نشریه بهداشت مواد غذایی
سال دوم شماره 2 (پیاپی 6، تابستان 1391)

In this study contamination of milk and dairy products with pathogenic bacteria in Iran has been reviewed. There are many surveys in some cases، while there is no information about some pathogenic bacteria in milk or very few data is available. It should be point out that the results come from the cross sectional surveys are needed for further epidemiological and experimental studies. In general the contamination of milk and dairy products has decreased in the course of time as the production methods and producer’s knowledge increased. On the other hand application of new and precise methods of detection and investigation of bacteria lead to excess detection of pathogenic microorganisms in milk. Therefore regular continuation of cross sectional studies along with using precise and sensitive methods of sampling and analysis of bacteria are necessitated. Besides making available of needed data about the contamination of milk and milk products with pathogenic bacteria، this information make enable to adopt the effective preventive precautions for elimination or reduction of contamination.

Escherichia coli is among the most important intestinal foodborne bacterial pathogens. The objective of this study was to estimate the prevalence of E. coli in traditionally-made ice creams at retails of Khoy city. Moreover، the antibiotic profile of the isolates was investigated. For this، during April to September 2012، 150 ice cream samples collected from markets and confectionery shops. The samples were analyzed for the presence of E. coli. Afterwards، the antibiotic susceptibility and resistance of the isolates was evaluated on 10 different antibiotic using Kirby-Bauer test. According to the results، 31. 33% (47. 150) of the samples were found positive for E. coli. The results of antibiogram test indicated that the highest level of sensitivity was determined for ceftizoxim (80. 85%)، ciprofloxacin (78. 73%)، and ceftriaxone (74. 47%)، respectively. In contrast، the most resistance antibiotics were amoxicillin (95. 74%)، oxacilin (82. 98%)، kanamycin (61. 7%)، respectively. The results revealed that the prevalence of E. coli، as the indication of fecal contamination، in traditionally made ice cream in Khoy retails and the antibiotic profile of the isolates were noticeable.

Chicken sausage is among popular meat products which in turn، has a share in daily diets. Accordingly، study on meat products and the variation of their characteristics during processing and storage conditions are of the uppermost importance. In this study، chicken sausages containing 90% chicken meat were manufactured under similar conditions except for the added oil type. That is to say، the two batches of chicken sausages were manufactured by the addition of canola and soybean oils in their formula. The samples were stored at 4 to 5 °C for 45 days. With 15-day interval، the samples were analyzed for the fatty acid profile (palmitic، stearic، oleic، linoleic and linolenic acids)، microbial (total psychrotrophic bacteria and lactobacillus) and chemical [moisture content، pH، peroxide and thiobarbituric acid (TBA) values as well as free fatty acid (FFA)] properties. Except for the peroxide value، all parameters showed statistically significant (p<0. 05) variations throughout the storage period. Moreover، the PUFA/SFA was in the recommended range in all samples excluding the sample containing soybean oil on day 15. The results concluded that the samples formulated with canola oil undergo less variation during storage period.

Nitrite and nitrate are the key ingredients and play a multifunctional role in meat curing technology. Despite all of their desirable effects، the addition of nitrite to meat is the major cause of carcinogenic N-nitrosamines formation. In this study، the amount of residual nitrite and nitrate in meat products containing 61% to 80% meat were assessed. The samples were obtained at the fourth day of their production from Shiraz retails and analyzed using high performance liquid chromatography (HPLC). According to the results، the mean concentrations of residual nitrite and nitrate were estimated at 36. 96 ± 7. 38 and 85. 81 ± 5. 5 mg/kg in small-diameter (1. 5-2 cm) sausages. Meanwhile، in largediameter (5. 5-8 cm) sausages the residues were estimated at 20. 97 ± 3. 28 and 124. 85±5. 3 mg/kg، respectively. In all analyzed samples، the residual nitrite level was found below the permitted level of 120 mg/kg which indicated the application of allowed concentrations of nitrite in such products. The mean values of residual nitrite and nitrate concentrations were statistically different (p<0. 05) between small and large-diameter sausages. Although nitrate was not used in these products، detection of relatively high levels of nitrate could be originated from the ingredients of sausages such as meat، water، spices as well as vegetable or might be entered via the conversion of nitrite to nitrate during the primary stages of processing. Finally، it was concluded that HPLC is a rapid، sensitive and selective method and provides accurate results.

Isolation، identification and grouping of staphylococcal enterotoxins in milk is of great importance،since these toxins are considered as a major potential source of humans illness. In this study، 75staphylococcus aureus strains isolated from buffalo milk were assessed. For this، extracted DNA wasanalysed by multiplex-PCR for the presence and diversity of genes encoding the common classicalstaphylococcal enterotoxins. Results revealed that one of the isolates haboured both sec and sebgenes; meanwhile، three other isolates contained merely sec gene. Moreover، the gene encoding theproduction of enterotoxin-A was not detected in any of the isolates. It was concluded that the diversityof genes encoding the classical enterotoxins of S. aureus isolated from Tabriz area was low.

Pickle fermentation is a natural process in which microorganisms could affect the quality of the product. Amongst، Lactobacillus plantarum strains that improve the quality of fermented pickle. In this study، in order to produce safe and desirable fermented pickle، local cucumbers were immersed in 5% and 7% (w/v) brine solutions. The samples were inoculated with 0، 4 ×106، 4 ×107 and 6 ×108 cfu/ml of L. plantarum. The samples were kept at ambient temperature for 15 days followed by 30 days storage at 4 °C and 25 °C. The bacterial populations were analyzed during the aforementioned stages of fermentation and storage. According to the results، the maximum quantity (8. 57 log10 cfu/ml) of L. plantarum was observed in the 9 day of fermentation and in the samples inoculated with 6 ×108 cfu/ml and kept in 5% brine solution. Moreover، compared to the other samples، the population of yeasts and aerobic mesophilic count were the least in the samples inoculated with 6 ×108 cfu/ml of L. plantarum and stored in 7% brine solution. During the storage period، the population of L. plantarum، yeasts and aerobic mesophilic in the samples stored at 25 °C were higher than the samples stored at 4 °C. Results revealed that in the 30 day of storage، the highest load (5. 47 log10 cfu/ml) of L. plantarum was observed in the samples kept in 7% brine solution at 4 °C. It was concluded that providing the condition that favors the appropriate growth of L. plantarum could help to hinder the growth of undesirable organisms in fermented pickle.

Iodine is an essential element in human diet and is found in many types of animal-origin foods. Nevertheless، iodine defect is a serious problem in many countries throughout the world. This study was aimed to determine the iodine contents of beef، lamb as well as eggs at ShahreKord retails. Forty beef، 40 lamb and 60 egg samples were obtained from ShahreKord markets during spring and winter of 2011. Iodine content of the samples was determined by acid digestion and Sandell-Kolthoff-base method. According to the results، the iodine content (mean ± SD) of lamb in winter and spring was 11. 32 ± 3. 79 and 105. 65 ± 52. 635 μg/kg، respectively. Meanwhile، the iodine content for beef samples was estimated at 16. 17 ± 5. 69 and 115. 25 ± 41. 18 μg/kg in winter and spring، respectively. Moreover، it was found that iodine content of egg yolk in winter was 340. 40 ± 122. 60 μg/kg and in spring was 462. 63± 62. 71 μg/kg. However، iodine content of egg albumin in winter and spring was 33. 01 ± 14. 56 and 47. 87 ± 14. 40 μg/kg، respectively. In this study، a significant (p>?) relationship was not observed between the iodine content of albumen and egg yolk. It was concluded that beef، lamb and egg could be considered as a significant source of iodine for human.

Food safety knowledge is considered as an important precautionary principle for foodborne illnesses as well as protecting environment from contamination. The purpose of this study was to investigate the knowledge and attitudes of soldiers of food safety and sanitation. A cross-sectional-analytical study was performed on 191 of Arak Malek-Ashtar garrison soldiers and the survey questionnaire contained personal information about food safety knowledge and attitude. According to the results، 57% of the soldiers had a good knowledge، 18% an average and 25% had a low degree of knowledge about food safety and sanitation. Although all soldiers had good attitude towards food safety، a statistically significant correlation (p< 0. 01) was observed between the knowledge of soldiers with medical education and the other soldiers. Results did not reveal significant difference between various age categories in terms of knowledge. Since، some of the soldiers had low degree of knowledge، it is essential to include food safety courses during military training.