ABSTRACT
Although Helicobacter pylori has a significant impact on the occurrence of severe clinical syndromes, its exact ways of transmission and origin have not been identified. According to the results of some previously published articles, foods with animal origins play a substantial role in the transmission of H. pylori to humans. The present investigation was carried out to study the vacuolating cytotoxin A [vacA] and cytotoxin associated gene A [cagA] genotypes status and antibiotic resistance properties of H. pylori strains recovered from minced-meat and hamburger samples. A total of 150 meat product samples were collected from supermarkets. All samples were cultured and the susceptive colonies were then subjected to nested-PCR, PCR-based genotyping and disk diffusion methods. 11 out of 150 samples [7.33%] were positive for H. pylori. All the isolates were further identified using the nested-PCR assay. Prevalence of H. pylori in hamburger and minced-meat samples was 1.42% and 12.5%, respectively. S1a, m1a and cagA were the most commonly detected genotypes. The most commonly detected combined genotypes in the H. pylori strains of minced-meat were s1am1a [10%], s1am1b [10%] and s2m1a [10%]. Helicobacter pylori strains of meat products harbored the highest levels of resistance against ampicillin [90.90%], erythromycin [72.72%], amoxicillin [72.72%], trimethoprim [63.63%], tetracycline [63.63%], and clarithromycin [63.63%]. Hamburger and minced-meat samples may be the sources of virulent and resistant strains of H. pylori. Meat products are possible sources of resistant and virulent strains of H. pylori similar to those vacA and cagA genotypes. Using healthy raw materials and observation of personal hygiene can reduce the risk of H. pylori in meat products
ABSTRACT
Considering the ever increasing population and industrialization of the developmental trend of human life, we are no longer able to detect the toxins produced in food products using the traditional techniques. This is due to the fact that the isolation time for food products is not cost-effective, and even in most of the cases, the precision of practical techniques like bacterial cultivation and other techniques suffers from operator errors, or the errors of the mixtures used. Hence, with the advent of nanotechnology, the design of selective and smart sensors has turned into one of the greatest industrial revelations of the quality control of food products that, in few minutes time and with a very high precision, can identify the volume and toxicity of the bacteria. In this research, based on the bacterial antibody's connection to nanoparticles, a sensor was used. In this part of the research, as the basis for absorption for the recognition of bacterial toxin, medium sized silica nanoparticles of 10 nm in the form of solid powder were utilized with Notrino brand. Then the suspension produced from the agent-linked nanosilica, which was connected to the bacterial antibody, was positioned near the samples of distilled water, which were contaminated withStaphylococcus aureus bacterial toxin with the density of 10[-3] molar, so that in case any toxin exists in the sample, a connection between the toxin antigen and the antibody would be formed. Finally, the light absorption related to the connection of antigen to the particle-attached antibody was measured using spectrophotometry. The 23S rRNA gene that is conserved in allStaphylococcus spp. was used as the control. The accuracy of the test was monitored by using the serial dilution [l0[-6]] of overnight cell culture of Staphylococcus spp. bacteria [OD[600]: 0.02 = 107 cell]. It showed that the sensitivity of PCR is 10 bacteria per ml of cells within few hours. The results indicated that the sensor detects up to 10-[4] molar density. Additionally, the sensitivity of the sensor was examined after 60 days; by the 56 day, it had confirmatory results, which started to decrease after this time. Comparison of practical nanobiosensory method with the conventional methods including culture and bio-technology methods [such as polymerase chain reaction] confirmed its accuracy, sensitiveness and uniqueness. It also reduces the time from hours to 30 minutes
Subject(s)
Exotoxins , Silicon Dioxide , Nanoparticles , Genotyping Techniques , Multiplex Polymerase Chain ReactionABSTRACT
We are no longer able to detect the toxins produced in food products using the traditional techniques. This is due to the fact that the isolation time for food products is not cost-effective and even in most of the cases. Hence with the advent of nanotechnology, the design of selective and smart sensors is one of the greatest industrial revelations of the quality control of food products. This was an laboratory experimental study. In this technique, based on the bacterial antibody connection to nanoparticle, a sensor was used. In this part of the research, as the basis for absorption for the recognition of bacterial toxin, medium sized silica nanoparticles of 10 nano meter in form of solid powder were utilized with Notrino brand. Then the suspension produced from agent-linked nanosilica which was connected to bacterial antibody was positioned near the samples of distrilled water, that were contaminated with Staphylococcus aureus bacterial toxin with the density of 10-3, so that in case any toxin exists in the sample, a connection between toxin antigen and antibody would be formed. Finally, the light absorption related to the connection of antigen to the particle attached antoibody was measured using spectrophotometry. The results indicate that the sensor, up to 10-4 of density is detectable. Additionally, the sensitivity of the sensors were examined after 60 days, the sensor by the 56 day had confirmatory results and started to decrease after those time periods. Nano-particles have unique property in bioanalysis. They have high speed and high sensitivity along with cost effectiveness
Subject(s)
Exotoxins , Biosensing Techniques , Nanotechnology , Silicon DioxideABSTRACT
The behaviour of Escherichia coli O157:H7 was studied during the manufacture and storage of Iranian white cheese in brine. Cheese was manufactured using pasteurized cow milk and inoculated with E. coli O157:H7 with inoculum level of 10[3] cfu/ml. Four treatments were designed. Cheeses were made with or without starter culture and kept immersed in 6 or 8% salt brine during ripening and storage. Cheese samples were analysed for E. coli O157:H7 during manufacture and storage period. During cheese manufacture the number of E. coli O157:H7 increased by 10[6] cfu/g, but during ripening and cheese storage the number of organism decreased significantly in the cheese samples made with starter culture [P<0.05]. The results showed an inhibitory effect of starter culture on E. coli O157:H7, but the organism can survive in this kind of cheese for up to 60 days of storage, respecting using starter culture, salt brine concentration and cheese storage time
ABSTRACT
Broiler carcasses are considered to be the major source of salmonella detection and enumeration of salmonella in this product are two criteria for evaluation of hygienic quality of the slaughterhouses and the product itself. In this study, contamination of broiler carcasses produced in poultry Industrial slaughterhouses in Tehran province was assessed using three tube MPN methods. According to our results 69 percent of the samples were salmonella positive while not detected the salmonella in the rest of samples. Enumeration of salmonella per carcass indicated that the average number of salmonella in 62/72 of salmonella positive carcasses was 49/5 and in 7/6 percent 2605 and in 16/48 percent 279/5 and in 2/3 percent upper 3300. Our results also showed that number of salmonella per per gram and 2 cm2 of positive carcasses in 93/42 percent were 0/054 MPN /gr and 0/047 MPN/cm and in 4/38 2 2 percent 1/695 MPN/gr and 1/4 MPN/cm and in 1/5 percent upper 1/7 MPN/gr and 1/5 MPN /cm. The statistical analysis in this study results and calculates the ratio and average indicates that the mean contamination of carcasses exanimate was low although frequency contamination was high
Subject(s)
Animals , Salmonella , Abattoirs , Chickens , Food ContaminationABSTRACT
To study the effect of zataria multi flora Boiss essential oil, acetic acid, temperature and storage time on probable growth of salmonella typhimurium in brain heart infusion broth. Multiple factorial analysis of bacterial growth. Salmonella typhimurium. Log probability percentage [Log P%] for growth of salmonella typhimurium was investigated in Brain Heart Infusion [BHI] broth in response to different concentration of Zataria multiflora Boiss. essential oil [0.0. 0.03 and 0.06%] and acetic acid [pH, 7.4 and 6] during 43 days storage at three temperature [35,25 and 15 [degree sign] C]. The log P% of S. typhimurium was affected significantly [P<0.05] by different concentrations of essential oil, pH levels, storage temperature and their interaction. The Log P% of S. typhimurium in BHI broth [pH, 7.4] with 0% essential oil at 35, 25 and 15 [degree sign] C were 1.07, 1.07 and 0.41, respectively. This log P% in response to 0.03 and 0.06% essential oils were -2.93, -3.24 and -4.23, and -4.23, -4.23 and -4.23, respectively. The Log P% of S. typhimurium in BHI broth [pH, 6] with 0% essential oil at 35, 25 and 15 [degree sign] C were 2, 0.76 and 1.41, respectively. This Logp% in response to 0.03 and 0.06% essential oils were -1.93, -2.59 and -4.23, and -4.93, -4.93 and -4.93, respectively. At recent conditions, growth has been completely suppressed. Based on the results of this study, Zataria multiflora Boiss. essential oil can be used as a growth inhibitor for salmonella in food products
ABSTRACT
The growing interest in the substitution of chemical food preservatives, both antimicrobials and antioxidants, by natural ones has fostered research on the vegetable source and screening of plant extracts and essential oils in order to identify acceptable natural alternatives. In this study, log probability percentage [Log P%] of growth of Salmonella typhimurium in Brain Heart Infusion [BHI] broth as affected by different concentrations of Zataria multiflora Boiss essential oil [0.0, 0.03 and 0.06%] during 21 days storage at three temperatures [35, 25 and 15[degree]C] was investigated. The Log P% of S. typhimurium was affected significantly [P < 0.05] by different concentrations of the essential oil. The Log P% of S. typhimurium in BHI broth with 0% essential oil at 35, 25 and 15[degree]C were 1.07, 1.07 and 0.41 respectively. While in BHI broth with 0.03 and 0.06% essential oils were -2.93, -3.24 and -4.23 and -4.23, -4.23 and -4.23 respectively. According to the results, the Log P% of growth of S.typhimurium was decreased by increasing of the concentration of essential oil
ABSTRACT
The growing interest in the substitution of chemical food preservatives, both antimicrobials and antioxidants, by natural ones has fostered research on the vegetable source and screening of plant extracts and essential oils in order to identify acceptable natural alternatives. In this study, log probability percentage [Log P%] of growth of Staphylococcus aureus in Brain Heart Infusion [BHI] broth as affected by different concentrations of Zataria multiflora Boiss essential oil [0.0, 0.03 and 0.06%] during 22 days storage at three temperatures [35, 25 and 15[degree]C] was investigated. The Log P% of S. aureus was affected significantly [p < 0.05] by different concentrations of the essential oil. The Log P% of S. aureus in BHI broth with 0% essential oil at 35, 25 and 15[degree]C were -0.89, 1.24 and 1.55 respectively. While in BHI broth with 0.03 and 0.06% essential oils were -0.45, 0.24 and -4.21 and -0.45, -0.45 and -4.45 respectively [strong inhibitory action]
ABSTRACT
During the years 1982-1987 a study was carried out about the rate of the incidence of foodborn infections and intoxications in Tehran which in many cases the consumption of traditional ice cream was the responsible foodstuff. The high incidence of foodborn infections and intoxication in this study was the motivation for a survey on the contamination of traditional Iranian ice cream with important bacteria associated with foodborn infections and intoxications. During the years of 1992-1994, within present study, a total of 390 samples of ice cream were obtained from five different areas in the city of Tehran and analyzed for the detection and enumeration of common and important pathogenic foodborn bacteria. From 150 samples, 122 [81.30%] showed Enterobacteriacae count more than 10[2] per gram of ice cream. In 106 [70.6%] and 2 [1.3%] of samples atypical E.coli and typical E.coli observed respectively. Fifty six samples out of 280 [20%] samples contained more than 10/ g of staphylococcus aureus. From 260 samples, 28 [10.75%] showed Bacillus cereus count more than 10/g and one sample out of 141 samples was shigella positive. No salmonella, Listeria monocytogenes and campylobacter jejuni was isolated from the samples. The survey on the incidence of food infections and intoxications during the study [1992-1994] showed a close correlation between the prevalence of etiological agents and the cases of foodborn infections and intoxications reported from public health agency of the country