This study aims at evaluating the effects of Zataria multiflora (Z. multiflora) essential oil (EO) on growth, aflatoxin production and transcription of aflatoxin biosynthesis pathway genes. Total RNAs of Aspergillus parasiticus (A.parasiticus) ATCC56775 grown in yeast extract sucrose (YES) broth medium treated with Z. multiflora EO were subjected to reverse transcription- polymerase chain reaction (RT-PCR). Specific primers of nor-1, ver-1, omt-A and aflR genes were used. In parallel mycelial dry weight of samples were measured and all the media were assayed by high-pressure liquid chromatography (HPLC) for aflatoxinB1 (AFB1), aflatoxinB2 (AFB2), aflatoxinG1 (AFG1), aflatoxinG2 (AFG2) and aflatoxin total (AFTotal) production. The results showed that mycelial dry weight and aflatoxin production reduce in the presence of Z. multiflora EO (100 ppm) on day 5 of growth. It was found that the expression of nor-1, ver-1, omt-A and aflR genes was correlated with the ability of fungus to produce aflatoxins on day 5 in YES medium. RT-PCR showed that in the presence of Z.multiflora EO (100 ppm) nor-1, ver-1 and omtA genes expression was reduced. It seems that toxin production inhibitory effects of Z. multiflora EO on day 5 may be at the transcription level and this herb may cause reduction in aflatoxin biosynthesis pathway genes activity.

Salmonella is widely distributed throughout the world and can be found in poultry industry, animal breeding centers, food and feedstuffs of all geographical regions. This study was conducted to determine and identify Salmonella serovars isolated from poultry, calves and foodstuffs (poultry and animals products such as egg and meat). A total of one hundred isolates of Salmonella serovars including Salmonella Typhimurium, Salmonella Enteritidis, Salmonella Infantis, Salmonella Gallinarum and Salmonella Pullorum consecutively were subjected to the conventional culture, biochemical and serological assays. The utility of molecular multiplex PCR was investigated to identify and differentiate among five Salmonella serovars which were identified according to the presence of rfbJ, fljB, invA, and fliC genes in S. Typhimurium, sefA, invA and spv genes in Salmonella Enteritidis, fljB, fliC and invA genes in Salmonella Infantis, hut and slgC genes in both Salmonella Gallinarum and Salmonella Pullorum and speC gene specifically in Salmonella Gallinarum. Biochemical assays and serotyping are complicated to directly differentiate between Salmonella Gallinarum and Salmonella Pullorum because of their antigenic similarity. According to the results, Multiplex PCR can be considered as simple, rapid, accurate and useful test to identify and differentiate among Salmonella serovars.

Disseminated candidiasis is a serious problem in public health that results from the invasion of Candida species, in particular Candida albicans. The aim of this study was to compare the efficacies of Zataria multiflora essential oil and itraconazole in clearing C. albicans from the visceral organs of BALB/c mice suffered from disseminated candidiasis. Zataria multiflora essential oil was extracted using Clevenger-type apparatus and analyzed by gas chromatography mass spectrometry (GC-MS). For clearance experiment, mice (20-25 g, N=8 per group) received essential oil at doses of 30, 48 and 64 mg/kg and itraconazole at dose of 200 mg/kg intraperitoneally (IP) 2 days before and after intravenous inoculation of 0.5 × 106 C. albicans blastospores. The treated animals were sacrificed on day 20, and 0.1 g of the tissue homogenates was plated onto specific media. In GC-Mass, the main components of the essential oil were carvacrol (61.29%) and thymol (25.18%). The results demonstrated that IP administration of 64 mg/kg of the essential oil had the highest efficacy in reducing C. albicans and produced 39.5, 21.8, 141.5, 174 and 501-fold reductions in mean CFUs per 0.1 gram in Candida infections of the liver, spleen, lungs, brain and kidneys, respectively, compared to positive control. Itraconazole showed significantly more responsiveness than the essential oil at dose of 30 mg/kg in clearing C. albicans from the kidneys (P<0.02), brain (P<0.02) and spleen (P<0.04), and less responsiveness than that of 64 mg/kg in clearing the organism from the brain (P<0.01), lungs (P<0.0005) and kidneys (P<0.0005), whereas no significant difference was observed between this drug and Z. multiflora at dose of 48 mg/kg. These data explain the increased rate of yeast clearance and reduced dissemination to the viscera of Z. multiflora treated mice.

In the present work, the effects of Zataria multiflora Boiss. essential oil (EO) against growth and citrinin production by Penicillium citrinum ATCC 1156 were evaluated in culture media and mozzarella cheese. The growth was completely inhibited at 200 ppm on potato dextrose agar, and minimum fungicidal concentration of the EO was estimated at 400 ppm. EO strongly suppressed the growth and citrinin formation in media with a dose‐dependent manner. At 200 ppm in yeast extract sucrose (broth) flasks, mycelial dry weight and citrinin production significantly reduced by 87.5 and 92.4%, respectively (P < 0.05). The EO at all concentrations had an inhibitory effect against fungal growth and citrinin production by P. citrinum in mozzarella cheese but no concentration of EO tested was able to absolutely prevent the fungal growth and citrinin production in mozzarella cheese. It is concluded that this EO could be safely used as a preservative material on some kinds of food such as cheese to protect them from fungal contaminations. Practical Applications The significant (P < 0.05) inhibitory effect of the essential oil (EO) on growth and citrinin production by Penicillium citrinum presented in this study can propose the use of the EO as an antifungal compound in the food industry.

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