Isolation and Identification of Lactic Acid Bacteria from Natural Whey Cultures of Buffalo and Cow Milk.

Rosangela Marasco,Nicoletta Campolattano,Mariagiovanna Gazzillo,Lidia Muscariello,Margherita Sacco

doi:10.3390/foods11020233

Abstract

In southern Italy, some artisanal farms produce mozzarella and caciocavallo cheeses by using natural whey starter (NWS), whose microbial diversity is responsible for the characteristic flavor and texture of the final product. We studied the microbial community of NWS cultures of cow’s milk (NWSc) for the production of caciocavallo and buffalo’s milk (NWSb) for the production of mozzarella, both from artisanal farms. Bacterial identification at species and strain level was based on an integrative strategy, combining culture-dependent (sequencing of the 16S rDNA, species/subspecies-specific Polymerase Chain Reaction (PCR) and clustering by Random Amplified Polymorphic DNA-Polymerase Chain Reaction (RAPD-PCR) and culture-independent (next-generation sequencing analysis, NGS) approaches. Results obtained with both approaches showed the occurrence of five species of lactic acid bacteria in NWSb (Lactococcus lactis subsp. lactis, Lactobacillus fermentum, Streptococcus thermophilus, Lactobacillus delbrueckii, and Lactobacillus helveticus) and five species in NWSc (Lc. lactis subsp. lactis, Enterococcus faecium, and S. thermophilus, Lb. helveticus, and Lb. delbrueckii), with the last two found only by the NGS analysis. Moreover, RAPD profiles, performed on Lc. lactis subsp. lactis different isolates from both NWSs, showed nine strains in NWSb and seven strains in NWSc, showing a microbial diversity also at strain level. Characterization of the microbiota of natural whey starters aims to collect new starter bacteria to use for tracing microbial community during the production of artisanal cheeses, in order to preserve their quality and authenticity, and to select new Lactic Acid Bacteria (LAB) strains for the production of functional foods.

Highlights

Cheese is a very valuable food product for its high nutrition value, its versatility in the end use, and its organoleptic properties
In southern Italy, some artisanal farms produce mozzarella and caciocavallo cheeses by using natural whey starter (NWS), whose microbial diversity is responsible for the characteristic flavor and texture of the final product
Characterization of the microbiota of natural whey starters aims to collect new starter bacteria to use for tracing microbial community during the production of artisanal cheeses, in order to preserve their quality and authenticity, and to select new Lactic Acid Bacteria (LAB) strains for the production of functional foods

Summary

Introduction

Cheese is a very valuable food product for its high nutrition value, its versatility in the end use, and its organoleptic properties. In spite of the development of different standard procedures for industrial manufacturing of Pasta filata cheese, the production of mozzarella and caciocavallo in Campania (southern Italy) is still largely based on artisanal activities of small dairy farms. The microbial biodiversity of NWSs is higher than that present in SLABs. the microbiota of various artisanal mozzarella and caciocavallo cheeses has been determined by different molecular methods based on culture-dependent or -independent approaches [11,12,13,14,15,16]. The culture-independent metagenomic analysis has been applied to studies on Pasta filata cheeses acidified with either SLAB or with NWS [17,18,19,20] This approach overcomes the problem of underestimation of the microbial diversity, which is often encountered when culture-dependent methods are used. On the light of the assessed value of some LAB strains, studies on isolates from NWS may be functional to the implementation of new promising probiotic strains

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Conclusion