In this study, prevalence, biotechnological and safety profiles of 588
isolates isolated from raw milk and Istrian cheese during different stages of ripening were analyzed. Despite the low and ...variable presence of enterococci in milk ((3.65±2.93) log CFU/mL), highly comparable enterococcal populations were established after 30 days of cheese ripening ((7.96±0.80) log CFU/g), confirming
spp. as a major part of the core microbiota of Istrian cheese. The dominant species were
(53.8%) and
(42.4%), while minor groups, consisting of
(2.84%) and
(0.95%), also occurred. A pronounced intraspecies variability was noticed based on molecular fingerprinting, with 35 strains (genotypes) detected. Most of the genotypes were farm-specific with one third being shared between the farms. This genotype variability reflected particular differences of Istrian cheese production, mainly variable salt concentration, ripening temperature and air humidity as well as microclimatic or vegetation conditions. There was considerable variation between the strains of the same species regarding wide range of biotechnologically important traits as well as their ability to survive in simulated gastrointestinal conditions. A considerable number of strains were resistant to critically important antibiotics such as tetracycline (43.56%), erythromycin (35.79%) and vancomycin (23.48%). Polymerase chain reaction-based detection did not identify any of the common genetic determinants for vancomycin and erythromycin resistance; for tetracycline
gene was detected. The presence of virulence genes including
and
was frequently recorded, especially among
strains.
As fermentation is an integral feature of both, dry sausage and cheese production, this has led to the evaluation of bacterial cultures
ssp.
(LL8307) and
(ED0207) originally isolated from artisanal ...Croatian hard type cheese to diversify the range of flavours of dry fermented sausages and to increase their microbiological safety. Both strains were chosen for their high or medium acidifying, proteolytic and/or lipolytic activity and bioprotective potential after step-by-step selection of wild isolates. Therefore, this study aims to evaluate the survival rate of selected starter cultures in wild boar meat sausages during the ripening period of 40 days at a local small-scale facility under artisanal conditions as well as their influence on sausage quality parameters.
Safety, biotechnological and probiotic properties of twenty-three enterococcal and lactococcal isolates of dairy origin were studied. Based on the results, two best candidates were selected and added to the meat batter during the artisanal wild boar meat sausage preparation where their survival rate, effect on physicochemical, microbiological and sensorial properties and histamine content were evaluated.
As revealed by repetitive element-polymerase chain reaction (rep-PCR), native starter cultures survived up to 15 days of ripening and were either absent from (LL8307) or reduced by 80% (ED0207) in final products. The application of native starter cultures rapidly decreased pH (p<0.05), leading to the significantly lower load of
coliforms and
in ready-to-eat sausages prepared by the addition of starter cultures (3.04-3.94 log CFU/g) than in the control (3.88-5.00 log CFU/g). Analysis of hedonic test data revealed that some of the sensory traits (odour, flavour, juiciness) of treatments with starter cultures were highly liked by the higher percentage of consumers. The results suggest that these starter cultures would represent a valuable tool to improve the homogeneity of artisanal manufacture and hygienic quality of fermented sausages and can be safely used for food application.
This is the first study to explore in depth the biotechnological potential of bacterial cultures isolated from artisanal Croatian cheese as functional starter cultures for high-quality game meat sausage production.
In this study, the influence of meat batter composition and sausage diameter on the development of microbiota and sensory traits of traditional, spontaneously fermented wild boar meat sausages are ...evaluated. This research also demonstrates how principal component analysis (PCA) can be used to relate product sensory properties to particular microbial genotype and to select potential starter or adjunct culture. Generally, similar microbiological results were obtained in all types of products. The undesirable microbiota was either not detected at any sausage production stage or its number decreased below the detection limit in ripened sausages. The low growth rate of lactic acid bacteria (LAB) was consistent with the obtained pH and slow acidification rate. Although no differences in the composition of LAB species were noticed between sausage types (50S=50% wild boar meat in small casing, 50L=50% wild boar meat in large casing, 100S=100% wild boar meat in small casing), a clear separation based on LAB genotypes could be observed. Upon quantitative descriptive analysis, significant differences in sensory attributes between sausage types were established. According to the PCA, the overall acceptability traits of sausages are closely linked to one
genotype (LM_4). Of all tested technological properties, LM_4 strains showed remarkable acidification ability, lowering the pH from pH=5.41 to 3.74, and pronounced proteolytic activity on skimmed milk as well as antagonistic activity against
(DSM 20231) and
(LMG 17208). Lipolytic and haemolytic activities were not detected, and all analyzed strains were susceptible to tested antibiotics and possessed no biogenic amine genes.
Bacterial communities associated with the ripening process in artisanal wild boar and deer meat sausages were investigated by molecular barcoding using the 16S rRNA gene as a marker. A core ...microbiota shared by 83.54% of the samples indicated remarkable level of Lactobacillus sakei and Lactobacillus curvatus, accounting for 20.55% in initial and 70.48% in final products as well as spoilage-associated bacteria including Stenotrophomonas, Bacillus, Pseudomonas, Carnobacterium and Brochothrix, with an average abundance 44.15% at the beginning and 13.98% at the end of the production. Of selected LAB isolates (n = 555), 43.83% were not suitable for food application due to the antibiotic resistance or the presence of the tdc gene. Most of the strains designated as safe were able to grow at 25 °C even in the presence of 3.0 and 6.0% of NaCl or pH 4.5, but exposure to the same stressors resulted in growth reduction at 12 °C. Acidification and antimicrobial activity were found in 65.62% and 37.50% of strains, respectively. Most of the strains showed lipolytic and proteolytic activity, but only 9.37% were able to degrade sarcoplasmic proteins. These results give important information for the development of new starter formulation for the production of high quality game meat sausages.
•The microbiota of spontaneously fermented game meat sausages was very complex.•644 unique OTUs were detected by high-throughput 16S rRNA Illumina sequencing.•Domination of Lactobacillus spp. and high count of meat spoilage bacteria.•Considerable variation regarding the safety and technological properties of LAB strains.•Only 17.5% of tested LAB could be considered as starter or bioprotective cultures.
Pozadina istraživanja. S obzirom na to da se fermentacija podjednako koristi za dobivanje trajnih kobasica i tvrdih sireva, bakterijske kulture Lactococcus lactis ssp. cremoris (LL8307) i ...Enterococcus durans (ED0207) izolirane su iz tradicionalnih hrvatskih tvrdih sireva, te detaljno okarakterizirane radi postizanja palete okusa trajnih fermentiranih kobasica i povećanja njihove mikrobiološke sigurnosti. Oba soja su odabrana nakon postupne selekcije autohtonih izolata zbog njihove velike ili srednje velike sposobnosti zakiseljavanja, proteolitičke i/ili lipolitičke aktivnosti, te moguće biozaštitne uloge. Stoga je svrha ovog istraživanja bila procijeniti stopu preživljavanja odabranih starter kultura u kobasicama od mesa divlje svinje tijekom perioda zrenja od 40 dana pri tradicionalnim uvjetima proizvodnje, te ispitati njihov utjecaj na parametre kakvoće kobasica. Eksperimentalni pristup. Ispitana su sigurnosna, biotehnološka i probiotička svojstva dvadeset i triju izolata enterokoka i laktokoka podrijetlom iz hrvatskih tradicionalnih tvrdih sireva. Na osnovi dobivenih rezultata izabrana su dva najbolja kandidata, koja su dodana nadjevu kobasica od mesa divlje svinje, te je procijenjena stopa preživljavanja izolata, njihov utjecaj na fizikalno-kemijska, mikrobiološka i senzorska svojstva kobasica te udjel histamina. Rezultati i zaključci. Analizom ponavljajućih elemenata lančane reakcije polimerazom (rep-PCR) utvrđeno je da su autohtone starter kulture preživjele u kobasicama do 15 dana zrenja, a da ih nije bilo (soj LL8307) ili je njihov broj bio reduciran za 80 % (soj ED0207) u gotovim proizvodima. Primjena odabranih starter kultura brzo je smanjila pH-vrijednost kobasica (p
Istrian ewe’s milk cheese is an autochthonous product that is manufactured for generations on small family farms in the Croatian peninsula Istria. Traditional Istrian cheese is made from ...unpasteurized ewe’s milk, without the addition of starter cultures. Consequently, the specific flavour and texture of the Istrian cheese is owed to metabolic processes of indigenous microflora of which Lactobacillus species play pivotal role. Characterisation and selection of indigenous lactobacilli may result in the potential use of selected strains as starter, bioprotective or even probiotic cultures. This study focuses on potential use of Lactobacillus plantarum and Lactobacillus casei isolated from traditional Istrian cheese as starter cultures, by using methods that determine their proteolytic, lipolytic, antimicrobial and haemolytic potential, as well as their ability of acidification, autoaggregation and survival in simulated gastrointestinal conditions. Our results indicated that from 12 representative strains most revealed a low or moderate proteolytic activity as well as absence of lipolytic and haemolytic activities. From 12 strains, 5 of them showed a medium to strong acidification ability and lowered the pH of milk below 5.00 after 24 hours of incubation. Furthermore, almost all isolates exhibited antimicrobial activity against Serratia marcescens, and lowest number of isolates showed antimicrobial activity against Staphylococcus aureus and Listeria innocua. The studied Lactobacillus strains revealed high survival rate in a simulated oral cavity and duodenum conditions, while the survival ability in a simulated gastric conditions was much lower. Ability to aggregate was low for all tested strains, after 3 hours and after 5 hours of incubation.
Spontaneously fermented wild boar and deer meat sausages produced in Croatia were physicochemically and microbiologically investigated at different time points of their production. Final products ...resulted with pH and aw values between 5.04–5.53 and 0.83–0.87, respectively. The histamine concentration was below 5.0 mg/kg whereas tyramine content ranged from 47.3 to 219.0 mg/kg. A total of 917 isolated lactic acid bacteria (LAB) were genotyped by rep-PCR and identified by 16S rRNA gene sequencing. Overall, Leuconostoc mesenteroides was identified as the most frequently isolated species (n = 259), followed by Lactobacillus sakei (n = 190) and Enterococcus casseliflavus (n = 106). Cluster analysis revealed a remarkable intraspecies diversity and a strong sausage-specific clustering of the LAB genotypes, indicating meat as a probable source of microbial diversity in sausages. 14.38% of LAB were positive for tyramine encoding gene and no other target biogenic amines genes were detected. Due to the elevated number of presumptive pathogens (E. coli. Enterobacteriaceae, B. cereus group, coliforms) in ready-to-eat sausages, 33.33% of products can be considered as inappropriate for human consumption.
•Le. mesenteroides and Lb. sakei were dominant species in artisan game meat sausages.•High intraspecies diversity and strong sausage-specific clustering of the LAB genotypes.•No histamine and elevated tyramine concentration measured in final products.•Only tyramine encoding gene and no other biogenic amines genes were detected.•High counts of presumptive pathogens in 33.33% of ready-to-eat sausages.
Stabilna crijevna mikrobiota utječe na mnogo načina na održavanje ili poboljšanje zdravlja svinja. Dosadašnja istraživanja su pokazala pozitivan utjecaj crijevne mikrobiote u iskoristivosti hranjivih ...tvari, poboljšanju morfoloških i fizioloških svojstava gastrointestinalnog (GI) trakta, u sprječavanju prodora patogenih vrsta, a također mikroorganizmi probavila imaju važnu imunološku ulogu. Osim korisnih i poželjnih bakterijskih vrsta, crijevna mikrobiota svinja može uključivati patogene poput
Salmonella
spp.,
Clostridia
spp. i patogenih sojeva E. coli. U slučaju narušene ravnoteže prirodno prisutnih mikrobnih zajednica, ovi patogeni mogu uzrokovati bolesti svinja te posljedično gubitke u proizvodnji. U prošlosti su za osiguranje stabilne mikrobiote GI trakta preventivno korišteni antibiotici, no od kada je prepoznata štetnost takve prakse sve više se koriste probiotici, prebiotici te različiti aditivi. Za takav pristup, potrebno je poznavati sastav i brojnost mikrobnih zajednica prisutnih u GI traktu svinja kao i identificirati ključne mikroorganizme u prevenciji infekcija i održavanju zdravlja domaćina. Zbog toga je u fokusu znanstvenog interesa definirati i detaljno karakterizirati crijevnu mikrobiotu zdravih jedinki, istražiti međusobne mikrobne interakcije, kao i interakcije s domaćinom, te različite načine osiguravanja stabilne crijevne mikrobiote kako bi se održala vitalnost i zdravlje životinja.
Stable gut microbiota may influence the health and wellbeing of pigs. Results of up-to-date studies have shown a positive effect of gut microbiota on feed efficiency, improvement of morphological and physiological characteristics of gastrointestinal (GI) tract, prevention of breach of pathogenic species, as well as a positive role in immunology. However, besides beneficial bacterial species, gut microbiota of pigs can include pathogens such as Salmonella spp., Clostridia spp. and pathogenic strains of E. coli. When the balance of naturally present microbial communities is disturbed, these pathogens can cause illness of pigs, causing production losses. Antibiotics were used in the past for ensuring a stable gut microbiota, but since damaging effects of such practice were recognized, alternative methods have been considered, such as the use of probiotics and prebiotics. For this approach, it is necessary to know the composition and abundance of microbial communities in GI tract of healthy pigs, as well as to identify the most important microorganisms that have a role in the prevention of infection and maintaining the wellbeing of the host. Therefore, many studies have been focused on defining and detailed characterization of gut microbiota of healthy individuals, to study interactions between microbes as well as microbial interactions with the host. Also, different approaches have been considered to ensure a stable gut microbiota to maintain vitality and health of animals.
Arbuskularna mikoriza je simbiozni odnos pri kojem gljiva prodire u stanice korteksa korijena vaskularne biljke. Selekcija prikladnog soja gljiva, koja ovisi o uzgajanoj kulturi, jedan je od ...najvažnijih faktora za ostvarivanje uspješne arbuskularne mikorize. Jednom kada se ostvari uspješan simbiozni odnos, koji na određeni način predstavlja most između korijena biljke i tla, dolazi do pozitivnog utjecaja na prinos kao i na kvalitetu maslinova ulja. Dosadašnja istraživanja su potvrdila kako arbuskularna mikoriza može pozitivno utjecati na ishranjenost i poboljšano zdravstveno stanje masline, prinos plodova kao i na kemijski sastav maslinovog ulja. Ovakva saznanja omogućuju poboljšanje te moduliranje različitih parametara proizvodnje u maslinarstvu.
U ovom radu istražen je utjecaj sastava mesnog nadjeva i promjera kobasica na razvoj mikrobiote i senzornih osobina tradicijskih, spontano fermentiranih kobasica od mesa divlje svinje. Ovo ...istraživanje pokazuje kako se analizom glavnih komponenata mogu povezati senzorna svojstva proizvoda s određenim sojem bakterija, te za selekciju potencijalnih starter kultura. Općenito govoreći, nakon mikrobioloških analiza svih vrsta proizvedenih kobasica dobiveni su slični rezultati. Niti u jednoj fazi proizvodnje kobasica nije detektirana neželjena mikrobiota ili je njezin broj u zrelim kobasicama bio ispod granice detekcije. Niska stopa rasta bakterija mliječne kiseline bila je u skladu s dobivenim pH-vrijednostima i sporom stopom zakiseljavanja. Iako nisu uočene razlike u sastavu vrsta bakterija mliječne kiseline između različitih tipova kobasica (50S=50 % mesa divlje svinje u tankom ovitku, 50L=50 % mesa divlje svinje u debelom ovitku, 100S= 100 % mesa divlje svinje u tankom ovitku), moglo se opaziti jasno odvajanje na osnovi genotipova pojedinih bakterija. Kvantitativnom opisnom analizom utvrđene su bitne razlike u senzornim značajkama različitih vrsta kobasica. Prema analizi glavnih komponenata, svojstva dopadljivosti kobasica usko su povezana s jednim genotipom Leuconostoc mesenteroides (LM_4). Od svih ispitanih tehnoloških svojstava, sojevi LM_4 pokazali su izuzetnu sposobnost zakiseljavanja, snižavajući pH-vrijednost s 5,41 na 3,74, te izrazito proteolitičko djelovanje u obranom mlijeku, te antagonističku aktivnost prema bakterijama Staphylococcus aureus (DSM 20231) i Brochothrix thermosphacta (LMG 17208). Lipolitička i hemolitička aktivnost nije detektirana, a svi analizirani sojevi bili su osjetljivi na testirane antibiotike i nisu posjedovali gene za biogene amine.
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