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Hanna Różańska, Mirosław Michalski and Jacek Osek

Abstract

One hundred and ninety seven samples of molluscs representing different species were tested for the presence of antibacterial substances using a microbiological diffusion test - “4-plate” method. It was found that 58 samples (29.4%) were positive. The percentage of positive samples depended on species and varied from 0 (Ostrea edulis, Perna canaliculis, Cardium edule, Myretrix lyrata, Mercenaria mercenaria) to 41.2 (Mytilus edulis) and 50.0 (Tapes semidecussatus and Ruditapes phillipinarium). The randomly performed confirmatory analyses using HPLC -MS/MS method did not show the presence of any known antibiotics.

Open access

Monika Kurpas, Kinga Wieczorek and Jacek Osek

Abstract

In 2015 in the European Union member states listeriosis caused 270 deaths. Food is the route of transmission in 99% of all human infection cases. Several studies from different countries have shown that the presence of Listeria monocytogenes in food can be as high as 58.3%. One of the most important ways to protect food from these microorganisms is to prevent the spread of the bacteria at processing plants at different stages of food production chain. The ability of L. monocytogenes to survive in extreme conditions and to form biofilms on various surfaces is a significant challenge for food safety. Removal of these bacteria from niches in processing plants is difficult and requires the use of sanitisers and precise equipment cleaning. The presence of L. monocytogenes in processing environment at slaughterhouses, deli meat factories or in retail may be a reason of cross-contamination. Proper hygienic systems applied by workers in food preparing places and knowledge about different routes of spreading of these bacteria may effectively decrease the risk of food contamination. Standardised legal regulations and control of meat product manufacture should be a fundamental way to protect food from L. monocytogenes contamination.

Open access

Hanna Różańska and Jacek Osek

Abstract

One hundred and nine samples of honey representing different botanical types were microbiologically retested for the total number of aerobic bacteria per 1 g, the presence of anaerobic bacteria in 0.1 g, and number of yeasts and moulds per 1 g after one year of storage. The samples displayed different levels of microbiological contamination. The mean of total number of aerobic bacteria varied from 1.9 x 101 CFU/g to 4.6 x 103 CFU/g depending on the type of honey. This value, in comparison with year 2010 was lower in the case of 75 samples (68.8%), higher in 14 samples (12.8%), and stable in the remaining 20 samples (18.4%). The mean number of moulds and yeasts was 9.8 x 101 CFU/g and it was lower in 46 samples (42.2%). In 46 samples no changes were noted. The presence of anaerobic spore forming bacteria was noted in 18 samples. The presence of these microorganisms in 73 honey samples (67.0%) did not change since 2010.

Open access

Kinga Wieczorek and Jacek Osek

Abstract

A total of 1229 samples, including 406 bovine hides and 406 corresponding carcasses at the slaughter level, as well as 417 beef meat from local supermarkets, were tested for the presence of Salmonella sp. Eighteen (1.5%) samples were positive for the target microorganism, and the highest prevalence (2.2%) was found in meat, followed by carcasses (1.2%) and hides (1.0%). Among the isolated strains, Salmonella enterica serotypes Enteritidis (six isolates) and Schleissheim (six strains), followed by Dublin (four contaminated samples) were the most predominant. The antimicrobial resistance analysis against nine antimicrobials with the MIC technique revealed that most isolates were sensitive to all antibacterial agents. However, one S. Typhimurium of carcass origin was multidrug resistant, and displayed the resistance to four antimicrobials, i.e. ampicillin, streptomycin, tetracycline, and sulphametoxazole. Furthermore, one S. Enteritidis (from carcasses), two S. Dublin (of beef origin), and one S. London (from meat) strains were resistant to sulphametoxazole. The restriction enzyme analysis with XbaI resulted in eight different PFGE types. The obtained results suggest that cattle may be an underestimated source of pathogenic Salmonella for consumers.

Open access

Hanna Różańska and Jacek Osek

Abstract

Raw, inhibitors free milk was spiked with penicillin G, ampicillin, cloxacillin, and ceftiofur at the levels 1 × MRL, 1.5 × MRL, and 2 × MRL, and oxytetracycline at the levels 100 ppb (MRL), 500 ppb and 700 ppb. The samples were stored at 4 ± 2 C and -18 ± 2 C and were tested every day and week, respectively. The analyses were performed using microbiological diffusion test Delvotest SP-NT and receptor assay CHARM ROSA MRL BL/TET for the detection of β-lactams and tetracyclines. In cooled samples antibiotics were detected up to 72 h. After this time, the samples were acidulated and not suitable for investigations. In frozen samples, depending on type and concentration of antibiotics, these substances were detected from one week (penicillin G - 4 ppb) to 35 weeks (ampicillin and ceftiofur).

Open access

Kinga Wieczorek and Jacek Osek

Abstract

A total of 2668 swabs from poultry (n = 2166), pig (n = 311), and cattle (n = 191) carcasses were collected in slaughterhouses all over Poland and tested for the presence of Campylobacter. It was found that 1319 (49.4%) of them were contaminated with these bacteria. The percentages of the positive samples were different in each year of the study and the highest proportion of Campylobacter contaminated samples occurred in 2009, when 64.1% of investigated carcasses were positive. On the other hand, the lowest prevalence of Campylobacter was observed in 2013, in the last year of the survey. In all kind of carcass samples both C. jejuni and C. coli were identified, although the pork meat was more contaminated with C. coli (75.3% of positive samples) than with C. jejuni (24.7%), whereas poultry was nearly equally positive for C. jejuni and C. coli (50.6% and 49.4% respectively). The analysis of seasonal contamination of the carcasses revealed that more positive results were found during the second half of year than between January and June. The prevalence of Campylobacter showed that in all provinces, except one (Pomorskie), the mean percentage of the positive samples was above 40%. The most contaminated samples were identified in Lubelskie (69.3%) and Zachodniopomorskie (66.3%) regions. The obtained results showed that slaughtered animals in Poland, especially broilers, were often contaminated with Campylobacter, either C. jejuni or C. coli.

Open access

Bernard Wasiński, Hanna Różańska and Jacek Osek

Abstract

The aim of the study was a preliminary determination of occurrence of extended spectrum β-lactamases (ESBL)- and AmpC-producing Escherichia coli (E.coli) in raw meat samples collected from slaughter-houses located in different regions of Poland. A total of 141 samples were tested, comprising 78 pork samples, 44 beef samples, and 19 chicken meat samples. Isolated and identified E. coli strains were examined for the ESBL and/or AmpC β-lactamases production by the use of four disc diffusion and minimum inhibitory concentration tests. All strains positive in one or both tests were examined by PCR for the presence of the blaCTX, blaTEM, blaSHV, and blaCMY-2 group genes. During the study, 154 E. coli strains were isolated from 95 samples. Among these, 18 (11.7%) strains were identified in phenotypic tests as ESBL-producing and seven (4.5%) strains as AmpC-positive. The presence of the genes encoding selected ESBL-s (TEM, CTX, SHV) was identified in 14 of the strains recognised as ESBLpositive in phenotypic tests. All AmpC-positive isolates showed the presence of the CMY-2 group encoding genes. One of these strains had also the CTX-M and TEM genes, and four of them expressed the TEM marker.

Open access

Bernard Wasiński, Hanna Różańska and Jacek Osek

Abstract

In the present study, 25 Escherichia coli strains isolated from beef, pork, and poultry meat, and producing extendedspectrum β-lactamases (ESBL) (18 strains) or AmpC- cephalosporinases (7 strains) were tested for antimicrobial resistance using the minimum inhibitory concentration method with 16 antimicrobial agents. All examined strains were resistant to ampicillin and the first-generation cephalosporins. Variable resistance to the third-generation cephalosporins (40%-100% among ESBLproducing strains and 0-72% among AmpC-producing strains) was noted. Less than 30% of examined strains were resistant to ciprofloxacin. All isolates were susceptible to the fourth-generation cephalosporins, cephalosporins connected with inhibitors of β-lactamases, carbapenems, and gentamycin

Open access

Mirosław Michalski and Jacek Osek

Abstract

Introduction: Growing consumption of shellfish is associated with an increased risk of food poisoning. The study was carried out on live bivalve molluscs available on the Polish market between 2009 and 2013. Material and Methods: ELISA was used for the determination of the following marine biotoxins: paralytic shellfish poison (PSP), amnaesic shellfish poison (ASP), and diarrhoeic shellfish poison (DSP). The molluscs, of which seven species were examined, were obtained from wholesale companies and markets. Results: Marine biotoxins were detected below the permitted levels in 67.6% of the samples. The maximum amounts of PSP and ASP biotoxins were found in great scallops (532.6 μg/kg and 1.0 mg/kg respectively) and the peak for DSP was in blue mussels (107 μg/kg). Conclusion: The analysis of toxicological status of raw bivalve molluscs available on the market in Poland indicates that they are safe for consumers.

Open access

Weronika Korpysa-Dzirba and Jacek Osek

Abstract

The aim of the study was to investigate if the enterotoxigenic strains of S. aureus isolated from raw milk are able to produce staphylococcal enterotoxins (SEs) A - E. A total of 168 of S. aureus isolates from raw milk collected in the south - east region of Poland (Lubelskie Province) were tested for SE production by the ELFA, while multiplex PCR was applied for detection of enterotoxin genes (sea, seb, sec, sed, see). It was found that 20 (11.9%) out of 168 strains were positive for one or more classical SE markers and 19 of them produced a detectable level of enterotoxins. The results obtained by mPCR and ELFA were in agreement, when the presence of A, B, and D toxin types was tested; whereas SEC was not found by the ELFA although the S. aureus was positive for the respective gene. The results of the two methods showed that mPCR identified one more strain potentially producing enterotoxin than the ELFA, which may suggest that the enterotoxigenic S. aureus are not always able to express the toxin protein.