JOURNAL OF FOOD HYGIENE
Year:2018 | Volume:8 | Issue:1 (29) |Papers Count:8

The presence of histamine in foods is an important indicator of food spoilage and can also cause food poisoning in consumers. Therefore, monitoring of histamine level in food is important. This paper has focused on the comparing of capillary zone electrophoresis (CZE) with HPLC for the determination of histamine in tryptic soy broth. For this reason, the culture media was inoculated with a standard strain of histamine-producing Staphylococcus epidermidis TYH1, as well as S. capitis and S. carnosus strains harboring histidine decarboxylase-hdc. The migration time of histamine in CZE assay and retention time of HPLC were found 5. 4 and 12 min, respectively. The calibration graph was linear ranged 6. 25 to 200 μ g/ml which was estimated using the regression equation of y=0. 000004x (r2=0. 999) for both methods. Determination of histamine produced by these three strains indicated no significant differences using CZE with HPLC methods. The results show that the CZE is suitable for the determination of histamine in bacterial culture, since, there is no need for initial preparation, simplicity, sensitivity and low cost.

Nowadays, many studies have been conducted to substitute the chemical preservatives with naturally occurring compounds, including plant essential oils. In this research, Golpar essential oil was added to Dough samples at concentrations of 0 (control), 100, 250, 500 and 1000  l/l and after packaging, were stored at refrigerator for 40 days. The samples were subjected to microbial (enumeration of yeasts and molds, yoghurt starter bacteria and coliforms), chemical (acidity, pH, fat and solids-non-fat) as well as sensory characteristics (taste and odor) assays. Results showed that with the increasing of the essence concentration, the populations of yeast and mold were reduced (P<0. 05), however, the effect of Golpar essential oil on starter bacteria was insignificant. The number of starter bacteria increased towards day 10, followed by a decrease until the end of storage time. Although during the storage period, acidity and pH were increased and decreased, respectively, the effect of essential oil on fat content and solids-non-fat was not significant. Sensory evaluations in terms of taste and odor revealed that the treated samples had significant (p< 0. 05) difference in comparison with control groups. Besides, the samples containing 250 μ l/l gained the highest score. It was concluded that Golpar essential oil can be efficiently used in Dough formula as a good natural preservative and flavoring agent.

Identification of bacteriocin-producing lactic acid bacteria (LAB) has been noticeable by most researchers. Surveys showed that LAB bacteriocins have remarkable antagonistic effects against foodborne pathogens. Consequently, these bacteriocins could be used as natural preserving for foods. In this research, the antimicrobial effect of supernatants derived from 10 standard and native strain of LAB (previously isolated from raw milk and traditional yogurt) were evaluated against Listeria innocua, Bacillus cereus, Shigella flexneri, Escherichia coli, Staphylococcus aureus, Yersinia enterocolitica, and Klebsiella pneumonia. All treatments were conducted in three replicates and the mean values of the inhibition zone diameters were compared. Moreover, protein nature of the antibacterial agents was identified by trypsin treatment. According to the results, LAB showed a satisfactory antagonistic effect against indicator organisms. Among the LAB, 15E strain demonstrated the highest (6. 03 mm) and lowest (0. 167 mm) inhibitory impact on S. flexneri and Y. enterocolitica, respectively. It was revealed that E. coli and S. flexneri were identified as the most sensitive and B. cereus as the most resistant strain against native LAB bacteriocins. Trypsin treatment confirmed the protein nature of the antagonistic agents produced by the LAB. It was concluded that T2 native strain could be considered as the most effective strain versus gram-negative bacteria such as S. flexneri, E. coli, Y. enterocolitica, and K. pneumonia.

Butter is a dairy product made by churning fresh or fermented cream and is one of the most highly concentrated forms of fluid milk. The aim of this survey was to assess loads of microbial contamination in traditional and pasteurized butter samples marketed in Birjand city, Iran. For this propose, totally 100 samples, including 60 samples of traditional butter and 40 samples of pasteurized butter, were collected randomly under sterile conditions and were analyzed according to the protocol of Iranian National Standards Organization. Data were analyzed with SPSS-19 software. The statistical analysis of data showed that the rate of contamination with coliforms, Escherichia coli, Staphylococcus aureus and mold and yeast in the traditional butter samples were higher than Iranian Standard limits in 8. 3%, 3. 3%, 1. 7% and 61. 7%, respectively; meanwhile 7. 5%, 7. 5% and 27. 5% of the pasteurized samples were contaminated with coliforms, E. coli, and mold and yeast, respectively. Contamination with S. aureus was not found in any of the pasteurized samples. There was no significant difference between contamination with coliforms, E. coli and S. aureus in traditional and pasteurized samples, however, this difference between mold and yeast was significant (P< 0. 05). The results indicated that the microbial contamination in traditional and pasteurized butter samples was higher than standard limits in 65% and 27. 5% of the samples, respectively which needs strict preventive measures.

PTDI and PTWI value. At the same time, a significant negative correlation between Pb and Cd and a significant positive correlation between length and condition factor with 99% probability level was found. Risk assessment on non-carcinogenicity showed the highest and lowest THQ in Zn and Cd respectively, the same was the case for TTHQ formation and for none of the metals was not >1. Also, the allowable level for in heavy metals Cd, Pb, and Zn. Mean's Non Carcinogenicity risk.

Enterotoxin-producing strains of Staphylococcus aureus can cause food poisoning through the consumption of contaminated dairy products. Essential oil (EO) of Zataria multiflora Bioss. contains components with antibacterial and antifungal properties. The present study was conducted to determine the minimum inhibitory concentration (MIC) of Z. multiflora Boiss. EO on S. aureus isolated from raw milk. Extraction and gas isolation of the EO was provided and analyzed by Chromatography/mass spectrometry. A total of 84 samples of raw milk from a dairy farm in Semnan were analyzed for the presence of S. aureus. Fourteen S. aureus strains were isolated from raw milk. The chemical composition of hydrodistilled EO of Z. multiflora Boiss was analyzed by Chromatography/mass spectrometry. A total of 25 compounds representing 98. 59% of the oil were identified: carvacrol (50. 53%), thymol (14. 7%), p-cymene (7. 9%), Carvacryl acetate (3. 85%) and Trans-caryophyllene (3. 4%). The MIC of Z. multiflora Boiss. Using broth microdilution method, MIC of EO on all of the S. aureus isolates was estimated at 0. 0001-0. 004. Based on results, the EO of Z. multiflora Boiss possesses antibacterial activity on S. aureus isolated from raw milk.

Food hygiene measures and its proper maintenance during distribution, purchase, and consumption are important principles to prevent food-borne infections in consumers. The aim of this study was to evaluate knowledge and attitude of students of medical sciences of Kashan University about food hygiene and storage. This cross-sectional study was conducted on 286 male and female students. Data obtained through questionnaires containing questions on demographic data as well as knowledge and attitudes to food hygiene and storage. The results showed that mean knowledge and attitude scores of the students about food hygiene and maintenance were 62. 23± 13. 53% and 2. 37± 0. 41%, respectively. The knowledge score between male students was significantly more than females (P<0. 01). The students’ attitude score was increased significantly (P<0. 01) with the increasing of their age. Moreover, the knowledge score of the students with a previous history of food intoxication was significantly (P<0. 01) more than those who had no food intoxication experience. The outcomes of this study showed that the students had an acceptable knowledge level of food hygiene and storage.

Antibiotics are commonly prescribed for humans and animals for the prevention and treatment of various microbial diseases. This study was carried out for the evaluation of enrofloxacin residue in quail meat in Yazd city by HPLC. For this, 50 meat samples were collected from quail meats that supplied in Yazd from winter to spring in 2014-2015. Results showed that 11 samples (22%) were positive for enrofloxacin residue. The minimum and maximum concentrations of enrofloxacin in the samples were 3. 08 and 117. 09 μ g/Kg, respectively. The mean value of enrofloxacin concentration in the positive samples was 8. 6 ± 21. 28 μ g/Kg. The concentration of enrofloxacin in 14% of the samples was higher than European Maximum Residual Level (30 μ g/Kg). In conclusion, for improvement of hygienic quality of quail meat, it is necessary to apply suitable strategy for legality of withdrawal time for antibiotic consumption.