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The transfer via the food chain from animals to humans of microbes that are resistant to antimicrobial agents is of increasing concern. To determine the contributions of nonpathogenic microflora to the occurrence and spread of antibiotic resistance (AR) genes in the food chain, 123 lactic acid bacteria were isolated from 29 samples of raw and processed pork and chicken meat products that had previously tested positive for one or more AR genes that encode clinically relevant ARs: tet(M), tet(O), tet(K), erm(A), erm(B), erm(C), aac (6')-Ie aph (2")-Ia, mecA, and blaZ. All of the isolates were initially tested for their AR gene profiles by PCR. The 59 isolates carrying a tet, erm, or blaZ gene were taken through molecular identification, analyzed by determination of the MIC, and subjected to genetic fingerprinting. Lactococcus garvieae was the predominant species (28 isolates), followed by Lactobacillus plantarum (11 isolates) and L. salivarius (6 isolates), whereas Lactococcus lactis subsp. lactis, Lactobacillus johnsonii, L. reuteri, L. crispatus, and L. brevis were identified at lower frequencies. The tet(M) and erm(B) genes were the most frequently detected. Assessment of multiple resistances in 18 tet positive (tet+) isolates revealed that tet(M) plus erm(B) and tet(K) plus erm(B) were the most frequent AR gene patterns. Partial sequencing of the tet(M) open reading frame of three selected strains showed high sequence similarities (> 99%) with tet(M) genes previously found in human pathogens (Listeria monocytogenes and Neisseria meningitidis). Southern hybridization with plasmid profiles revealed these strains contained tet(M)-carrying plasmids.

Aims:  To study lactic acid bacteria (LAB) and yeast dynamics during the production processes of sweet‐leavened goods manufactured with type I sourdoughs. Methods and Results:  Fourteen sourdough and dough samples were taken from a baking company in central Italy during the production lines of three varieties of Panettone. The samples underwent pH measurements and plating analysis on three solid media. The microbial DNA was extracted from both the (sour)doughs and the viable LAB and yeast cells collected in bulk, and subjected to PCR‐denaturing gradient gel electrophoresis (DGGE) analysis. The molecular fingerprinting of the cultivable plus noncultivable microbial populations provide evidence of the dominance of Lactobacillus sanfranciscensis, Lactobacillus brevis and Candida humilis in the three fermentation processes. The DGGE profiles of the cultivable communities reveal a bacterial shift in the final stages of two of the production processes, suggesting an effect of technological parameters on the selection of the dough microflora. Conclusions:  Our findings confirm the importance of using a combined analytical approach to explore microbial communities that develop during the leavening process of sweet‐leavened goods. Significance and Impact of the Study:  In‐depth studies of sourdough biodiversity and population dynamics occurring during sourdough fermentation are fundamental for the control of the leavening process and the manufacture of standardized, high‐quality products.

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Aims:  Identification and biotyping of lactic acid bacteria (LAB) isolated from raw‐milk Pecorino cheese manufactured in the Marche region (central Italy) for selection of suitable starter cultures or adjuncts. Methods and Results:  Preliminary characterization with morphological and biochemical assays were undertaken for 112 Gram‐positive and catalase‐negative isolates. Unequivocal identification of the isolates was obtained through restriction analysis of the amplified 16S rRNA gene and sequencing of 360–380 bp amplicons. Fifty‐nine isolates belonging to LAB species generally recognized as safe and potentially utilized as starters or flavour‐producing adjuncts were preselected and tested for their acidifying, proteolitic and autolytic activities. Fifty‐five of these isolates were also subject to RAPD (randomly amplified polymorphic DNA) fingerprinting and unweighted pair‐group method with arithmetic averages (UPGMA) cluster analysis for the estimation of genotypic intra‐species variation. As a result, in Pecorino cheese, a heterogeneous lactic acid bacteria population, which includes strains with metabolic characteristics of technological interest, was characterized. Conclusions:  The polyphasic approach proposed allows the bacterial ecology of Pecorino cheese to be investigated and allows to assess the potential role of autochthonous LAB strains for the dairy industry. Significance and Impact of the Study:  The great economic importance of Pecorino cheese encouraged a deeper knowledge of its microbiota, which is known to influence the peculiar sensory properties of this cheese, also in view of its exploitation.