Research Publications (Food Safety)

Spores of Bacillus megaterium were immobilized on a sensor disk by entrapment method followed by addition of pretreated milk and fluorogenic substrate, i.e., diacetate fluorescein with a response time of about 20 ± 5 min with ≥0.25 μg/L detection limit. Fluorescence was measured semiquantitatively using microbiological plate reader at specific excitation and emission spectra, i.e., 485 and 535 nm, respectively.

A novel target-enriched multiplex polymerase chain reaction (Tem-PCR) assay for the simultaneous detection of Salmonella spp., Listeria monocytogenes and Escherichia coli O157:H7 was developed in the present study. The invA, hly and rfbE genes were selected as target genes for identifying Salmonella spp., L. monocytogenes and E. coli O157:H7, respectively.

This study aimed to evaluate the effects of temperature, pH, sugar content and antimicrobial components on the growth of 11 yeast isolates in apple juice (12 °Brix, pH 4.0). The results showed that reduction of the storage temperature to 4C could achieve a complete inhibition of test strains, and the temperature required to kill all the initial yeast inoculum (103 cfu/mL) within 20 min ranged from 46 to 55C, depending on the isolate.

The objectives of this study were to detect bacteria on restaurant menus, to determine the bacterial transfer from menus to consumers' hands and to determine the survival of bacteria on menu surfaces. Local restaurant menus were sampled at different periods of operation. The average total plate count (TPC) was 28 (0–210) cfu/15 cm2 menu sampling area during “busy” periods and 15 (0–85) cfu/15 cm2 menu sampling area during “less busy” periods.

This study elucidated the effect of NaCl on the thermal resistance and cell morphology of Escherichia coli strains. E. coli O157:H7 NCCP11142, E. coli O111 ATCC12795 and E. coli O26 ATCC43887 were incubated in tryptic soy broth formulated with 0% NaCl (nonhabituated) as well as broth formulated with 2% and 4% NaCl (NaCl-habituated) at 35C. Nonhabituated, 2% NaCl-habituated and 4% NaCl-habituated E. coli O157:H7, E. coli O111 and E. coli O26 were heat-challenged at 50C.

In the present study, microbiological, chemical and sensory changes of sausage samples produced from fillets of Chondrostoma regium, Luciobarbus mystaceus and Capoeta trutta implemented with traditional and liquid smoke were investigated during a storage period of 70 days at 4 ± 1C. The results of microbiological, physicochemical, chemical and sensory analyses showed that there were no differences between sausages smoked with either liquid smoke or traditional smoke (P > 0.05).

The objectives of study were to assess presence of Listeria monocytogenes, perform serotyping and investigate antibiotic resistance in raw milk and dairy products. A total of 210 milk and dairy products including white (n = 20) and kashar cheese (n = 20), ice cream (n = 20), butter (n = 20), cokelek (n = 10), kuymak (n = 10) and farm cheese (n = 10) were obtained from Samsun, Turkey.

The effects of the addition of oregano (0.25% v/v) and thyme (0.25% v/v) essential oils (EOs) on the microbiological, biochemical and sensory characteristics of a Tunisian dry fermented poultry meat sausage were investigated. The antimicrobial activity of oregano and thyme EOs improved the hygienic quality of dry fermented sausages by reducing the Enterobacteriaceae counts, total coliform counts and Staphylococcus aureus counts.

Fresh vegetables are a frequent cause of foodborne disease outbreaks because they often do not undergo heat treatment prior to consumption. Pathogenic Escherichia coli strains are the major causative agents of produce-related outbreaks.

The aim of our study was to assess the antibiotic resistance among commercially available probiotic Lactobacilli. A total of 30 isolates were characterized after isolation from 19 commercial products, including Lactobacillus rhamnosus, Lactobacillus acidophilus, Lactobacillus casei, Lactobacillus reuteri, Lactobacillus plantarum and Lactobacillus fermentum. All the isolates were further subjected to antibiotic susceptibility test using disc diffusion method against a total of 45 antibiotics.

The combined effects of ultraviolet (UV) light C (0.34 to 20.13 kJ/l2) and superatmospheric O2 (>85%) packaging on the respiration rate, atmospheric composition, microbiological growth and nutritional quality of fresh-cut arugula stored for 10 days at 5C were studied. All treatments performed under increased O2 levels exhibited a reduction in the respiration rate throughout the cold storage. High microbial load of the raw material were found.

Rifampicin-resistant (RifR) strains have often been used in studies of Escherichia coli O157:H7 to assure more specific recovery. The present study compared the heat inactivation kinetics of rifampicin-resistant variants of pathogenic and nonpathogenic E. coli O157 strains with those of the wild-type parental strains. Spontaneous RifR derivatives of 11 pathogenic and six nonpathogenic E. coli O157 strains were selected.

This study evaluated the biological properties of milk fermented with Lactobacillus acidophilus with and without several amounts of royal jelly including: total viable count, pH, titratable acidity, antioxidant activity and inhibitory activities of angiotensin 1-converting enzyme (ACE), α-amylase, and growth of colorectal (SW480) and skin (MV3) cancer cell lines. The bound phenolic extract after acid hydrolysis had better biological properties.

Five yeast strains were tested for their ability to remove T-2 toxin from yeast extract peptone dextrose medium. The ability of Saccharomyces cerevisiae 1221 (SC1221) was the strongest among five strains, and 36.50 ± 1.40% of T-2 toxin was removed after incubation at 30C for 96 h. The mode of removal was physical binding rather than biotransformation.

The growth behavior of Listeria monocytogenes in the presence of typical spoilage microorganisms on poultry breast fillets (Pseudomonas spp., Brochothrix thermosphacta, Enterobacteriaceae, Lactobacillus spp., total viable count) was investigated.

Rapid and accurate identification of Pseudomonas species, especially in drinking water, is of great importance for human health. In the present study, we aim to develop a fast and reliable verification method, which does not require intensive microbiological procedures.

Motile Aeromonas spp. were isolated from 49 (44.1%) of 111 meat samples (74 fish and 37 ground beef). In this study, 31 (27.9%) isolates were identified as Aeromonas caviae, nine (8.1%) as A. hydrophila and nine (8.1%) as A. veronii biovar sobria. We detected the phenotypic and genotypic virulence factors.

In this work, the combined effect of bioactive compounds (tea tree essential oil, propolis extract and gallic acid) and storage temperature (15 and 5C) on microbiological and sensory quality of fresh-cut celery, leek and butternut squash was studied. It was confirmed that a good control of refrigeration temperature limits the growth of spoilage and pathogenic microorganisms.

The antimicrobial activity of essential oils on Clostridium perfringens type A and the influence of such oils on mortadella quality were assessed. The anticlostridial effects of several essential oils and their combinations were identified and some essential oils and their combinations were selected for further study in mortadellas supplemented with 75 ppm sodium nitrite and inoculated with C. perfringens.

From clinical and microbiological perspectives, it is important to know which serogroups, virulence, and antibiotic resistance genes and antibiotic resistance patterns are present in Shiga toxin-producing Escherichia coli strains in poultry meats from turkey, quail and ostrich that have recently been added to the cart households. These were investigated in the present study. Five-hundred poultry meat samples were collected from the supermarkets of Isfahan province, Iran.

This study aimed to evaluate the effect of gelatin–alginate film containing 1.5% oregano essential oil (OEO) on the shelf life of rainbow trout (Oncorhynchus mykiss) slices during refrigerated storage over a period of 15 days. The blend film was prepared at 75% fish gelatin to 25% sodium alginate ratio and OEO was added to the film formulation.

This study aimed to evaluate the effect of a natural antimicrobial agent (Pronat) on selected quality indicators during the shelf life of vacuum-packed frankfurters made from jumbo squid (Dosidicus gigas) muscle. Frankfurters with and without Pronat (0.1%) were vacuum-packed and stored at 2–4C for up to 28 days.

The occurrence of outbreaks of Cronobacter sakazakii causing necrotizing meningitis in China highlights the need for strain characterization of this pathogenic species. In this study, SMM system was utilized to mine for new molecular markers of C. sakazakii. One C. sakazakii-specific CDS (>ref|NC_009778.1|:c1077329-1076055) with a length of 1,275 bp was used to design a primer set. A PCR assay was developed and optimized to detect C. sakazakii.

The study investigated fresh tomato fruits (Roma VF variety) prepared into paste, proportioned into different samples with each receiving different concentrations of ginger, ginger and garlic powder (2 and 4% w/w) and stored over a period of 8 weeks. The total viable (TVC), lactic acid bacteria (LAB) and yeast counts of the samples were enumerated on a weekly basis while the pure microbial isolates were identified.

Cronobacter species are foodborne pathogens associated with neonatal meningitis, sepsis and necrotizing enterocolitis through consumption of contaminated powdered milk. However, there are no specific targets used for differentiating Cronobacter species. The DNA-based assay and polyphasic analysis have facilitated the detection and typing of Cronobacter species in foodborne outbreaks. In this study, polymerase chain reaction (PCR) and dot hybridization for detecting Cronobacter spp.