Assessment of the antifungal activity of Lactobacillus and Pediococcus spp. for use as bioprotective cultures in dairy products.

Fungi are commonly involved in dairy product spoilage and the use of bioprotective cultures can be a complementary approach to reduce food waste and economic losses. In this study, the antifungal activity of 89 Lactobacillus and 23 Pediococcus spp. isolates against three spoilage species, e.g., Yarrowia lipolytica, Rhodotorula mucilaginosa and Penicillium brevicompactum, was first evaluated in milk agar. None of the tested pediococci showed antifungal activity while 3, 23 and 43 lactobacilli isolates showed strong antifungal activity or total inhibition against Y. lipolytica, R. mucilaginosa and P. brevicompactum, respectively. Then, the three most promising strains, Lactobacillus paracasei SYR90, Lactobacillus plantarum OVI9 and Lactobacillus rhamnosus BIOIII28 at initial concentrations of 105 and 107 CFU/ml were tested as bioprotective cultures against the same fungal targets in a yogurt model during a 5-week storage period at 10 °C. While limited effects were observed at 105 CFU/ml inoculum level, L. paracasei SYR90 and L. rhamnosus BIOIII28 at 107 CFU/ml respectively retarded the growth of R. mucilaginosa and P. brevicompactum as compared to a control without selected cultures. In contrast, growth of Y. lipolytica was only slightly affected. In conclusion, these selected strains may be good candidates for bioprotection of fermented dairy products.

[Dogs as a possible source of human Campylobacter infecfions]. / Psi jako mozný zdroj jampylobakterových infekcí cloveka.

OBJECTIVES: The aims of this study were to obtain current information on the prevalence and species representation of bacteria of the genus Campylobacter in dogs in Moravia and to evaluate the risk factors affecting their occurrence with respect to possible transmission to the human population. MATERIAL AND METHODS: Rectal swabs of dogs obtained in the routine practice of veterinarians in the South Moravian and Olomouc -regions were examined from May 2013 to December 2014. The basic tests were performed in laboratories of the State Veterinary Institute in Olomouc and the University of Veterinary and Pharmaceutical Sciences Brno. To detect Campylobacter spp., the samples were cultured on mCCDA (modified charcoal-cefoperazone-deoxycholate agar). Suspected colonies were confirmed by MALDI-TOF MS (Biotyper Microflex, Bruker) or using specific PCR which allows to distinguish between the species C. jejuni, C. coli, C. lari and C. upsaliensis. A detailed history was obtained from questionnaires completed by the dog owners. RESULTS: From a total of 258 rectal swabs examined, 41 samples were positive (16 %). The most frequently detected species was C. jejuni, followed by C. upsaliensis a C. coli. There was only one sample of C. lari. The evaluation of the questionnaire data showed that the frequency of Campylobacter spp. and their species representation depended on the age of the animals, the composition of feed and the clinical signs of the disease. CONCLUSION: Young dogs on a homemade diet and with diarrhea may be considered a risk group in terms of possible transmission of Campylobacter infections from pets to humans. Households with young children are the most affected group in the Czech Republic and EU countries. As such, they should be given a high priority with respect to the basic hygiene rules if they breed dogs, especially puppies.

The Effect of High-Pressure Processing on the Survival of Non-O157 Shiga Toxin-Producing Escherichia coli in Steak Tartare: The Good- or Best-Case Scenario?

Samples of steak tartare were artificially contaminated with a cocktail of Shiga toxin-producing Escherichia coli (STEC) O91, O146, O153, and O156 to the level of 3 log and 6 log CFU/g. Immediately after vacuum packing, high-pressure processing (HPP) was performed at 400 or 600 MPa/5 min. Some of the samples not treated with HPP were cooked under conditions of 55 °C for 1, 3, or 6 h. HPP of 400 MPa/5 min resulted in a 1-2 log reduction in the STEC count. In contrast, HPP of 600 MPa/5 min led to the elimination of STEC even when inoculated to 6 log CFU/g. Nevertheless, sub-lethally damaged cells were resuscitated after enrichment, and STEC was observed in all samples regardless of the pressure used. STEC was not detected in the samples cooked in a 55 °C water bath for 6 h, even after enrichment. Unfortunately, the temperature of 55 °C negatively affected the texture of the steak tartare. Further experiments are necessary to find an optimal treatment for steak tartare to assure its food safety while preserving the character and quality of this attractive product.

The Pork Meat or the Environment of the Production Facility? The Effect of Individual Technological Steps on the Bacterial Contamination in Cooked Hams.

The aim of this study was to analyse the influence of the contamination level of fresh meat on the bacterial population in raw material before cooking and on the microbiota of cooked hams following heat treatment. The effect of incubation temperatures of 6.5 and 15 °C on the results obtained was also evaluated during the bacteriological investigation. The total viable count (TVC), the number of Enterobacteriaceae and lactic acid bacteria (LAB) were determined in the samples. LAB were isolated from 13 samples out of the 50 fresh meat samples. The species most frequently detected included Latilactobacillus sakei, Leuconostoc carnosum, Enterococcus gilvus, Latilactobacillus curvatus, and Leuconostoc gelidum. The meat sampled after the brine injection and tumbler massaging showed higher bacterial counts compared to fresh meat samples (p < 0.001). The heat treatment destroyed the majority of the bacteria, as the bacterial counts were beneath the limit of detection with a few exceptions. Although the primary cultivation of samples of cooked hams did not reveal the presence of LAB, their presence was confirmed in 11 out of 12 samples by a stability test. Bacteria of the genus Leuconostoc were the most numerous.

Journal article publishing in the social sciences and humanities: A comparison of Web of Science coverage for five European countries.

This study compares publication pattern dynamics in the social sciences and humanities in five European countries. Three are Central and Eastern European countries that share a similar cultural and political heritage (the Czech Republic, Slovakia, and Poland). The other two are Flanders (Belgium) and Norway, representing Western Europe and the Nordics, respectively. We analysed 449,409 publications from 2013-2016 and found that, despite persisting differences between the two groups of countries across all disciplines, publication patterns in the Central and Eastern European countries are becoming more similar to those in their Western and Nordic counterparts. Articles from the Central and Eastern European countries are increasingly published in journals indexed in Web of Science and also in journals with the highest citation impacts. There are, however, clear differences between social science and humanities disciplines, which need to be considered in research evaluation and science policy.

Occurrence of Foodborne Agents at Food Service Facilities in the Czech Republic.

HIGHLIGHTS: Contamination of food service facilities in the Czech Republic by foodborne agents was determined. Bacillus cereus, Staphylococcus aureus, and Escherichia coli were detected in almost 50% of samples. The occurrence of B. cereus, S. aureus, and E. coli depended on the season of the year. Regular monitoring of food service facilities for agents of foodborne disease is necessary.

Identification of lactobacilli isolated from food by genotypic methods and MALDI-TOF MS.

Lactobacilli are bacteria with important implications in food and feed fermentation. Detailed knowledge of the lactobacilli composition is of high relevance to food and health control, various industrial or biotechnological applications, etc., but accurate identification of the Lactobacillus species is not an easy task. In this study, three methods, i.e. polymerase chain reaction (PCR), amplified 16S rDNA restriction analysis with restrictase MseI (16S-ARDRA), and the matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) were evaluated for their capabilities to identify Lactobacillus species. After comparison of the three methods on a set of 19 type/reference Lactobacillus strains, 148 strains isolated from dairy and meat products were characterized by PCR and MALDI-TOF MS. The strains were differentiated into nine and ten lactobacilli species by PCR and MALDI-TOF MS, respectively, with nine of these species being congruent. The success rates of species level assignment were 77% for PCR and 93% for MALDI-TOF MS that proved superior in the species identification. However, to differentiate between closely related Lactobacillus species, MALDI-TOF MS needs to be used in combination with genotypic techniques to achieve a more reliable identification.