نشریه بهداشت مواد غذایی
سال دوم شماره 3 (پیاپی 7، پاییز 1391)

The present study was aimed to review the contamination of meat and meat products with pathogenic bacteria in Iran. Little information is available about the contamination of meat and meat products with Bacillus cereus, because of the low contamination rate with the microorganism. The situation is about the same with Brucella, as the microorganism can hardly be seen in the muscles. However, not too many information is available on the contamination with Campylobacter jejuni, even though, the contamination of chicken meat with the campylobacter was addressed. Clostridium butolinum was the main discriminated bacterium to contaminate fish and its products and canned meats. Studies revealed that the big portions of meat were less likely contaminated with E. coli compared to the minced meat. Our study showed that the cross contamination of sausage is often occurred after the production chain. The situation was possibly attributed to the improvement of hygienic conditions of slaughter-houses and meat industries. Limited information was found on the contamination with Listeria monocytogenes and available data indicate that the microorganism can be present in meat and meat products. The most important factor for prevention of contamination is restricted inspection of slaughtered animals before slaughter and omission of diseased animals. Much information was accessible on the cross contamination with Salmonella in Iran and elsewhere. Salmonellosis is not common in the slaughtered animals despite its epidemiological and public health issues. The problem was also associated with the restricted inspection. Study about the staphylococcal contamination of meat was proportionately numerous. The contamination was mostly occurred in the minced Kebab in the warm seasons of the year. Generally, a low percentage of such contaminations were found in the meat products and sausage, in the surveys.

The main objective of this study was to determine the effect of attenuated adjunct culture of lactobacillus plantarum on the lipolysis of UF-white cheese as measured by acid degree value, the fatty acids profile, physicochemical, microbial and sensory characteristics during ripening. The results showed that, treated UF cheeses exhibited no significant (p>0.05) differences in chemical composition (dry matter, fat, salt and pH) in comparison with the control UF cheeses throughout 60 days of ripening. Total bacterial count and mesophilic lactobacillus count in the UF cheeses using attenuated adjunct starter were significantly (p<0.01) higher than the control cheeses after 45 days of ripening. The results of fatty acid profiles revealed that due to increasing of the lipolysis in the first 30 days of ripening, the samples containing attenuated adjunct lactobacillus plantarum had significantly (p< 0.01) lower percentages of fatty acids with medium and short chains (C4:0 -C14:0) in comparison with the control cheeses while the percentage of fatty acids with long chains (C16:0 -C18:3) increased. Acid degree value, as indicated by total free fatty acids was significantly (p<0.01) higher in cheeses using attenuated adjunct lactobacillus plantarum. In organoleptic evaluation, UF cheeses received significantly (p<0.01) higher total scores than the control samples on day 45. Finally, it could be concluded that cheeses produced by attenuated adjunct lactobacillus plantarum have more nutritional quality than the control UF cheeses.

Importance of heavy metals in food safety and detrimental effects of their high concentrations in food stuff is well documented. In this study, concentrations of Fe, Zn, Cu, Cd and Pb in kidney, liver and muscle tissues of cow and sheep at Hamedan retails were evaluated. A total number of 180 samples was assessed for the amount of heavy metals as ppb in wet weight. For this, wet-digestion method was used to determine the concentration of given elements by ICP (Varian ES-710). Results showed that the highest concentration of heavy metals was determined in the liver and kidney samples, while the lowest concentration was found in muscle tissue. Among the heavy metals, Fe in cow’s liver had the highest concentration (25507±879 ppb) and Cd in muscle tissue of sheep has the lowest concentration (192±54 ppb). In overall, accumulation of heavy metals in tissues of cows was higher than sheep. Statistical comparison of accumulated metals concentration in various tissues of these two animal groups showed significant difference (P<0.001). Regarding the maximum acceptable concentration approved by EU, the concentration of heavy metals was lower than the allowed level, except for Cd and Pb. Due to the toxicity of Cd, the concentration of Cd was compared with the maximum acceptable limit of WHO. Results revealed that the concentration of Cd was higher than acceptable level in all tissues except for muscle tissues (P<0.001). Mean concentration of most metals in this study was found higher in cow tissues than sheep. It seems that cows are more tolerant against the accumulation of toxic metals. Moreover, mean concentration of Fe and Cu was higher in liver which is justifiable by the fact that liver is a storage organ. Since kidneys are responsible for the removal of wastes, mean concentration of Cd and Pb was determined highest in kidney.

Salmonella infection is among the main food-borne gastrointestinal disease. Meat has been recognized as a major source of human illness caused by Salmonella serovars. The presence of Salmonella was detected in 60 samples of fresh beef from retailsof Sanandaj. The presence of Salmonella was assessed by conventional culture method and confirmed by PCR assay. To confirm the identification of isolated colonies as Salmonella spp. and determining serovars as typhimuriumand enteritidisserovars, a multiplex PCR assay, using three pairs of primers were employed. S141 and S139 for InvAgene, specific for the genus of Salmonella, Fli15 and Tym for FliCgene, specific for typhimurium serovar and Prot6e-5 and Prot6e-6 for Prot6E gene, specific for Enteritidisserovar.12 samples 20% were determined as contaminated with Salmonella sppwith microbial culture method but with PCR method only seven samples 11.66% were confirmed. 4 samples (6.6%) of isolated colonies were confirmed as SalmonellaTyphimuriumand any number of isolated colonies were confirmed as Salmonella Enteritidis, the other isolated colonis were belong to other salmonella serovars. This study showed a relatively highprevalence of salmonella in fresh beef from Sanandaj.

A comparative study was conducted to investigate a relationship between concentration of arsenic with protein, lipid, ash and moisture content in Cyprinus carpio, Oncorhynchus mykiss, Aristichthys nobilis, Hypophthalmichthys molitrix, Ctenopharyngodon idella, Scomberomorus commerson, Scomberomorus guttatus and Otolithes ruber. A total of 72 sample of common carp, Bighead carp, silver carp and grass carp fishing from Azadegan fish farming center, Ahvaz; Rainbow trout from Cheshme Dimeh and Scomberomorus commerson, Scomberomorus guttatus and Otolithes ruber caught with gill net from Hendijan. Wet-digestion method was performed prior to arsenic determination in the samples. The level of arsenic was measured by atomic absorption spectrophotometer. The results showed that concentration of arsenic in the muscle of fishes was 269.87 ± 20.96 μg/Kg. Moreover, levels of protein, lipid, ash and moisture in the samples were estimated at 19.67±0.78 g/100, 2.45±0.45 g/100, 1.49±0.23 g/100, 78±1.89 g/100, respectively. Results also showed a positive correlation between the accumulation of arsenic in muscle of fishes with levels of protein, lipid, ash and moisture (p<0.05).

This is a study aimed to investigate the effect of lactic acid bacteria including Lactobacillus acidophilus and Sterptococcus thermophilus (as thermophilic culture), Lactococcus lactis subsp. lactis, cremoris and diacetylactis, Leuconostoc citrovorum (as mesophilic culture), Lactobacillus acidophilus, Lactobacillus casei, Bifidobacterium lactis and a mixed culture of L.acidophilus, L. casei and B. lactis on fatty acid profile, conjugated linoleic acid (CLA) and atherogenic index (AI) of butter. Fatty acid analysis with gas chromatography indicated that application of thermophilic and mixed culture decreased the ratio of saturated to unsaturated fatty acid; whereas, the butters made with L. acidophilus had the highest content of CLA. Moreover, AI in the samples prepared with thermophilic cultures was the least. Sensory evaluation of the treatments revealed no significant differences (p> 0/05) in appearance and color. However, the butters prepared with thermophilic and mesophilic cultures had more desirable taste in comparison with the samples made with L. acidophilus, L. casei and B. lactis. From the nutritional point of view, the adverse effect of butter could be diminished via the application of selected lactic acid bacteria.

Contaminants are damaging factors of the ecosystems. Amongst, heavy metals are due to their toxicity, persistence and bio-accumulation are of great concern even in low concentrations. Kurdistan province with an annual production of 30,000 tons of strawberry produces 88 percent of the strawberry in Iran. In this study, 25 samples were obtained randomly from soil (depth of 0-30 cm), leaf and strawberry crop of all five existing farms located on the road of Sanandaj to Kamyaran. The samples were transported to laboratory and acid digestion was performed on the samples. Afterwards, the quantity of cadmium, arsenic, lead, zinc and copper were measured using atomic emission device. The results revealed that metal concentrations of cadmium, zinc and copper (0.01, 6.03, 13.67 mg/kg, respectively) were lower than the standards of FAO/WHO. Meanwhile the concentrations of heavy metals of arsenic and lead (36.88, 3.57 mg/kg, respectively) were higher than the defined standards (with 95% confidence level). It seems that the overuse of chemical fertilizers and pesticides is the main cause of heavy metal contaminations in the strawberry farms.

Raw milk is among the highly perishable foods which are subjected to various environmental contaminations following milking. In this study, the factors influencing bacterial load of bulk-milk were investigated. For this purpose, 100 samples were obtained from dairy farms around Esferayen during spring, summer and autumn of 2009. The samples were taken in three stages: after milking, before transportation from dairy farm, and before delivering to milk-collection-center. The samples were analyzed for total bacteria count (TBC). To determine the factors which could influence the TBC of raw milk, a questionnaire sheet where designed. Statistical analysis were performed by means of logistic regression (genmod procedure), using SAS software (version 8.2). According to the results of this study, maintaining cold chain throughout the transportation and storage of raw milk, prevention of mastitis, cleaning and sanitizing of containers and equipments, age and breed of dairy cattle as well as indirect factors such as education level of dairy farmers, distance to milk-collection-center had significant effects (P<0.05) on microbial count of bulk-tank-milk. It was concluded that to reduce bacterial in raw milk, it is crucial to maintain cold-chain throughout milking process, wash teats with sanitizers, improve the hygienic condition of the milking utensils as well as to improve the overall quality of personnel education.