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Background&Objective: Foodstuffs additives are a general term for materials that are added to the foodstuffs in order to increase durability and to improve the appearance, composition, taste and food nutritional value. Colors are classified in this group and are added to foodstuffs in order to increase their attraction. Colors may cause illness such as allergy, rash and hyper activation in children and also they may debilitate the Immune system, Anaphylaxis reactions may also occur and they may have cancerous effect. The aim of this survey was to analyze status of added colors to the dried sweets which are produced in south of Tehran city. Materials & Methods: 191 samples of dried sweets were randomly collected and analyzed from south of Tehran areas. First, the samples were de-colored by Clorhidric Acid, and then were analyzed after refining by Thin Layer Chromatography (T.L.C) method. Samples were identified by taking Retention Factor (RF values) into consideration. Results: 93.2 percent from the total samples contained colors. Among chromatic samples, 42 samples (22%) out the total samples, contained artificial, non-edible colors and 96 samples (50.3%) from the total samples contained artificial and edible colors (for Industrial Producers) and 40 samples (21%), contained natural colors. Sunset yellow color was detected more than other added colors in sweets. Conclusion: Low costs, stability, PH, purity, and environmental conditions, motivate the producers for high utilization of edible colors without considering their possible hazards and/or their edible quality aspects. It is suggested that, based on the findings of this study and high consumption of colors.

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Background and Objective: Klebsiella species are gram-negative bacteria with positive voges proskauer (VP) reaction. Klebsiella species are found as commensal in human digestive and respiratory system. This group of organisms can create a serious health hazards in hospitalized patients, and their ability to drug resistance is a major health problems. This study was done to evaluate the efficacy of Ciprofloxacin, Ceftizoxims and Carbenicillin on Klebsiella species isolated from hospital specimens. Materials and Methods: In this laboratory study, 1200 clinical samples were isolated from patients in Imam Khomeini hospital, Tehran, Iran. The identification Klebsiella species were carried out according to conventional biochemical tests. The minimum inhibitory concentration (MIC) of carbenicillin, ceftizoxime, and ciprofloxacin antibiotics were determined using Macrodilution broth test. Results: Out of 1200 isolated samples, 25% were identified as Klebsiella species. 73% of identified Klebsiella were obtained from urine samples. Klebsiella.peumoniae with rate of 94% was the most abundant among other species. The results of MIC and minimum bactericidal concentration by using standard microdilution method showed drug resistance range of 16-1024 μg/ml, 4-256 μg/ml and 0.25-16 μg/ml for carbenicillin, ceftizoxime, and ciprofloxacin, respectivley. In general, 94%, 6% and 1% of species were resistance to carbenicillin, ceftizoxime and ciprofloxacin, respectively. Conclusion: Ciprofloxacin and Ceftizoxime are suitable for the treatment of infections due to Klebsiella species.

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Background and Objective: Gastroenteritis due to Salmonella is common in human and considered as a global dilemma of public health. This study was done to determine the Pattern of serotyping and antibiotic resistance of Salmonella in children with diarrhea in Iran. Methods: In this laboratory study, 306 stool samples were collected from children with diarrhea in public health centers in Robat-karim, Tehran province, Iran. The specimens were enriched in Selenite F medium and then cultured on Hekton agar. The identification of Salmonella was carried out by conventional method and antimicrobial susceptibility testing was performed according to CLSI procedures. Results: Out of 306 stool samples, 7.2 % were identified as Salmonella species, as follow: 7 Salmonella typhi, 6 Salmonella paratyphi B, 3 Salmonella paratyphi C, 2 Salmonella paratyphi A and 4 samples were not identifiable. There was a significant relation between presence of WBC in fecal and salmonellosis (P<0.05). In drug sensitivity trends, 92.3% of Salmonella species were sensitive to chloramphenicol, ceftizoxime, Nalidixic acid and Amikacin. Conclusion: This study showed that Salmonella was the cause of children diarrhea in 7.2% in this region.

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Background and Objective: Yersinia enterocolitica is a worldwide pathogen belong to genus Yersinia. The association between acute childhood diarrhea and other diseases caused by Yersinia enterocolitica has been established by several researchers. Due to the lack of sufficient information on other pathogenic Yersinia species, this study was done to determine the prevalence and the pattern of antibiotic susceptibility of atypical Yersinia spp isolated from children, less than 14 years old. Methods: This descriptive cross - sectional study was carried on 384 children with diarrhea whom referred to the Tehran children medical center, Tehran, Iran during August 2011 to August 2012. 384 fecal specimens of children were transferd to the laboratory and cold enrichment in alkaline buffer with pH of 7.2 for 21 days. The samples were cultured in Cefsulodin-Irgasan-Novobiocin Agar (CIN) differential media in 7, 14, and 21 days. The identification of Yersinia species were carried out by conventional procedure. Antibiotic susceptibility test to Ciprofloxacin, Co-trimoxazole, Tetracycline, Chloramphenicol, Erythromycin, Ampicillin, Gentamicin, Penicillin were determined by standard disk diffusion method. Results: Out of 384 fecal samples, 3 (0.7%) were infected with Yersinia. Three species of Yersinia were Y.enterocolitica, Y.Kristensenii and Y.frederiksenii. All three strains were sensitive to Cotrimoxazole, Tetracycline, Chloramphenicol, Ciprofloxacin and Gentamicin. Conclusion: This study showed that atypical Yersinia play important role in diarrhea. Therefore, more attention should be noticed to atypical Yersinia species in addition to Yersinia enterocolitica.

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Background and Objective: Probiotics are beneficial organisms therapeutic within microbial flora. Shigella, Escherichia coli and Salmonella are the most common cause of intestinal infectious diseases that lead to morbidity and mortality in infant and children worldwide. The aim of this study was to evaluate anti-microbial activity of Lactobacillus acidophillus and Lactobacillus ruteri against entero-pathoges by in vitro and in vivo methods. Methods: In this experimental study, the therapeutic effect of the lactobacillus acidophilus ATCC 4356 and ruteri ATCC 23272 against Shigella sonnei ATCC 9290, Escherichia coli ATCC 25922 and Salmonella enterica BAA-708 were evaluated by in vitro (spot agar) and in vivo (BALB/c mice) methods. Weight improvment and survival rate in mice were recorded. Results: Lactobacillus acidophillus and ruteri had protective and therapeutic effect against diarrhea caused by pathogenic bacteria. Probiotics reduced the weight, colonization of pathogens and increased the survival rate of animals (P<0.05). Conclusion: Lactobacillus acidophillus and ruteri has anti-microbial activity and their consumption can be effective in the prevention and also the treatment of intestinal disease.

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Background and Objective: Yersinia is a gram-negative bacillus that cause diarrhea through consumption of contaminated food and water.  This study was performed to identify the atypical Yersinia virulence markers isolated from children with diarrhea.

Methods: This descriptive cross -sectional study was done on 384 fecal samples of 0- 14 years old children admitted at children medical center from August 2011 to August of 2012. Fecal samples, for the enrichment, after 21 days of incubation in alkaline buffer with pH=7.2 at 4degree C, on days 7, 14 and 21 samples were cultured on CIN agar and Mac agar and then confirm the differentiation atypical Yersinia from other typical Yersinia species from fermentation of different sugars. Isolates were tested for marker of virulence including calcium dependence, auto agglutination, Congo red uptake and binding of crystal violet.

Results: Out of 384 stool samples, 4 (1.04%) were infected with Yersinia (Yersinia frederikseni, Yersinia kristensenii and Yersinia enterocolitica). Out of these three, only two samples in association was positive with virulence markers.

Conclusion: Phenotypic markers can be used to study the properties of phenotypic strains of Yersinia.

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Background and Objective: Listeria monocytogenes is an important food-borne intracellular pathogen which can transmit to human through contaminated foods and causing meningitis, meningoencephalitis and abortion. This study was done to determine the frequency, antimicrobial susceptibility and serotyping of Listeria monocytogenes isolated from food samples in Tehran, Iran.
Methods: This descriptive was carried on 150 food samples including vegetables, cheese and meat were collected from supermarkets, open-air markets, and delicatessens in different regions of Tehran, Iran since April to September 2018. The presumptive isolates were characterized biochemically. All L. monocytogenes isolates were further analyzed by serotyping and antimicrobial susceptibility tests.
Results: Out of 150 samples, Listeria spp. was detected in 30 (20%) samples in which 9 (6%) were positive for L. monocytogenes [vegetables (n=4, 44.44%), cheese (n=2, 22.22%) and meat (n=3, 33.33%)]. of the 9 L. monocytogenes isolates, 5 (55.55 %), 3 (33.33 %), and 1 (11.11%) belonged to serotypes 4b, 1/2b, and 1/2a, respectively. The most L. monocytogenes isolates were resistant to Trimetoprime, Sulfamethoxazole, Tetracycline, Streptomycin, Chloramphenicol, and Ciprofloxacin while were sensitive to Penicillin G, Gentamicin, Streptomycin, and Ampicillin, and were intermediately resistant to Ciprofloxacin.
Conclusion: The rate of Contamination of vegetable, cheese and meat samples with L. monocytogenes is important in Tehran, Iran. Due to the potential contamination samples to Listeria, there is necessity need for continuous monitoring and the development of a precise program for identifying this bacterium in Tehran and the whole country.

 

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Background and Objective: Salmonellosis is a gastroentritidis which caused by the different serovars of Salmonella genus, and responsible for morbidity and mortality worldwide. Food born disease is one of the growing problems of human societies especially in developing countries. The aim of this study was to evaluate and serogroup determination of Salmonella isolates from food along with antibiotic resistance pattern.
Methods: This descriptive study was performed on total of 400 in equal of 200 packed and 200 unpacked  samples of (red meat, chicken meat, egg, vegetable) collected in random from distributed in Tehran ,Iran during nine months in 2018. Microbial, biochemical and serological test was performed according to protocol number of 1800 of national standard. Antimicrobial susceptibility test was done by disk diffusion (MAST, Co, UK) method.
Results: Out of 400 samples 8 (2%) was identified as Salmonella. The unpacked foods were more contaminated (75%) compared to packed foods (25%). The most isolated serogrouping were belonging to especially D. Salmonella. The chicken samples were more contaminated (37.5%) than other samples. The isolated Salmonella were mostly resistance to nalidixic acid (75%).
Conclusion: The Salmonella isolated particularly from group 1 showed higher antimicrobial resistance, additional care should be taken in preparation, packaging and supplying the food samples.

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Background and Objective: The emergence of Gram-positive and Gram-negative bacteria resistant to antibiotics is a crisis worldwide. In this study, the antibacterial effect of zinc oxide nanoparticles was evaluated on standard and food isolated strains of Salmonella enteritidis and Bacillus cereus.
Methods: This descriptive laboratory study, zinc oxide nanoparticles were prepared on zeolite materials, and zinc level was determined using XRF. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of ZnO nanoparticles were determined using disc diffusion method.
Results: MIC value for all tested bacteria was 4 mg/ml and MBC values of standard and isolated strains of Salmonella enteritidis were 16 and 8 mg/ml, respectively, and for standard and isolated strains of Bacillus cereus was calculated in the range of 16 mg/ml.
Conclusion: Zinc oxide nanoparticles can inhibit Salmonella enteritidis and Bacillus cereus strains and may have a potential for its replacement with current preservatives to prevent food spoilage in industry.

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Background and Objective: The most common enterohemorrhagic Escherichia coli strain is the O157: H7 serotype, which is one of the most important intestinal pathogens and can cause complications such as hemorrhagic colitis, hemolytic uremic syndrome and acute renal failure. The aim of this study was to evaluate the enterohemorrhagic Escherichia coli causing molecular outbreaks of foodborne illness in Iran.
Methods: In this descriptive cross-sectional study, 189 fecal swab specimens were examined during April to September 2018. All suspected isolates were tested for biochemical tests. The isolates were confirmed by molecular PCR and evaluated by antimicrobial susceptibility tests.
Results: From 189 stool swab samples studied, 98 Escherichia coli isolates were detected based on phenotypic tests. Most of the outbreaks occurred in summer and the prevalence of enterohemorrhagic Escherichia coli was 24.5%, which 4% of them were non-O157H7. Most patients were between 1 and 12 years of age and the highest antibiotic resistance to cotrimoxazole and chloramphenicol was observed at 80% and 79%, respectively.
Conclusion: This study showed an increase in enterohemorrhagic Escherichia coli with 24.5% and an increase in antibiotic resistance to the antibiotics of chloramphenicol, cotrimoxazole and carbapenems. Increased resistance to imipenem and meropenem antibiotics makes it difficult to treat beta-lactamase-resistant strains.

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Background and Objective: Campylobacter is one of the most important pathogens causing bacterial gastroenteritis, which is usually transmitted through the food of animal origin. This study was done to evaluate the status of Campylobacter in diarrheal food outbreaks compared to other microbial agents.
Methods: This descriptive study was performed on 305 diarrheal swab samples from 102 food outbreaks during six months from spring to the end of summer 2018. Presence of Campylobacter species were assessed according to the protocol of the General Directorate of Laboratory Affairs.
Results: Out of 305 samples, 8 (2.6%) were identified as Campylobacter species, 3 (37.5%) Campylobacter and 5 (62.5%) Campylobacter coli. The epidemiology of the outbreaks showed that female (54.5%), average age of 16-30 years (28.2%), consumption of salads and vegetables (16.1%) and living in the cities (59.7%) were the most cases.
Conclusion: This study showed that in addition to classic pathogens such as Salmonella, Shigella, Escherichia coli, attention also should be paid to Campylobacter bacteria. In addition, recognizing epidemiological factors can play an important role in preventing and controlling food outbreaks.

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Background and Objective: Yersinia is water and foodborne organism that cause human gastroenteritis. This study was done to evaluate the frequency of Yersinia species isolated from children diarrheal samples and chicken meat in Tehran, Iran.
Methods: In this descriptive study 250 sample of diarrhea of children referred to the Children's Medical Center, Tehran, Iran and 250 samples of chicken were collected and examined for Yersinia infection during July 2016 to March 2017. Isolation method was performed based on initial enrichment in phosphate buffer for 3 weeks in refrigerator (cooling in c4 +) and then using KOH as secondary enrichment and culture on CIN agar medium. Biotyping method was used to determine pathogenic strains.
Results: In this study, 5(2%) isolates from pediatric diarrhea samples and 20 isolates (8%) from chicken meat samples were obtained from Yersiniaenterocolitica. Biotyping of human Yersiniaenterocolitica isolates identified 3 cases of biotype 1A, one case of biotype 1B, one case of biotype 2 and from chicken meat isolates, 16 isolates belonged to biotype 1A and 4 isolates belonged to biotype 1B.
Conclusion: Presence of common pathogenic 1B and non-pathogenic 1A biotypes in pediatric diarrhea samples and chicken meat can indicate the cause of diarrhea in children.