1,721,083 research outputs found
Review of microbiological, chemical and molecular method for determining the food safety
No full textKonvencionalne mikrobiološke metode za detekciju patogena su dugotrajne. Postoje i mnoge brže metode, međutim konvencionalne mikrobiološke metode za ispitivanje zdravstvene sigurnosti hrane još uvijek ostaju službena korištena metoda. Svrha ovog rada bila je usporediti mikrobiološke, molekularne i biokemijske metode u određivanju patogenih mikroorganizama iz uzoraka kravljeg, ovčjeg i kozjeg mlijeka. Od ukupno 15 analiziranih uzoraka namirnica životinjskog podrijetla 73,3 % uzoraka su bili pozitivni na Listeria vrste na PALCAM agaru, a u samo 13,3 % uzoraka API- Listeria testom je potvrđena L. monocytogenes. Od 100 % uzoraka pozitivnih na stafilokoke na Baird-Parker agaru, API Staph testom u 26,6 % uzoraka potvrđena je Staphylococcus aureus. Bakterija iz roda Salmonella sp. dokazana je API 20 E testom u 9 od 15 uzoraka (3 kravlja, 3 ovčje i 3 kozja).Conventional microbiological methods for detection of pathogens are longlasting. There are many faster methods, however, conventional microbiological methods for testing food safety are still remain the official method that are used. The purpose of this study was to compare the microbiological, biochemical and molecular methods for the determination of pathogenic microorganisms from samples of cow's, sheep's and goat's milk. Out of 15 analyzed samples of foods of animal origin, 73.3% of samples were positive for Listeria species at the palm of agar, while only 13.3% of samples of API-Listeria test confirmed L. monocytogenes. 100% of samples positive staphylococci on Baird-Parker agar, API Staph test in 26.6% of the samples was confirmed by Staphylococcus aureus. Bacteria of the genus Salmonella sp. proved by the API 20 E test in 9 out of 15 samples (3 cows, 3 sheep and 3 goat)
Formulation and development of a multi-layered, microencapsulated probiotic with targeted health effects
No full textU ovom radu provedena je izolacija bakterija mliječne kiseline iz mlijeka magarice i kobile, stolice zdravog dojenčeta te je formirana baza izolata kojima je pridodan soj prethodno izoliran iz fermentirane sirutke. Bakterijski sojevi identificirani su i podvrgnuti sustavnoj probiotičkoj karakterizaciji kako bi se izdvojili sojevi s potencijalom u zaštiti zuba i usne šupljine, inhibicijom Helicobacter pylori, protuupalnom i antioksidativnom aktivnošću. Bakterijski izolati iz mlijeka magarice i kobile pokazali su značajnu inhibiciju i koagregaciju s uzročnicima karijesa, gingivitisa i parodontitisa te izraženu protuupalnu aktivnost blokirajući upalnu signalizaciju ljudskih mononuklearnih stanica i proizvodnju proupalnog citokina TNF-α u uvjetima upale. Izolati iz stolice dojenčeta pokazali su inhibitorni potencijal prema patogenoj bakteriji H. pylori dok je Lactobacillus plantarum S1, izoliran iz sirutke, pokazao sposobnost smanjenja oksidativnog stresa u okolini djelujući protektivno na DNA ljudskih mononuklearnih stanica u uvjetima oksidativnog stresa. Navedeni izolati uklopljeni su u višeslojni mikroinkapsulat koji je razvijen korištenjem dvaju neškodljivih polimera alginata i kitozana te je razvijena troslojna kapsula formirana tako da na ciljanom mjestu otpušta sojeve čija je aktivnost potrebna u ustima, želudcu i crijevima.In this study, lactic acid bacteria were isolated from donkey and mare milks and from the feces of a healthy infant, and a base of isolates was formed to which a strain previously isolated from fermented whey was added. The bacterial strains were identified and subjected to systematic probiotic characterization in order to detect the strains with the potential for dental and oral protection, Helicobacter pylori inhibition, anti-inflammatory and antioxidant activities. Bacterial isolates from donkey and mare milk showed significant inhibition and coaggregation with pathogens associated with caries, gingivitis, and periodontitis, and exhibited high anti-inflammatory activity by blocking inflammatory signaling of human mononuclear cells and the production of proinflammatory cytokine TNF-α under inflammatory conditions. The isolates from infant feces showed inhibitory potential against the pathogenic bacterium H. pylori, while Lactobacillus plantarum S1 isolated from whey showed the ability to reduce oxidative stress in the environment by protecting the DNA of human mononuclear cells under oxidative stress. These isolates were incorporated into a multilayer microcapsule developed using two innocuous polymers (alginate and chitosan). This resulted in a three-layer capsule that releases the strains at the target site, whose activity is required in the mouth, stomach, and intestine
Survival of the dominant microflora of horsemeat sausage in the intestinal tract of the mice
No full textU ovom je radu istražena adhezija bakterijskoj soja Lactococcus lactis ssp. lactis 5K1 izoliranog iz konjske kobasice na tanko i debelo crijevo miša u in vitro i in vivo uvjetima, te negova sposobnost da preživi uvjete u intestinalnom traktu. Budući da je u preliminarnim istraživanjima Lactococcus lactis ssp. lactis 5K1 pokazao značajnu inhibiciju rasta prema patogenim mikroorganizmima iz hrane, proizveo značajnu količinu mliječne kiseline (17,23 g/L) te zadovoljio osnovne kriterije za selekciju probiotičkog soja u in vitro uvjetima, provedena su in vivo istraživanja na pokusnim miševima. Lactococcus lactis ssp. lactis 5K1 preživljava uvjete u intestinalnom traktu te znatno smanjuje broj bakterijskih stanica Salmonella sp. u miševa inficiranih sa bakterijom Salmonella sp. Lactococcus lactis ssp. lactis 5K1 je pokazao osnovne funkcionalne kriterije za izbor probiotičkih sojeva, te se kao takav može upotrijebiti kao funkcionalna autohtona starter kultura za fermentirane mesne proizvode.The aim of this work was to investigate adhesion ability of bacterial strain Lactococcus lactis ssp. lactis 5K1, isolated from "horse meat saussages", on the small and large intestine of mice in vitro and in vivo conditions also his ability to survive conditions in the intestinal tract. Considering that in preliminary investigation L. plantarum 1K has shown good antimicrobial activity against pathogen microorganisma from food, has produced significant amount of lactic acid (17,23 g/L)and satisfied the basic criteria for selection of probiotic strains in vitro conditions, in vivo studies in experimental mice were carried out. Lactococcus lactis ssp. lactis 5K1 survive the conditions in the intestinal tract and significantly reduced the number of bacterial cells of Salmonella sp. in mice infected with bacterium Salmonella sp. Considering that Lactococcus lactis ssp. lactis 5K1 has demonstrated the basic functional criteria for the selection of probiotic strains, as such, it can be used as functional autochthonous starter culture for fermented meat products
Antimicrobial activity of natural microbial populatios in cheese from Krk
No full textSvrha ovog rada bila je izolirati autohtonu mikrobnu populaciju iz uzoraka krčkog sira proizvedenih na obiteljskom poljoprivrednom gospodarstvu (OPG) otoka Krka. Provedena je izolacija i identifikacija autohtone mikrobne populacije u krčkom siru. Korištenjem klasičnih mikrobioloških i biokemijskih metoda identifikacije ustanovljena je prisutnost slijedećih bakterijskih vrsta: Lactobacillus brevis i Pediococcus acidilactici. Ovi bakterijski izolati pokazali su antimikrobnu aktivnost prema test mikroorganizmima (Salmonella sp., Lysteria monocytogenes, Staphylococcus aureus i Escherichia coli), najčešćim konataminantima u hrani.The purpose of this study was to isolate the indigenous microbial population samples from cheese produced on the family farm from Krk. Isolation and identification of indigenous microbial population in mentioned products were performed. Used classical microbiological and biochemical methods of identification established presence of following bacterial species Lactobacillus brevis i Pediococcus acidilacticii. These strains have shown antimicrobial activity against test microorganisms (Salmonella sp., L. monocytogenes, S. aureus and E. coli), most common contaminants in food
Antimicrobial activity of sage and thyme extracts on the growth of pathogenic microorganisms
No full textPatogeni mikroorganizmi mogu se naći u različitim vrstama hrane pa korištenje prirodnih antimikrobnih supstanci, poput eteričnih ulja aromatičnih biljaka, može biti važno u očuvanju kvalitete različitih namirnica. Cilj rada bio je ispitati količinu ukupnih fenola, flavonoida i antimikrobnu aktivnost ekstrakata kadulje (Salvia officinalis L.) i majčine dušice (Thymus serpyllum L.), ubranih na različitim geografskim područjima Republike Hrvatske (Pag, Brač, Pirovac) prema odabranim test mikroorganizmima: Escherichia coli, Staphylococcus aureus, Salmonella spp. i Listeria monocytogenes. Određivanje ukupnih fenola temelji se na kolornoj reakciji koja je posljedica reakcije fenola s Folin–Ciocalteu-ovim reagensom, a intenzitet nastalog obojenja mjeren je spektrofotometrijski. Određivanje flavonoida temelji se na njihovom svojstvu da s aluminijevim kloridom tvore kompleks, a intenzitet obojenja proporcionalan je količini prisutnih flavonoida. Antimikrobni učinak i stupanj inhibicije određivani su turbidimetrijskom metodom. Dobiveni rezultati pokazuju da ekstrakti kadulje sadrže veću koncentraciju flavonoida i ukupnih fenola od ekstrakata majčine dušice. Ujedno, postoji značajna razlika između koncentracija fenola u ekstraktima iste biljke ovisno o mjestu sabiranja. Ekstrakti pokazuju antimikrobno djelovanje na rast ispitivanih bakterija.Pathogenic microorganisms can be find in different types of food so usage of antimicrobial supstances as essential oils of aromatic drugs can be very important in preserving the quality of different foods.The aim of this study was to examine the amount of total phenols, flavonoids and the antimicrobial activity of sage (Salvia officinalis L.) and thyme (Thymus serpyllum L.) extracts collected from different geographic regions of Croatia (Pag, Brač, Pirovac) against selected bacteria: Escherichia coli, Staphylococcus aureus, Salmonella spp. and Listeria monocytogenes. Determination of total phenols is based on color vision feedback, which is the result of reaction of phenol with Folin-Ciocalteu's reagent, and the staining intensity was measured using the spectrophotometric method. Determination of flavonoids is based on their property to form a complex with aluminum chloride and the resulting color is proportional to the amount of flavonoids present. Antimicrobial effect and the degree of inhibition were determinated by turbidimetric method. The results showed that the sage extracts contain larger amount of flavonoids and total phenols than the thyme extracts. Also, there is a significant difference between phenol concentration in extracts of the same drug depending on a geographic place of collecting. Extracts show antimicrobial activity to growth of selected bacteria
Development of a lyophilized probiotic microencapsulate with the addition of L-ascorbic acid
No full textDo danas su dokumentirani višestruki korisni učinci probiotika na zdravlje domaćina. Iako je tržište preplavljeno probiotičkim proizvodima, nerijetko provedene studije pokazuju da dostupni probiotički sojevi ne zadovoljavaju osnovne probiotičke kriterije. Jedan od glavnih kriterija je visoki stupanj preživljavanja tijekom prolaska kroz gastrointestinalni sustav domaćina kako bi se na ciljanom mjestu ispoljili korisni učinci. S obzirom na to da je nužno da probiotici u što većem broju prežive navedene stresne uvjete, često se koriste tehnike koje štite stanice netoksičnim biopolimerima. Primjer primjene takvog matriksa je mikroinkapsulacija u alginatnom nosaču. Uz navedeno, važno je da se pripravljenim proizvodima maksimalno produlji trajnost pa se koriste tehnike liofilizacije koje omogućavaju dulje skladištenje. Uz osnovne probiotičke karakteristike često su poželjne i određene funkcionalne karakteristike. Primjerice, novija istraživanja potiču konzumaciju proizvoda s visokim antioksidacijskim potencijalom zbog mnogobrojnih korisnih učinaka na zdravlje. U ovom radu, korištenjem tehnika mikroinkapsulacije i liofilizacije odabran je najefikasniji način zaštite odabranih probiotičkih bakterija: Lactobacillus plantarum M2 i Lactobacillus plantarum KO9. Liofilizirani mikroinkapsulati navedenih sojeva pokazali su visok stupanj preživljavanja u simuliranim uvjetima gastrointestinalnog sustava i bili su prikladan nosač L-askorbinske kiseline povećavajući antioksidativni kapacitet pripravka. Određena je bazalna antioksidacijska aktivnost odabranih sojeva bakterija mliječne kiseline izražena kao sposobnost uklanjanja 2,2-difenil-1-pikrilhidrazil (DPPH) radikala. Budući da L-askorbinska kiselina iskazuje potencijalnu antimikrobnu aktivnost, istražen je utjecaj na rast odabranih patogenih bakterija: Salmonella enterica serovar Typhimurium ATCC 27853 , Escherichia coli ATCC 25922, Staphylococcus aureus ATCC 25923 i Listeria monocytogenes ATCC 2356 te je koncentracija od 50 mg mL-1 značajno inhibirala rast navedenih patogena.Multiple beneficial effects of probiotics on hosts health have been documented. Although the market is flooded with probiotic products, studies often show that available probiotic strains do not fulfill probiotic requirements. One of the main criteria is a high survival rate during passage through the hosts gastrointestinal system in order to exert beneficial effects at the target site. Since it is necessary for probiotics to survive these stressful conditions, techniques that protect cells with non-toxic biopolymers are often used. An example of the use of such a matrix is microencapsulation in an alginate carrier. In addition to the above, it is important to extend shelf life, so lyophilization techniques are used in order to enable longer storage. In addition to the basic probiotic characteristics, certain functional characteristics are often desirable. For example, recent studies encourage the consumption of products with high antioxidant potential due to the many beneficial health effects. In this paper, using the techniques of microencapsulation and lyophilization, the most effective way of protection of selected probiotic bacteria was selected: Lactobacillus plantarum M2 and Lactobacillus plantarum KO9. Lyophilized microencapsules of these strains showed a high survival rate in simulated conditions of the gastrointestinal system and were a suitable carrier of L-ascorbic acid increasing the antioxidant capacity of the composition. The basal antioxidant activity of selected strains of lactic acid bacteria expressed as the ability to remove 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals was determined. Since L-ascorbic acid exhibits potential antimicrobial activity, the influence on the growth of selected pathogenic bacteria: Salmonella enterica serovar Typhimurium ATCC 27853, Escherichia coli ATCC 25922, Staphylococcus aureus ATCC 25923 and Listeria monocytogenes ATCC 2356 was investigated and the concentration of 50 mg mL-1 significantly inhibited the growth of these pathogens
Microbiological quality of lamb sack (mišina) and cheese ripened in lamb sack
No full textSir iz mišine autohtoni je mliječni proizvod koji se tradicionalno proizvodi na obiteljskim gospodarstvima Dalmatinske zagore. Mišina je ovčja ili janjeća koţa u kojoj sir zrije. Mnogi mikroorganizmi induciraju promjene u okusu, nutritivnoj kvaliteti, teksturi, aromi i sigurnosti samog proizvoda. Stoga je cilj ovog rada bio odrediti mikrobiološku kakvoću te istražiti prirodnu, autohtonu mikrobnu populaciju mišine i sira iz mišine tijekom različitih faza zrenja kako bi se utvrdilo koje skupine mikroorganizama imaju potencijal uporabe kao funkcionalne starter kulture. Analiza je provedena na uzorcima mlijeka, sirutke, gruša, ovčje mišine te kravljeg i ovčjeg sira iz mišine, a upotrijebljene su klasične mikrobiološke metode i biokemijske (API) metode. Izolirani autohtoni bakterijski izolati pripadali su bakterijskim rodovima Lactobacillus i Staphylococcus. Dobiveni rezultati upućuju na mogućnost korištenja izoliranih bakterijskih sojeva kao potencijalnih starter kultura. Sir iz mišine proizvodi se iz toplinski neobrađenog mlijeka i rezultati ukazuju da mikrobiološka kvaliteta sirovina za proizvodnju nije zadovoljavajuća. Ipak, u gotovom proizvodu (sir) više nije bilo za zdravlje potencijalno nepogodnih mikrobnih kultura.Cheese ripened in lamb sack (mišina) is indigenous dairy product traditionally produced on family farms in the Dalmatia. Lamb sack is sheep or lambs skin in which cheese ripens. Many microorganisms induce changes in taste, nutritional quality, texture, flavor and safety of the product itself. The purpose of this study was to determine the microbiological quality and explore the natural, indigenous microbial population of lamb sack and cheese from lamb sack during different stages of ripening to determine which groups of microorganisms have potential use as functional starter cultures. The analysis was performed on samples of milk, whey, curd, lamb sack, and cow’s and sheep's cheese from lamb sack. Classical microbiological methods and biochemical (API) method were used. Isolated indigenous bacterial isolates belonged to the bacterial genera Lactobacillus and Staphylococcu.. These results indicate the possibility of using isolated bacterial strains as potential starter cultures. Cheese from lamb sack is produced from raw milk and the results indicate that the microbiological quality of raw material for production is not satisfactory. However, in the final product (cheese) there was no longer any to the health potentially unfavorable microbial cultures
Antimicrobial effect of essential oils pine needles and cones
No full textEterična ulja sastavni su dio aromatskih i ljekovitih biljaka. Mnoga istraživanja potvrdila su snažno antimikrobno djelovanje eteričnih ulja, te kao takva imaju široku mogućnost primjene u prehrambenoj industriji kao prirodni biokonzervansi, te u farmaceutskoj industriji. Stoga je cilj ovog rada utvrditi da li eterična ulja borovih iglica i češera s područja Gorskog kotara posjeduju antimikrobno djelovanje na rast odabranih sojeva mikroorganizama (S. aureus, E. coli, Salmonella sp., L. monocytogenes, C. albicans), potencijalnih ljudskih i životinjskih patogena. Dobiveni rezultati su pokazali da eterična ulja borovih iglica i češera imaju neznatno inhibicijsko djelovanje na rast odabranih test mikroorganizama.Essential oils are an integral part of aromatic and medicinal plants. Many studies have confirmed the strong antimicrobial activity of essential oils, and as such have extensive use in the food industry as natural biopreservatives, and the pharmaceutical industry. The aim of this study was to determine whether the essential oil of pine needles and pinecones from Gorski Kotar have an antimicrobial effect on the growth of selected strains of microorganisms (S. aureus, E. coli, Salmonella sp., L. monocytogenes., C. albicans), the potential human and animal pathogens. The results showed that essential oil of pine needles and pinecones have a slightly inhibitory effect on growth of selected test organisms
A microbiological analysis of the activated sludge from the wastewater purifier in a winery
No full textMikrobna populacija aktivnog mulja otpadnih voda je kompleksan mikrobni ekosustav. Stoga je cilj rada odrediti sastav mikrobne populacije u uzorcima aktivnog mulja iz otpadne vode vinarije iz Istre. Rezultati istraživanja dobiveni su mikrobiološkom analizom aktivnog mulja iz otpadne vode vinarije tijekom 3 mjeseca. Analize su provođene u više intervala ovisno o tome kako su uzorci pristizali na analizu. Izvršena je analiza 12 pristiglih uzoraka u rasponu od 87 dana. U svim uzorcima aktivnog mulja izolirani su mikroorganizmi karakteristični za otpadne vode i to: protozoe, nematode, bakterije te kvasci, a uzevši u obzir da se radi o prihvatnom tanku vinarije u koji se osim otpadne vode iz proizvodnog pogona vinarije ulijevaju i kanalizacijski ispusti, bilo je za očekivati prisutnost koliformnih bakterija, što je analizama i potvrđeno.A microbial population in the activated sludge from wastewaters is a complex microbial ecosystem. Therefore, the goal of this work was to determine the composition of the microbial population in the samples of wastewater from the winery in Istria. The results were obtained based on the measurements performed in a 3-month period. Analyses were conducted in several time intervals, depending on how the samples had arrived for analysis. There were 12 samples over the course of 87 days. All samples of activated sludge contained the characteristic organisms: protozoa, nematodes, bacteria, and yeasts. Considering the samples were taken from a tank that also takes in sewage, the presence of coliform bacteria was expected, which was confirmed by analyses
Isolation of indigenous microbial populations in slavonski kulen
No full textSvrha ovog rada bila je izolirati autohtonu mikrobnu populaciju iz uzoraka slavonskih kulena proizvedenih na tradicionalan način u seoskim domaćinstvima. Autohtona mikrobna populacija izvor je sojeva za razvoj starter kultura koje će, između ostalog, utjecati na aromu i teksturu određenog tradicionalnog mesnog proizvoda. Dominantna mikrobna populacija sastojala se od bakterija mliječne kiseline (BMK) i to : Lactobacillus plantarum u dva uzorka, Lactobacillus delbrueckii u dva uzorka, te Leuconostoc mesenteroides i Lactobacillus acidophilus u po jednom uzorku kulena. Također, su prevladavale i bakterije iz roda Staphylococcus, tipični predstavnici starter kultura za meso, i to: S. xylosus, S. warneri, S. lentus i S. auricularis.The purpose of this study was to isolate the indigenous microbial population of samples from the Slavonian kulen produced in the traditional way in rural households. Autochthonous microbial population are potential source of starter cultures, which can be used to obtain top quality flavour and texture for specific traditional meat products. Dominant microbial populations consists of lactic acid bacteria (LAB): L. plantarum, in two samples, L. delbrueckii, in two samples, L. mesenteroides, and L. acidophilus in one sample of Slavonian kulen. The bacteria from the genus of Staphylococcus were also dominated in microbial population in Slavonian kulen, which are also the ingrediens of starter cultures for meat, such as follows: S. xylosus, S. warneri, S. lentus and S. auricularis
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