Presence of Enterococci in Raw Cow's Milk and “Puzzone DI Moena” Cheese (original) (raw)
Related papers
A survey of the enterococci isolated from an artisanal Italian goat's cheese (semicotto caprino)
Journal of Applied Microbiology, 2000
Enterococci were isolated from semicotto caprino cheese, a traditional cheese produced in Southern Italy: they were a signi®cant part of the microbial population of this cheese, con®rming the importance of the presence of these micro-organisms during cheese-making and ripening. They were also identi®ed and studied for their phenotypic and genotypic characteristics: Enterococcus faecalis and Ent. faecium were the most frequently isolated species, followed by Ent. durans, Ent. hirae and Ent. gallinarum. None of the isolates showed lipolytic activity, whereas they were characterized by a relevant proteolytic activity as well as an antagonistic activity towards Listeria innocua. One strain of Ent. gallinarum showed a low-level resistance to vancomycin, while six out of the 79 Ent. faecalis strains possessed b-haemolysis reaction. The highest acidifying potential in skim milk was obtained by Ent. faecalis isolates. Thirty enterococcal strains representative of the different species at different ripening times were analysed by means of RAPD-PCR, and revealed species-speci®c pro®les for all the considered species.
Enterococci in cheese - phenotypization and antibiotic resistance
2004
The material of investigation was consisted of samples of fresh and ripened cheeses made from raw and cooked milk subjected to rennet or acid coagulation. The primary isolation of enterococci was carried out on kanamycin-aesculine-azide agar at 37 °C and 42 °C during 24 hours. It was isolated totally 42 strains of enterococci. The examination of antibiotic resistance/sensitivity profiles was performed by applying disk-diffusion procedure on Muller-Hinton agar. The number of enterococci determined in cheese samples depended on applied technological process. In the samples of fresh, by rennet coagulated cheese made from raw and cooked milk the number of enterococci was ranged from 8.0×10 4 to 9.0×10 6 cfu g-1 , and from 4.0×10 7 to 4.4×10 7 cfu g-1 , respectively. In the case of ripened cheeses made from raw and cooked milk subjected to acid coagulation the number of enterococci was ranged from <10 2 to 5.0×10 4 cfu g-1 and from 2.5×10 4 to 1.5×10 5 cfu g-1 , respectively. In the samples of fresh cheeses made from raw and cooked milk subjected to acid coagulation the number of enterococci was ranged from 2.4×10 5 to 2.12×10 7 cfu-g, and from 5×10 4 to 6×10 4 cfu g-1 , respectively. The phenotypic identification of isolated enterococcal strains was performed according to the following biochemical-physiological characteristics: microscopic examination (cell morphology), catalase activity, growth in MRS broth at 10 °C and 45 °C, growth at pH 9.6, growth in broth containing 6.5% NaCl, growth in 0.1% methylen blue milk, resistance at 60 °C/15 and 30 minute, Voges/Proskauer reaction, fermentation of ribose. The isolated strains of enterococci were resistant to following antibiotics: penicillin (65.82%), tetracycline (62.02%), lincomycin (68.35%), gentamycin (27.84%), neomycin (31.64%), erythromycin (31.64%) and chloramphenicol (65.82%).
Polyphasic characterization of Enterococcus strains isolated from traditional Moghan cheese in Iran
Journal of Food Safety, 2019
Traditional Moghan cheese is made from unpasteurized milk in the rural areas and nomadic tribes of Moghan region in Iran. In this study, we used a simple and rapid method for isolation of acid resistant lactic acid bacteria from traditional Moghan cheese. The six distinct isolates differentiated based on RAPD‐PCR were identified as members of Enterococcus faecium, E. faecalis, and E.durans species using classical phenotypic and biochemical tests as well as molecular methods. Based on the antibiotic susceptibility, the isolates were classified as resistant, intermediate, and sensitive. Cell‐free culture supernatants of isolates showed different antagonistic activity against the growth of some spoilage and food‐borne pathogens at two natural and neutralized pH conditions. Considering their tolerance to acid and bile, antagonistic effects on some spoilage and food‐borne pathogens and susceptibility to vancomycin, E. faecium strain ABRIINW.M (isolate IE2) and E. faecium strain ABRIINW.N...
European Food Research and Technology, 2012
Strong bacteriocins, or bacteriocins with a wide range of activity against pathogens and spoilage microorganisms, are actively sought for use as natural food preservatives. This work reports the inhibitory activity of 96 enterococcal isolates from two Iranian, raw milk cheeses against Wve indicator organisms (including Listeria innocua). Forty-eight isolates inhibited at least one indicator in spot agar assays. Of these, 20 isolates corresponding to 15 diVerent strains were shown to produce bacteriocinlike substances in liquid cultures. PCR analysis revealed the genes coding for enterocins (enterococcal bacteriocins) A, B, P or X, or their combinations, in all but one of these 15 strains. In addition, the gene coding for enterocin 31 was detected in two strains. No ampliWcation was obtained in one strain when using speciWc primers for all 13 bacteriocin genes sought. Three diVerent enterocin genes were identi-Wed in most strains and four in one strain. Although the concomitant production of bacteriocins is still to be veri-Wed, producers of multiple enterocins could be of great technological potential as protective cultures in the cheese industry.
Kocatepe veteriner dergisi, 2022
The objective of this research was to determine the presence of virulence genes (asa1, gelE, cylA, ace, esp, hyl and efaA), and vancomycin resistance genes (vanA, vanB, vanC2/C3) and the resistance to some antibiotics of Enterococcus spp. isolates previously identified from different stages of ripened white cheese production. In addition, gelatinase, β-hemolytic and DNase activity, and biofilm formations were examined phenotypically. In this study, efaA in 95.9%, asa1 in 89%, ace in 68.5%, esp in 52.1%, gelE in 78.1%, cylA in 16.4% and hyl in 23.3% of isolates were detected. Also, vanA in 31.5%, vanB in 8.2%, and in vanC2/C3 23.3% resistance genes were determined. β-hemolytic and DNase activity were detected in 23.2% and 16.4% of the isolates, while gelatinase activity and biofilm formation could not be detected phenotypically. Moreover, streptomycin and erythromycin resistances were found in 73.9% and in %43.8 of isolates. As a result, it was concluded that Enterococcus spp. may pose a risk for public health and food safety in terms of their virulence factors and antibiotic resistance. For this reason, it was suggested that the strains to be selected as starter cultures should be used after evaluating their virulence factors and resistance to antibiotics.
Journal of Food Protection, 2007
Enterococci account for an important fraction of the adventitious microflora of traditional cheeses manufactured in Mediterranean countries from small ruminants' raw milk and play an important role in the development of suitable organoleptic characteristics of the final product. It has been suggested that animals used for food or animals that supply edible products are a reservoir of antibiotic-resistant enterococci. The main purpose of this research effort was thus to identify, to the species level, a total of 73 enterococci with high tolerance to acidic pH and bile salts (as prevailing environmental conditions in the first portion of the gastrointestinal tract), which were previously isolated from the milk feedstock to the final product of Terrincho cheesemaking, and to determine their profiles of antibiotic susceptibility, coupled with the occurrence of specific virulence factors (especially in those that might eventually be claimed to exhibit suitable probiotic and technolog...
A collection of Enterococci spp. (about 96 isolates) were isolated from two Iranian raw milk cheeses, known as Lighvan and Koozeh cheeses and identified as Ent. faecium, Ent. faecalis, Ent. durans, Ent. casseliflavus and Ent. italicus by 16S rDNA sequencing. These 96 isolates were subjected to Agar-spot and well-diffusion assay in order to detect the bacteriocin-producing ability. According to Agar-spot method, only 48 isolates out of 96, showed bacteriocinproducing ability with clear-zone production on plates against indicator organisms. With well-diffusion Assay, these numbers decreased to 20 isolates which produced clear zone. Then, these 20 isolates (strains) were subjected to rep-PCR for typing and 15 distinct rep-PCR profiles (patterns) were identified.
Bacteriocin Production Of Enterococcus Species Isolated From Milk And Some Cheese Samples
Enterococci can be used as a starter or probiotic culture in the food industry. However, enterococci are also implicated in severe multi-resistant nosocomial infections. In this study, some probiotic characteristics such as antimicrobial activity and antibiotic susceptibility were investigated.Twenty-three strains of Enterococcus species isolated from Raw milk (7 strains), Karish cheese (8 strains), Domiati cheese (5 strains), and Ras cheese (3 strains) were studied for the capability to produce bacteriocin and antibiotic susceptibility.The seven studied antibiotics showed a different powerful effect on Enterococcus strains. The most effective antibiotic against 23 Enterococcus strains were amikacin, cefotaxime, and cefoxitin, which inhibited the growth of all tested strains, followed by levofloxacin azlocillin, and cloxacillin which inhibited 21, 19, and 19 strains, respectively, out of 23 studied strains. In addition, colistin showed the lowest powerful effect against all Enterococcus strains studied was resistant to this antibiotic. Antimicrobial activity was confirmed for all 23 strains against B. thuringiensis
Enterococcus lactis sp. nov., from Italian raw milk cheeses
INTERNATIONAL JOURNAL OF SYSTEMATIC AND EVOLUTIONARY MICROBIOLOGY, 2012
Ten atypical Enterococcus strains were isolated from Italian raw milk cheeses. The 16S rRNA gene, phenylalanyl-tRNA synthase alpha subunit (pheS), RNA polymerase alpha subunit (rpoA) and the 16S-23S rRNA intergenic transcribed spacer (ITS) sequences, randomly amplified polymorphic DNA (RAPD) PCR and the phenotypic properties revealed that the isolates represent a novel enterococcal species. On the basis of 16S rRNA gene sequence analysis, the isolates were closely related to Enterococcus hirae ATCC 8043 T , Enterococcus durans CECT 411 T and Enterococcus faecium ATCC 19434 T , with 98.8, 98.9 and 99.4 % sequence similarity, respectively. On the basis of sequence analysis of the housekeeping gene pheS, the reference strain, BT159 T , occupied a position separate from E. faecium LMG 16198. The group of isolates could be easily differentiated from recognized species of the genus Enterococcus by 16S-23S rRNA ITS analysis, RAPD-PCR and phenotypic characteristics. The name Enterococcus lactis sp. nov. is proposed, with BT159 T (5DSM 23655 T 5LMG 25958 T ) as the type strain.
International Journal of Food Microbiology, 2005
This study was undertaken to prepare tailor-made starter culture (TMSC) for Karst ewe's cheese production. Therefore, basic technological characteristics (growth ability in milk, acid production, and proteolytic activity) and antistaphylococcal potential were assessed for autochthonous enterococci and lactobacilli. Beside good growth in milk with numbers as high as 8 log CFU ml-1 , certain enterococci and lactobacilli also reduced pH below 5.0 and showed proteolytic activity. In antistaphylococcal testing, only pure strains of enterococci and lactobacilli were moderately antagonistic, but not in coagulated milks and coagulated milk extracts. Enterococci and lactobacilli with most relevant technological/antistaphylococcal properties were combined and tested as TMSC. In control (C) cheese-making, milk was inoculated with TMSC, while staphylococci (SC) cheese-making included contamination with staphylococci. In C trials, high logarithmic counts per g of cheese for enterococci (8.07-8.80) and lactobacilli (7.49-9.98) throughout the ripening period were found, and their authenticity was monitored by RAPD method. Furthermore, cheese extracts failed to inhibit pure cultures of staphylococci, while cheese pieces inhibited Staphylococcus sp. ST17. In SC trials, population dynamics of enterococci (7.81-9.04) and lactobacilli (7.98-9.63) corroborated the results in milk and in C trials, with staphylococci still present at the end of the ripening period but at lower counts than in fresh cheese.