Czech Journal of Food Sciences, 2011 (vol. 29), Special Issue
Antimicrobial factors effects on biofilm formation in Staphylococcus aureus
Sabina Purkrtová, Jana Babulíková, Renáta Karpíšková, Kateřina Demnerová, Jarmila Pazlarová
Czech J. Food Sci., 2011, 29(10):S1-S10 | DOI: 10.17221/319/2011-CJFS 
We determined the disinfectant effects of benzalkonium chloride (BC) and Savo (SV), a chlorine compound, on the biofilm and planktonic cells in 23 strains S. aureus mainly food isolates. The biofilm formation was performed in a model system using microtiter polystyrene plates COSTAR 3797 in trypton-soy broth with 1% glucose at 30°C. Benzalkonium chloride (BC) at 125 mg/l, applied directly on 24 h old biofilm, was able to remove the biofilm matrix in 21 strains, and to stop the reproduction of the biofilm cells in 23 strains. BC at the concentration of 125 mg/l was lethal to planktonic cells, coincubated for 24 h or treated...
Genetic determinants of mycotoxin synthesis in genus Fusarium
Hana Havránková, Jarmila Pazlarová, Jaroslava Ovesná
Czech J. Food Sci., 2011, 29(10):S86-S93 | DOI: 10.17221/314/2011-CJFS
The fungi of the genus Fusarium occur worldwide mainly on cereal grains. They are considered to be not only plant-pathogenic, but also the producers of secondary metabolites - mycotoxins. In our study, we focused on the analysis by Q-PCR of two genes expression - Tri4, Tri10 - involved in the production of Fusarium mycotoxin deoxynivalenol. Reference genes β-tub and UBC were found to be suitable for the expression level normalisation using the program geNorm. The level of expression of the target genes was analysed on four isolates of Fusarium graminearum grown in vitro....
Comparison of methods for isolating fungal DNA
Petra MOŤKOVÁ, Jarmila VYTŘASOVÁ
Czech J. Food Sci., 2011, 29(10):S76-S85 | DOI: 10.17221/266/2011-CJFS
In this study methods of fungal DNA isolation were optimised and compared. The aim of the isolation processes was to obtain DNA of sufficient quality and quantity necessary for its amplification, as most detection techniques require DNA amplification before the proper DNA detection itself. For this purpose, classic methods of DNA extraction were compared and optimised while isolations using commercial kits were also done. The methods were evaluated from several perspectives, with focus especially laid on the isolated DNA not contain PCR inhibitors which would prevent DNA amplification, thus inhibiting the detection itself. For optimising the individual...
Effect of selected fungicides on the Fusarium growth and toxins production
Dana Hrubošová-Hrmová, Jarmila Vytřasová, Petra Moťková
Czech J. Food Sci., 2011, 29(10):S69-S75 | DOI: 10.17221/268/2011-CJFS
We examine the effects of selected fungicides on the Fusarium growth and toxins production especially of DON and T-2 toxins. Appropriate nutritive media were prepared containing different concentrations of the fungicides tested (Horizon 250 EW and Falcon 460 EC), inoculated with Fusarium moulds, and incubated under various conditions. The extraction of Fusarium toxins and their determination were carried out after the incubation using Agra Quant®Deoxynivalenol Test kit and Agra Quant® T-2 toxin Test kit. The results indicated a considerable variability of the individual strains in the formation...
Effect of temperature and lactic acid bacteria on the surface growth of Geotrichum candidum
Anna Hudecová, Ľubomír Valík, Denisa Liptáková, Jana Pelikánová, Michal Čižniar
Czech J. Food Sci., 2011, 29(10):S61-S68 | DOI: 10.17221/265/2011-CJFS
The surface growth of Geotrichum candidum isolated from ewes' lump cheese was studied on pure agar medium and that inoculated with Lactobacillus rhamnosus GG and L. paracasei subsp. paracasei CCM 1753. The colony growth rates of fungus calculated from the growth curves were modelled in relation to temperature by the cardinal temperature model with inflection (CTMI). The following cardinal values resulted from the secondary model: Tmin = -3°C, Topt = 27.6°C, and Tmax = 35.4°C and optimal colony growth rate µopt = 5.34 mm/day. A quantitative...
Methods for detection of Bacillus sp., B. cereus, and B. licheniformis in raw milk
Irena NĚMEČKOVÁ, Kateřina SOLICHOVÁ, Petr ROUBAL, Barbora UHROVÁ, Eva ŠVIRÁKOVÁ
Czech J. Food Sci., 2011, 29(10):S55-S60 | DOI: 10.17221/313/2011-CJFS
Totally 75 raw milk samples were analysed with the methods employing the media compared - MYPA, PEMBA, BrillianceTM Bacillus cereus agar, and HiCrome Bacillus agar. The reference method with MYPA seems to be the most suitable for dairy plants laboratories because there is only low risk of mistaken identity. However, the samples containing miscellaneous micro-flora should be heat-inactivated before plating. Both positive and negative strains (totally 132) were isolated. Twelve strains, which could cause problems in the evaluation of the plates, were selected and identified by phenotyping and by PCR methods for Bacillus...
In vitro fermentability of prebiotic oligosaccharides by lactobacilli
Gabriela KUNOVÁ, Vojtěch RADA, Ivana LISOVÁ, Šárka ROČKOVÁ, Eva VLKOVÁ
Czech J. Food Sci., 2011, 29(10):S49-S54 | DOI: 10.17221/306/2011-CJFS
Twelve strains of lactobacilli were tested for their growth and ability to utilise six prebiotics (pure substances and commercially available prebiotics) as a sole carbon source. All strains showed a considerable growth on all prebiotics tested. Inulin was the best carbohydrate source for lactobacilli, followed by lactulose and raffinose. A massive increase of viable cells on commercial prebiotic mixtures (Vivinal, Oligomate 55, and Orafti P95) was also observed. Lysozyme susceptibility was assayed in 13 strains of lactobacilli. Eight out of 13 strains were completely resistant to the lysozyme concentration of 400 µg/ml, in the rest of the strains...
Fermentation of vegetable substrates by lactic acid bacteria as a basis of functional foods
Irena NĚMEČKOVÁ, Hedvika DRAGOUNOVÁ, Marta PECHAČOVÁ, Jana RYSOVÁ, Petr ROUBAL
Czech J. Food Sci., 2011, 29(10):S42-S48 | DOI: 10.17221/282/2011-CJFS
People suffering from lactose intolerance, cow's milk allergy or phenylketonuria or people on low-protein diet are restricted in the consumption of dairy products. Their consumers' basket should be variegated and enriched with probiotics. The main task was to evaluate important growth and metabolic characteristics of lactic acid bacteria in rice, natural rice, corn, chickpea and barley. Suspensions of the respective flours in water (8% w/w) were supplemented with glucose (1% w/w), pasteurised and fermented. Suitable combinations of cultures and substrates enable the growth of microorganisms minimally by t 2 decimal orders. This is connected with a...
Contribution to the immunomodulatory characteristics of probiotic bacteria
Alexandra Šalaková, Jiřina Bártová, Jan Drbohlav, Petr Roubal
Czech J. Food Sci., 2011, 29(10):S36-S41 | DOI: 10.17221/303/2011-CJFS
We monitored the impact of selected probiotic strains on the human immune system. 13 strains of lactic acid bacteria (Lactobacillus acidophilus, Lactobacillus helveticus, Enterococcus faecium, Streptococcus thermophilus, and Propionibacterium freudenreichii subsp. shermanii), used in the production of functional foods, were tested from the point of view of their ability to stimulate a range of cytokines. The selected cytokines have regulatory properties; they affect the progression of inflammation and the inhibition of inflammatory response, and they play a role in humoral immunity, allergies, and cell-mediated...
Stability of selected lactobacilli in the conditions simulating those in the gastrointestinal tract
Šárka HORÁČKOVÁ, Kateřina ŽALUDOVÁ, Milada PLOCKOVÁ
Czech J. Food Sci., 2011, 29(10):S30-S35 | DOI: 10.17221/283/2011-CJFS
The cell survival in the digestive tract is one of the main criteria required for the probiotics. The aim of this study was to evaluate the stability of the selected lactobacilli (Lactobacillus acidophilus CCDM 151; L. casei CCDM 198; L. rhamnosus CCDM 150, and L. fermentum ST 68) in conditions simulating those in the gastrointestinal tract as compared to the commercial probiotic strain Lactobacillus casei LAFTI L-26. The growth of lactobacilli decreased both after 2 h and 4 h incubation in MRS media with increasing concentration of bile salt but all lactobacilli had the...
Application of quantitative approach focused on the competition of lactic acid bacteria culture with coagulase-positive staphylococci under the conditions related to artisanal cheese fermentation
Ľubomír Valík, Alžbeta Medveďová, Denisa Liptáková
Czech J. Food Sci., 2011, 29(10):S23-S29 | DOI: 10.17221/264/2011-CJFS
A quantitative analysis of Staphylococcus aureus growth was carried out in milk fermented with the mesophilic mixed-strain culture of lactic acid bacteria (LAB), in relation to the conditions prevailing during artisanal ewes' lump cheese production. Both the temperature and initial volume of the culture had a dramatic effect on the behaviour of the S. aureus strain under study. Depending on the conditions, the growth, reaching maximal population density (Nmax) and a strong inhibition of S. aureus were observed. Regression analysis of the results enabled us to explain the relationships between...
Differentiation of toxigenic Staphylococcus aureus strains isolated from retail meat products
Zora Šťástková, Renáta Karpíšková, Kateřina Koukalová, Kateřina Bogdanovičová
Czech J. Food Sci., 2011, 29(10):S17-S22 | DOI: 10.17221/270/2011-CJFS
Staphylococcus aureus is a saprophyte and commensal of the skin and mucous membranes in both animals and humans. As a pathogen, it can cause a number of diseases ranging from minor skin infections to fatal sepsis. Toxigenic strains of S. aureus are currently among the leading causes of food-borne intoxication (staphylococcal enterotoxicosis). Food contamination sources can be humans, raw materials, environment, technological equipment, etc. The identification of the origin of S. aureus would be helpful in the detection of the sources and routes of contamination. The aim of our study was to determine the probable origin of...
Occurrence and characteristics of methicillin resistant Staphylococcus aureus and methicillin resistant coagulase-negative staphylococci in raw milk manufacturing
Marcela Vyletělová, Hana Vlková, Ivan Manga
Czech J. Food Sci., 2011, 29(10):S11-S16 | DOI: 10.17221/4443-CJFS
For monitoring the occurrence of MRSA (methicillin resistant Staphylococcus aureus) and MR-CNS (methicillin resistant coagulase-negative staphylococci), cow's, goat's, and sheep's milks (bulk milks and individual samples) were investigated. Human nasal and throat swabs of the farm staff and nasal swabs of animals were also investigated as well. In total 1729 samples were examined and 634 strains were isolated by means of the cultivation method and used in this study. Generic identification of the staphylococci isolates was done performed by biochemical tests and all S. aureus and CNS isolates were checked...
Could the miraculous springs in the Pardubice region be used as drinking water sources?
Marcela Pejchalová, Petra Hanzalová, Radovan Metelka, Jarmila Vytřasová
Czech J. Food Sci., 2011, 29(10):S109-S114 | DOI: 10.17221/304/2011-CJFS
Selected springs in the Pardubice Region were repeatedly examined for analytical and microbiological indicators. Microbiological analyses included the determination of intestinal enterococci, coliform bacteria, E. coli, and the number of colonies cultivated at temperature form 22°C to 36°C. The analyses were carried out according to the relevant CSN ISO norms using the membrane filtration technique and also the alternative cultivation method Colilert®/Quanti-Tray 2000® quantification method using the defined substrate technology. Out of 11 wells and springs examined, only two satisfied the requirements for potable...
Serological and bacteriological evaluation of Salmonella status in swine herds
František Šišák, Hana Havlíčková, Ján Matiašovic, Renata Karpíšková
Czech J. Food Sci., 2011, 29(10):S102-S108 | DOI: 10.17221/311/2011-CJFS
The sera from 690 slaughtered fattening pigs from 15 farrow-to-finish swine herds (12 herds of unknown Salmonella status, 3 herds known as latently infected) in the Czech Republic were examined for Salmonella antibodies in a cross sectional study using an ELISA test. Salmonella seroprevalence ranging from 0% to 20% was found in 14 herds. Seroprevalence of 73.9 was found in 1 herd with previously unknown Salmonella status. A longitudinal study of the three previously identified latently infected herds found seroprevalence ranging from 23.9% to 83.4% in sows after farrowing. Salmonella findings from faeces in...
Utilization of DNA microarrays for detection and identification of selected Fusarium species from the Czech Republic
Lucie Pavlátová, David Novotný, Jan Hodek, Jana Chrpová, Jaroslava Ovesná
Czech J. Food Sci., 2011, 29(10):S93-S101 | DOI: 10.17221/307/2011-CJFS
Fusarium is a serious phytopathogenic fungal genus with producting of many kinds of highly toxic secondary metabolites - mycotoxins. The consumption of Fusarium contaminated food and feed can cause dangerous mycotoxicoses both in humans and animals, therefore the detection of a wider range of Fusarium species in the samples of crops is very important. The aim of our work was to test the reliability of detection and identification of three Fusarium species in infected wheat grains by DNA microarrays versus classical mycological methods and by specific PCR. The in-house DNA microarrays for the detection and...