title: The microbiota of high-moisture mozzarella cheese produced with different acidification methods.
abstract: The microbiota of high-moisture Mozzarella cheese made from cow's milk and produced with different acidification methods was evaluated at the end of refrigerated storage by pyrosequencing of the 16S rRNA gene. The cheeses were clearly separated on the basis of the acidification methods. Cheeses produced with the addition of starters were dominated by Streptococcus thermophilus, but a variety of lactic acid bacteria and spoilage microorganisms appeared at low levels (0.01-1%). Cheeses produced by direct addition of citric acid were dominated by a diverse microbiota, including both lactic acid bacteria and psychrotrophic γ-proteobacteria. For five brands the acidification system was not declared on the label: the microbiota was dominated by thermophilic lactic acid bacteria (S. thermophilus, Lactobacillus delbrueckii, Lactobacillus helveticus) but a variety of other subdominant lactic acid bacteria, psychrotrophs and Enterobacteriaceae were present, with a diversity comparable or higher to cheeses produced by direct acid addition. This led to the conclusion that undefined starters were used for acidification. Both ordination methods and network analysis were used for the representation of beta-diversity: matrix cluster analysis, principal coordinate analysis and OTU networks uncovered different aspects of the microbial community structure. For three cheese brands both biological replicates (cheeses from different lots) and technical replicates (replicate cheeses from the same lot) were analyzed. Repeatability was acceptable for OTUs appearing at frequencies >1%, but was low otherwise. A linear mixed model showed that the starter system was responsible for most differences related to dairies, while difference due to psychrotrophic contaminants was more related to lot-to-lot variability.
authors.affiliation: Scuola di Scienze Agrarie, Forestali, Alimentari ed Ambientali, Università degli Studi della Basilicata, Potenza, Italy.
authors.forename: Angela
authors.initials: A
authors.lastname: Guidone
authors.affiliation: Istituto di Scienze dell'Alimentazione, CNR, Avellino, Italy.
authors.forename: Teresa
authors.initials: T
authors.lastname: Zotta
authors.affiliation: Scuola di Scienze Agrarie, Forestali, Alimentari ed Ambientali, Università degli Studi della Basilicata, Potenza, Italy.
authors.forename: Attilio
authors.initials: A
authors.lastname: Matera
authors.affiliation: Scuola di Scienze Agrarie, Forestali, Alimentari ed Ambientali, Università degli Studi della Basilicata, Potenza, Italy. Electronic address: annamaria.ricciardi@unibas.it.
authors.forename: Annamaria
authors.initials: A
authors.lastname: Ricciardi
authors.affiliation: Dipartimento di Agraria, Università degli Studi di Napoli "Federico II", Portici (NA), Italy.
authors.forename: Francesca
authors.initials: F
authors.lastname: De Filippis
authors.affiliation: Dipartimento di Agraria, Università degli Studi di Napoli "Federico II", Portici (NA), Italy.
authors.forename: Danilo
authors.initials: D
authors.lastname: Ercolini
authors.affiliation: Scuola di Scienze Agrarie, Forestali, Alimentari ed Ambientali, Università degli Studi della Basilicata, Potenza, Italy; Istituto di Scienze dell'Alimentazione, CNR, Avellino, Italy.
authors.forename: Eugenio
authors.initials: E
authors.lastname: Parente
mesh_terms: D000818:Animals; D001483:Base Sequence; D002417:Cattle; D002611:Cheese / Q000382:microbiology*; D019343:Citric Acid / Q000737:chemistry; D004269:DNA, Bacterial / Q000235:genetics; D004755:Enterobacteriaceae / Q000302:isolation & purification; D005260:Female; D059014:High-Throughput Nucleotide Sequencing; D019344:Lactic Acid / Q000737:chemistry; D007778:Lactobacillus / Q000302:isolation & purification*; D064307:Microbiota / Q000235:genetics*; D008892:Milk / Q000382:microbiology; D020560:Proteobacteria / Q000302:isolation & purification; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017422:Sequence Analysis, DNA; D048249:Streptococcus thermophilus / Q000302:isolation & purification*
chemical_list: D004269:DNA, Bacterial; D012336:RNA, Ribosomal, 16S; D019343:Citric Acid; D019344:Lactic Acid
keywords: 16S rRNA gene high-throughput sequencing; Acidification method; High-moisture mozzarella cheese; Microbiota