6533b829fe1ef96bd128acdb
RESEARCH PRODUCT
Animal rennets as sources of dairy lactic acid bacteria
Isabella MancusoAntonietta La StoriaCiro SanninoDanilo ErcoliniMaria Luisa ScatassaGiancarlo MoschettiMargherita CruciataFrancesca De FilippisLuca Settannisubject
Streptococcus thermophilusColony CountColony Count MicrobialApplied Microbiology and BiotechnologyAcidification; Animal rennet pastes; Autolysis; Lactic acid bacteria; Microbial ecology; PyrosequencingMicrobial ecologyMicrobialCheeseRNA Ribosomal 16SLactobacillusEnterococcus casseliflavusLactic acid bacteriaCluster AnalysisPhylogenyEcologybiologyLactobacillus crispatusBacterialAnimal rennet pastefood and beveragesPyrosequencingHydrogen-Ion ConcentrationAutolysiBiotaAnimals; Cluster Analysis; Colony Count Microbial; DNA Bacterial; DNA Ribosomal; Enterococcus; Hydrogen-Ion Concentration; Lactobacillus; Microbial Viability; Milk; Molecular Sequence Data; Phylogeny; RNA Ribosomal 16S; Sequence Analysis DNA; Biota; ChymosinMilkSequence AnalysisChymosinBiotechnologyDNA Bacterial16SMolecular Sequence DataDNA RibosomalEnterococcus faecalisMicrobiologyAcidificationAnimalsRibosomalMicrobial ViabilitySequence Analysis DNADNAbiology.organism_classificationLactobacillus reuteriLactobacillusEnterococcusFood MicrobiologyRNAMetagenomicsEnterococcusFood ScienceEnterococcus faeciumSettore AGR/16 - Microbiologia Agrariadescription
ABSTRACT The microbial composition of artisan and industrial animal rennet pastes was studied by using both culture-dependent and -independent approaches. Pyrosequencing targeting the 16S rRNA gene allowed to identify 361 operational taxonomic units (OTUs) to the genus/species level. Among lactic acid bacteria (LAB), Streptococcus thermophilus and some lactobacilli, mainly Lactobacillus crispatus and Lactobacillus reuteri , were the most abundant species, with differences among the samples. Twelve groups of microorganisms were targeted by viable plate counts revealing a dominance of mesophilic cocci. All rennets were able to acidify ultrahigh-temperature-processed (UHT) milk as shown by pH and total titratable acidity (TTA). Presumptive LAB isolated at the highest dilutions of acidified milks were phenotypically characterized, grouped, differentiated at the strain level by randomly amplified polymorphic DNA (RAPD)-PCR analysis, and subjected to 16S rRNA gene sequencing. Only 18 strains were clearly identified at the species level, as Enterococcus casseliflavus , Enterococcus faecium , Enterococcus faecalis , Enterococcus lactis , Lactobacillus delbrueckii , and Streptococcus thermophilus , while the other strains, all belonging to the genus Enterococcus , could not be allotted into any previously described species. The phylogenetic analysis showed that these strains might represent different unknown species. All strains were evaluated for their dairy technological performances. All isolates produced diacetyl, and 10 of them produced a rapid pH drop in milk, but only 3 isolates were also autolytic. This work showed that animal rennet pastes can be sources of LAB, mainly enterococci, that might contribute to the microbial diversity associated with dairy productions.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 2014-04-01 |