JOURNAL OF FOOD MICROBIOLOGY
Year:2018 | Volume:4 | Issue:4 |Papers Count:8

Arcobacters are gram-negative, lack-of-spore and curved-shaped bacteria which are differentiated fromcampylobacter genus by growing up in presence of oxygen and low temperatures. Arcobacter butzleri isthe most prevalent species of this genus known as zoonotic and new pathogen. With the aim of isolationand identification of the Arcobacter butzleri from poultry meat supplied in the slaughterhouses and retailstores, this study was conducted in the Tonekabon city. 140 samples of the poultry meat, including hen(97 samples), duck (25 samples), Turkey (18 samples) were collected, studied and tested in two levels ofslaughterhouse (45 samples) and retail stores (95 samples) full randomly. For the purpose of isolation, preT-KB Technique was used and, in order to identify, phenotyping tests were applied. Out of 140 testedsamples, 20 samples, at the rate of 14. 28%, were infected with the Arcobacter butzleri all of whichbelonged to the samples of hen meat. The highest rate of infection was observed in skin followed by thatin the abdominal contents and, finally, in the meat. Rate of frequency in the slaughter house samples was17. 77% and in the retail stores was 12. 63%. The poultries are considered as the main reservoir of theArcobacters. Presence of this bacterium in the poultry meat of the researched region can increaseprobability of transfer of this pathogenic agent to human through consumption of the feeding products. Thus, it appears that, in order to control infection with this bacterium in the cycle of production andconsumption of the poultry meat, it must be careful sufficiently.

Mentha spicata L. (Peppermint) is a widely used medicinal herb that also as a commonly herb spice hasused in the food industry. This study carried out to evaluating of chemical composition and antibacterialactivity of the essential oil of Mentha spicata L. (Peppermint) against Staphylococcus aureus andEscherichia coli. Essential oil of the herb leafs was extracted by Clevenger apparatus. Chemicalcomposition of essential oil was identified with a Gas chromatography/mass spectrometry system andthen Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of thisessential oil were determined using micro-dilution broth method in microplate 96 pits. A total of 33chemical constituents were identified which contained 98. 5% the total of essential oil compounds. Themost important components of this essential oil were: carvone (%28. 35), menthol (%14. 35), methylene(%14. 059) and limonene (%9. 303). MIC and MBC of essential oil of this herb against the S. aureus 25and 25 μ g/ml and against the E. coli was 50 and 100 μ g/ml respectively. Due to antibacterial compoundsof essential oil of this plant, it can be used as a natural preservative in food.

Staphylococcus aureus is able to produce several enterotoxins which can cause poisoning symptoms withdifferent intensities through eating of contaminated food. Due to the emergence of antibiotic-resistantstrains of S. aureus, the number of antibiotics available for treating these infections is reduced daily. Thisstudy aimed to isolate S. aureus and identification of methicillin-resistant gene in food samples usingPCR technique. The study included 320 samples of different foods were conducted between July of 2015and March of 2016. The samples were randomly collected from different parts of Mashhad, were sent tothe laboratory and in accordance with standard instructions were examined for the presence of S. aureus. The antibiotic sensitivity test was done by disk diffusion according to CLSI guidelines. PCR test was usedto identify and confirm the isolated S. aureus and Virulence genes and resistance. The result showed that53 samples (16. 6%) of the 320 samples were contaminated with S. aureus. The most contaminatedsample was sample sweet (19/7). Antibiogram results showed that the most sensitivity and the mostresistance to the antibiotic are for tobramycin antibiotics 100% tetracycline (15. 09%) respectively. isolates 9 (16. 98%) isolates of the 53 were resistant to methicillin in disk diffusion and 5 (9. 5%) isolateshad mecA resistance gene in PCR test. Due to high levels of Staphylococcus aureus food contaminationthe production and distribution of foods must be healthy controlled in order to prevent contamination andtransmission of resistant strains of these microbes.

Pigments produced by Monascus spp. can be used as food grade biocolorant and are preferredover the synthetic variants which elicit various adverse effects. Monascus purpureus PTCC 5303has been investigated in the present study for orang pigment production employing submergedfermentation. Central composite design (CCD) of response surface methodology (RSM) wasused to optimize the three significant medium components (date sugar concentration (20-60 g/l), salt (6-12%) and pH (6-9)). According to the response surface point prediction analysis, datesugar concentration of 20 g/l, NaCl 6% with 9 pH of medium could give maximum orangpigment yield up to 6. 7 OD. Under optimized experimental conditions, a maximum yield oforang pigment, biomass productivity, substrate conversion and productivity of orang pigmentproduction were 6. 24± 0. 05 (OD), 7. 2 (g/l), 82 (%) and 5. 36 (g/l. day), respectively. From theresults of this study, date waste can be used as a low cost substrate for the production of orangpigment in large scale studies.

Laccase have received much attention from researchers in last decades due to their ability tooxidase both phenolic and non-phenolic lignin related compounds as well as highly recalcitrantenvironmental pollutants, which makes them very useful for their application to severalbiotechnological processes. Despite of Trametes Laccase wildly application as detoxification ofindustrial effluents, its native low expression, makes it unsuitable for industrial application. In thisstudy, heterologous expression of Trametes Laccase gene in methylotrophic yeast, P. pastoris withα MF as signal peptide and Ppinkα HC expression vector under methanol induction in BMGY andBMMY media was investigated and expressed active recombinant laccase biochemical andbiophysical properties in compare with native Trametes Laccase was studied. According to codonperformance of P. pastoris, Trametes Laccase gene sequence designed and synthetic genes undercontrol of inducible AOX1 promoter was successfully high expressed as active form in yeast host, SDS-PAGE analysis showed the recombinant laccase in size of 65KDa with Km=140μ M. Analysisof Laccase biochemical and biophysical properties demonstrated that recombinant Laccase haswide pH profile with pH optima 4. 8 and optimum temperature of 60 ° C with high activity inP. pastoris host. We conclude that recombinant P. pastoris Laccase could fulfil a serried ofpredefined industrial quality criteria to be used in industry like, broad pH optimum, substratespecify and proper thermal stability. Therefore, studied methylotrophic yeast could be anappropriate host for expression and production of recombinant Laccase, with industrial application.

This study was conducted to investigate the effects of whey protein isolate with Lysozyme on the shelflifeof chicken fillets during refrigerated storage. Chicken fillets were treated in whey protein isolate andwhey protein isolate containing 0. 5, 1 % Lysozyme and compared with chicken fillets without anycoating (control) with 3 replicates were prepared. The microbial parameters (Total bacterial Mesophilic, Enterobacteriaceae, Psychrotroph and Pseudomonas spp count) were evaluated for 12 days. Resultsshowed that during the storage time, in the samples coated with whey protein isolate containing differentconcentration of Lysozyme, a significant reduction (p< 0. 05) were observed in the entire evaluatedmicroorganism groups compared to the control samples. Also a dose related trend was observed due toaddition of Lysozyme. Overall the findings of present study suggest that whey protein isolate containwith Lysozyme, may use as a natural coating and preservative to extend the chicken meat shelf life.

Staphylococcus aureus is a major opportunistic pathogen causing various diseases such aspneumonia and urinary tract infections. Indiscriminate and excessive use of antibiotics leads toantibiotic resistance in this bacterium, especially against commonly used antibiotics in thetreatment. The present study aimed to evaluate the antibiotic resistance pattern of Staphylococcusaureus strains isolated from milk and traditional milk products, especially resistance tomethicillin. A total of 403 samples of milk and milk products was examined and collected fromdistribution centers of traditional and dairy products. Strains isolated were tested by PCR todetermine the frequency of mec gene, SCCmec types and genes coding for antibiotic resistance. Antibiotic resistance pattern of isolates was assessed by disk diffusion method. Out of 403samples, 151 samples (%44. 67) were infected with Staphylococcus aureus, and the highestprevalence of infection was found in samples of cow raw milk (%58. 55). Only IV type wasdetected in mecA-positive isolates among SCCmec types; a number of 66 isolates belonged toIVd type, 21 isolates related to IVc type and 13 isolates belonged to IVa type and the significantdifferences between SCCmec type IVd with two types IVc and IVa was observed. The highprevalence of infection with Staphylococcus aureus in raw milk and traditional milk productsand high antibiotic resistance of the isolates to common types of antibiotics in treating humaninfections are serious warning to the community and it requires hygienic measures and qualitycontrol of dairy products more than ever.

Streptococcus iniae and lactococcus garviea are causative agents of Streptococcosis andLactococcosis respectively, diseases in fish. These diseases can be transmitted to humans by directcontact or consumption of infected fish. In recent years, these diseases had largely occured in fishfarms in Iran. The aim of this study was to evaluate the effect of lysozyme on S. iniae and L. garviea and also to determine MIC and MBC of different concentrations of lysozyme on thebacterial growth. Thus, antimicrobial effect of different concentrations of Lysozyme (19/53, 78/13, 89/06, 156/25, 312/5, 625, 1250, 2500 and 5000 μ g/ml) against S. iniae and L. garviea isolatedform rainbow trout in Chaharmahal and Bakhtiari province was investigated using thespectrophotometric and microdilution methods in three pH including: 5/5, 6 and 7. Results ofmicrodilution showed the inhibition of the growth of both bacteria effect by Lysozyms at pH=6and concentration of 5000 μ g/ml, whereas, at pH=7 was observed inhibition. Spectrophotometricmethod showed that the growths of both bacteria were decreased with increasing concentrationsof lysozyme in various pH. In comparison, the inhibition in Lysozyme concentration of 5000 μ g/mlat pH=6 and 5/5 was significantly lower that others (p<0/05). In conclusion, lysozyme wasinhibited the growth of S. iniae and L. garviea and also pH reducing had a significant effect on theantimicrobial activity of lysozyme.