Slovak Local Ewe’s Milk Lump Cheese, a Source of Beneficial Enterococcus durans Strain

Abstract

Slovak ewe’s milk lump cheese is produced from unpasteurized ewe’s milk without any added culture. Because of the traditional processing and shaping by hand into a lump, this cheese was given the traditional specialty guaranteed (TSG) label. Up till now, there have existed only limited detailed studies of individual microbiota and their benefits in ewe’s milk lump cheese. Therefore, this study has been focused on the beneficial properties and safety of Enterococcus durans strains with the aim to contribute to basic dairy microbiology but also for further application potential and strategy. The total enterococcal count in cheeses reached 3.93 CFU/g (log 10) ± 1.98 on average. Based on a MALDI-TOF mass spectrometry evaluation, the strains were allotted to the species E. durans (score, 1.781–2.245). The strains were gelatinase and hemolysis-negative (γ-hemolysis) and were mostly susceptible to commercial antibiotics. Among the strains, E. durans ED26E/7 produced the highest value of lactase enzyme β-galactosidase (10 nmoL). ED26E/7 was absent of virulence factor genes such as Hyl (hyaluronidase), IS 16 element and gelatinase (GelE). To test safety, ED26E/7 did not cause mortality in Balb/c mice. Its partially purified bacteriocin substance showed the highest inhibition activity/bioactivity against Gram-positive indicator bacteria: the principal indicator Enterococcus avium EA5 (102,400 AU/mL), Staphylococcus aureus SA5 and listeriae (25,600 AU/mL). Moreover, 16 staphylococci (out of 22) were inhibited (100 AU/mL), and the growth of 36 (out of 51) enterococcal indicators was as well. After further technological tests, E. durans ED26E/7, with its bacteriocin substance, can be supposed as a promising additive to dairy products.

Antilisterial activity of raw sheep milk from two native Epirus breeds: Culture-dependent identification, bacteriocin gene detection and primary safety evaluation of the antagonistic LAB biota

“…Particularly for E. faecium , the absence of the IS16, espA and hyl -like virulence gene markers associated with clinical strains of the species (confirmed in E. faecium 315VR) ( Table 6 ), should be a prerequisite for strains to be considered safe for use in food. Although E. durans has been less investigated than E. faecium , safe E. durans strains of dairy origin have also been selected ( Terzić-Vidojević et al., 2015 ; Laucová et al., 2021 ).…”

Antiparasitic Activity of Enterocin M and Durancin-like from Beneficial Enterococci in Mice Experimentally Infected with Trichinella spiralis

“…E. faecium CCM 8558 is an environmental isolate and deposed in the Czech Culture Collection of Microorganisms, Brno, Czech Republic [25]. Enterococcus durans ED26E/7 was isolated from ewe's milk lump cheese [26].…”

“…It is also a small peptide with a broad antimicrobial spectrum and belongs to the group of pediocinlike enterocins (group II.a) [27]. The partially purified substance for treatment was prepared as follows [26]: The strain was grown in MRS broth (Merck) in an appropriate volume for 18 h at 37 • C. Then it was centrifuged (10,000× g for 30 min at 4 • C). The supernatant (pH 4.2) was precipitated with ammonium sulphate (80% saturation).…”

Lactic Acid Production by Enterococcus durans Is Improved by Cell Recycling and pH Control

“…E. faecium [17] and E. faecalis [20,21] have been investigated for lactic acid production from various substrates. Enterococcus durans can produce chemicals of technological relevance that have already been documented in the literature, such as probiotic and antioxidant capacity and antifungal and antimicrobial capacity [23][24][25][26][27][28]. Most strains of LAB enterococci isolated from milk are homofermentative [13,23].…”