelf-life, mostly belonging to Bacillus, Paenibacillus and Clostridium genera. A strain involved in spoilage and causing a pink discolouration of Ricotta was isolated and characterised as Bacillus mycoides/weihenstephanensis. This is the first report of a food discolouration caused by a toxigenic strain belonging to the Bacillus cereus group that resulted the predominant strain in the community of the defective ricotta. These results suggest that the processing of raw materials to eliminate spores and residual microflora could be essential for improving the quality and the safety of the product and to extend the shelf-life of industrial Ricotta.
authors.affiliation: BMR Genomics, Via Redipuglia 21a, Padova, Italy.
authors.forename: E
authors.initials: E
authors.lastname: Sattin
authors.affiliation: Department of Comparative Biomedicine and Food Science, University of Padova, Viale dell'Università, 16, Legnaro, 35020, Padova, Italy.
authors.forename: N A
authors.initials: NA
authors.lastname: Andreani
authors.affiliation: Department of Comparative Biomedicine and Food Science, University of Padova, Viale dell'Università, 16, Legnaro, 35020, Padova, Italy.
authors.forename: L
authors.initials: L
authors.lastname: Carraro
authors.affiliation: Department of Comparative Biomedicine and Food Science, University of Padova, Viale dell'Università, 16, Legnaro, 35020, Padova, Italy.
authors.forename: L
authors.initials: L
authors.lastname: Fasolato
authors.affiliation: Department of Comparative Biomedicine and Food Science, University of Padova, Viale dell'Università, 16, Legnaro, 35020, Padova, Italy.
authors.forename: S
authors.initials: S
authors.lastname: Balzan
authors.affiliation: Department of Comparative Biomedicine and Food Science, University of Padova, Viale dell'Università, 16, Legnaro, 35020, Padova, Italy.
authors.forename: E
authors.initials: E
authors.lastname: Novelli
authors.affiliation: Department of Agronomy, Food, Natural Resources, Animals, Environment (DAFNAE), University of Padova, Viale dell'Università, 16, Legnaro, 35020, Padova, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Squartini
authors.affiliation: BMR Genomics, Via Redipuglia 21a, Padova, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Telatin
authors.affiliation: BMR Genomics, Via Redipuglia 21a, Padova, Italy.
authors.forename: B
authors.initials: B
authors.lastname: Simionati
authors.affiliation: Department of Comparative Biomedicine and Food Science, University of Padova, Viale dell'Università, 16, Legnaro, 35020, Padova, Italy. Electronic address: barbara.cardazzo@unipd.it.
authors.forename: B
authors.initials: B
authors.lastname: Cardazzo
mesh_terms: D000818:Animals; D001407:Bacillus / Q000145:classification / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D001419:Bacteria / Q000145:classification / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D002417:Cattle; D002611:Cheese / Q000032:analysis / Q000382:microbiology*; D061353:Food Storage; D008892:Milk / Q000382:microbiology; D010860:Pigments, Biological / Q000378:metabolism*
chemical_list: D010860:Pigments, Biological
keywords: Microbial community; Pink discolouration; Ricotta; Shelf-life; Spore forming bacteria