Excess dietary iodine differentially affects thyroid gene expression in diabetes, thyroiditis-prone versus -resistant BioBreeding (BB) rats

Scope : To identify genes involved in the susceptibility to iodine‐induced autoimmune thyroiditis. Methods and results : Diabetes, thyroiditis‐prone (BBdp) and ‐resistant (BBc) rats were fed either a control or a high‐iodine diet for 9 wk. Excess iodine intake increased the incidence of insulitis and thyroiditis in BBdp rats. BBdp rats fed the high‐iodine diet that did not develop thyroiditis had higher mRNA levels of Fabp4, Cidec, perilipin, Pparγ and Slc36a2 than BBdp rats fed the control diet and BBc rats fed either the control or the high‐iodine diet. BBdp rats fed the high‐iodine diet that did develop thyroiditis had higher mRNA levels of Cidec, Icam1, Ifitm1, and Slpi than BBdp rats fed the control diet and BBc rats fed either the control or the high‐iodine diet. BBdp rats that did develop thyroiditis had lower mRNA levels of Fabp4, perilipin and Slc36a2 but higher mRNA levels of Icam1, Ifitm1 and Slpi than BBdp that did not develop thyroiditis. Excess dietary iodine also increased the protein levels of Fabp4, Cidec and perilipin in BBdp rats. Conclusion : Differential expression of thyroid genes in BBdp versus BBc rats caused by excess dietary iodine may be implicated in autoimmune thyroiditis and insulitis pathogenesis.     

Control of citrus green and blue molds by Chinese propolis

Green and blue molds, caused by Penicillium digitatum and Penicillium italicum, respectively, are economically important postharvest diseases of citrus fruits. In this study, Chinese propolis ethyl acetate extract (PEAE) was evaluated to control P. digitatum and P. italicum on postharvest citrus fruits. The results indicated PEAE strongly inhibited mycelia growth and induced hyphae prominent abnormal morphological alterations. Also, PEAE had strong detrimental effect on spore germination of the tested pathogens in a concentrationdependent manner. For in vivo tests, PEAE could both reduce decay caused by P. digitatum and P. italicum respectively in wound-inoculated fruit and naturally infected fruit; meanwhile, no negative influences on the overall quality of the citrus fruits were observed with PEAE treatment. Therefore, PEAE could be used as a natural antifungal agent to control citrus blue and green mold.     

The Brazilian Amazonian rainforest harbors a high diversity of yeasts associated with rotting wood,including many candidates for new yeast species

This study investigated the diversity of yeast species associated with rotting wood in Brazilian Amazonian rainforests. A total of 569 yeast strains were isolated from rotting wood samples collected in three Amazonian areas (Universidade Federal do Amazonas-Universidade Federal do Amazonas [UFAM], Piquiá, and Carú) in the municipality of Itacoatiara, Amazon state. The samples were cultured in yeast nitrogen base (YNB)-d -xylose, YNB-xylan, and sugarcane bagasse and corncob hemicellulosic hydrolysates (undiluted and diluted 1:2 and 1:5). Sugiyamaella was the most prevalent genus identified in this work, followed by Kazachstania. The most frequently isolated yeast species were Schwanniomyces polymorphus, Scheffersomyces amazonensis, and Wickerhamomyces sp., respectively. The alpha diversity analyses showed that the dryland forest of UFAM was the most diverse area, while the floodplain forest of Carú was the least. Additionally, the difference in diversity between UFAM and Carú was the highest among the comparisons. Thirty candidates for new yeast species were obtained, representing 36% of the species identified and totaling 101 isolates. Among them were species belonging to the clades Spathaspora, Scheffersomyces, and Sugiyamaella, which are recognized as genera with natural xylose-fermenting yeasts that are often studied for biotechnological and ecological purposes. The results of this work showed that rotting wood collected from the Amazonian rainforest is a tremendous source of diverse yeasts, including candidates for new species.     

Microbiology and foodborne pathogens in honey

Honey has been considered a relatively safe foodstuff due to its compositional properties, with infant botulism caused by Clostridium botulinum being the most prominent health risk associated with it. Our review is focused on the honey microflora along the food chain and evaluates the pathogenic potential of those microorganisms found in honey. This product may contain a great variety of bacteria and, particularly, fungi that eventually entered the food chain at an early stage (e.g., via pollen). For many of these microorganisms, opportunistic infections in humans have been recorded (e.g., infections by Staphylococcus spp., Citrobacter spp., Escherichia coli, Hafnia alvei, Aspergillus spp., Fusarium spp., Trichoderma spp., Chaetomium spp.), although direct infections via honey were not registered.     

Role of O-acetylhomoserine sulfhydrylase in sulfur amino acid synthesis in various yeasts

Mutants defective in O-acetylhomoserine sulfhydrylase (OAH-SHLase) were obtained in five yeast strains representative of different yeast genera: Saccharomyces cerevisiae, Kluyveromyces lactis, Yarrowia lipolytica, Schizosaccharomyces pombe and Trichosporon cutaneum. In vitro, in all five strains, the enzyme also had O-acetylserine (OAS) sulfhydrylase activity so it is a ‘bifunctional’ OAH/OAS-SHLase (Yamagata, 1989). The enzyme was only found to be essential in S. cerevisiae (OAH SHLase-negative mutants are auxotrophs). Its impairment in K. lactis caused a slower growth rate and a decrease of the sulfur amino acid pool. In T. cutaneum only the pool was affected whereas in Y. lipolytica and S. pombe the lesion caused no change in the growth rate nor in the pool. In all strains where OAH SHLase-negative mutants were prototrophs, a monofunctional OAS sulfhydrylase was detected. The results indicate that OAH SHLase may play different physiological roles in various yeasts.     

Genetically Similar Isolates of Salmonella enterica Serotype Enteritidis Persistent in China for a Long‐Term Period

Salmonella enterica serotype Enteritidis (S. Enteritidis) is an important causative agent of nontyphoidal salmonellosis in human populations. In this study, we collected 72 S. Enteritidis strains from 2004 to 2014 in Ningbo, mid‐east China. Of the 72 strains, we identified a dominant clone of 58 strains recovered from patient's feces (n = 48), blood (n = 1), pleural effusion (n = 1), chickens (n = 3), and dessert cakes (n = 5) by pulsed‐field gel electrophoresis (PFGE) and variable‐number of tandem repeat analysis (MLVA). The profile arrangements of MLVA were SE1‐SE2‐SE3‐SE5‐SE6‐SE8‐SE9: 4‐4‐3‐11‐10‐1‐3. These dominant strains were susceptible to ampicillin, chloramphenicol, tetracycline, ciprofloxacin, gentamicin, cefotaxime and trimethoprim–sulfamethoxazole, and resistant to nalidixic acid. Additionally, all isolates harboured virulence genes invA, sipA, sopE, and spvB when tested by PCR. Our results reveal that genetically similar S. Enteritidis strains which accounted for several outbreaks as well as blood infection and pleural cavity infection are prevalent in China for a long‐term period. This situation calls for further attention in the prevention and control of foodborne disease caused by Salmonella species.     

Microbial community changes in Makgeolli during brewing

Makgeolli, a traditional Korean alcoholic beverage, is produced from the simultaneous saccharification and fermentation of glutinous rice by microbes introduced through nuruk (fermentation starter). The microbial community in Makgeolli is complex, and changes in the community are important for quality control and product development of Makgeolli. In this study, changes in the microbial community of Makgeolli during brewing were monitored by pyrosequencing. Pyrosequencing of microbes in Makgeolli illustrated dynamic changes in the populations and species of bacteria and fungi during brewing. Saccharomyces, a fungal genus, dominated the fungal community in Makgeolli throughout brewing, and produced alcohol after sufficient production of reducing sugars. As the bacterial genera Pediococcus, Weissella, Lactobacillus and Enterococcus, categorized as lactic acid bacteria, grew in Makgeolli, the pH decreased. The fungal community in Makgeolli was not significantly changed during brewing, but there were dynamic changes in the bacterial community, especially during the first 2 days of brewing. Copyright © 2015 The Institute of Brewing & Distilling     

Listeria monocytogenes in retail establishments: Contamination routes and control strategies

In the past two decades, serious outbreaks of foodborne disease were caused by Listeria monocytogenes, a pathogen frequently found in delicatessens at retail. Although the prevalence of listeriosis is not high, the severity of disease is significant, with high hospitalization and mortality rates. Potential sources of L. monocytogenes and food contamination routes in retail and food service operations include incoming raw materials, food products, food handlers, customers, vendors, and environmental sources. Risk mitigation strategies for L. monocytogenes should be based on integrated control along the food chain continuum, from farm to retail establishment.     

Impairment of Peroxisome Degradation in Pichia methanolica Mutants Defective in Acetyl-CoA Synthetase or Isocitrate Lyase

Single recessive mutations of the methylotrophic yeast Pichia methanolica acs1, acs2, acs3 and icl1 affecting acetyl-CoA synthetase and isocitrate lyase, and growth on ethanol as sole carbon and energy source, caused a defect in autophagic peroxisome degradation during exposure of methanol-grown cells to ethanol. As a control, a mutation in mdd1, which resulted in a defect of the ‘malic’ enzyme and also prevented ethanol utilization, did not prevent peroxisome degradation. Peroxisome degradation in glucose medium was unimpaired in all strains tested. Addition of ethanol to methanol-grown cells of acs1, acs2, acs3 and icl1 mutants led to an increase in average vacuole size. Thickening of peroxisomal membranes and tight contacts between groups of peroxisomes and vacuoles were rarely observed. These processes proceeded much more slowly than in wild-type or mdd1 mutant cells incubated under similar conditions. No peroxisomal remnants were observed inside vacuoles in the cells of acs1, acs2, acs3 and icl1 mutants after prolonged cultivation in ethanol medium. We hypothesize that the acs and icl mutants are defective in synthesis of the true effector—presumably glyoxylate—of peroxisome degradation in ethanol medium. Lack of the effector suspends peroxisome degradation at an early stage, namely signal transduction or peroxisome/vacuole recognition. Finally, these defects in peroxisome degradation resulted in mutant cells retaining high levels of alcohol oxidase which further led to increased levels of acetaldehyde accumulation upon incubation of mutant cells with ethanol. © 1997 by John Wiley & Sons, Ltd.     

Evaluation of plant oils for suppression of crown rot disease and improvement of shelf life of banana (Musa spp. AAA subgroup,cv. Robusta)

Fourteen plant oils were evaluated to control the crown rot disease caused by Lasiodiplodia theobromae and Colletotrichum musae. Five of these, viz. Ocimum sanctum, Cymbopogan citratus, C. martinii, C. nardus and Pelargonium graveolens oils completely arrested the mycelial growth of both test pathogens at their lowest concentration compared to other oils. Besides, these plant oils have also inhibited the activity of cellulolytic and pectinolytic enzymes produced by these pathogens effectively under in vitro condition. The treatment of banana fruit var. Robusta (Cavendish‐AAA) with oils of O. sanctum, C. citratus, C. nardus and C. martinii not only reduced the crown rot severity significantly, but also increased the shelf life of banana fruits. However, under low‐temperature storage (14 °C) condition, O. sanctum oil increased the shelf life of banana fruits up to 48 days without affecting their organoleptic properties. Hence, O. sanctum oil could be used as an alternative to chemical fungicides for the management of crown rot disease.     

湘味卤豆干中腐败微生物的分离鉴定及控制

目的：更好地控制湘味卤豆干腐败微生物的生长,保证湘味卤豆干的食品安全。方法：采用平板划线法进行初筛,结合菌落形态观察、革兰氏染色、16S rDNA和ITS序列鉴定湘味卤豆干中的腐败微生物。结果：共分离筛选得到9株菌株,KZ2780-3和KZ2780-4为枯草芽孢杆菌（Bacillus subtilis）、NZ2559-1为蜡样芽孢杆菌（Bacillus cereus）、JZ2559-5为解淀粉芽孢杆菌（Bacillus amyloliquefaciens）、FZ2559-2为肺炎克雷伯氏菌（Klebsiella pneumoniae）、SZ2641-5为屎肠球菌（Enterococcus faecium）、RZ2641-7为溶血性葡萄球菌（Staphylococcus haemolyticus）、BZ2780-1为鲍氏不动杆菌（Acinetobacter baui）、CZ2780-5为橘青霉（Penicillium citri）。结论：引起湘味卤豆干腐败的菌株是枯草芽孢杆菌、蜡样芽孢杆菌、解淀粉芽孢杆菌、肺炎克雷伯氏菌、屎肠球菌、溶血性葡萄球菌、鲍氏不动杆菌、橘青霉。湘味卤豆干的控制方法是超高温瞬时杀菌技术、等离子体杀菌技术、天然抑菌物质结合生物防腐剂、真空包装、气调保鲜等。     

Synergistic effect of oligochitosan and silicon on inhibition of Monilinia fructicola infections

BACKGROUND: Oligochitosan has broad‐spectrum antimicrobial activity and shows an obvious inhibitory effect on phytopathogens. In addition, as an exogenous elicitor, it can induce various defence responses, including affecting the activities of several defence‐related enzymes and substances in some plants. Owing to this dual function of oligochitosan, it can be used to control postharvest diseases of fruits. Silicon, like oligochitosan, also has a dual function. In this study the synergistic effect of oligochitosan and silicon on the decay control of apple fruit was investigated. RESULTS: In vitro, both oligochitosan and silicon significantly inhibited spore germination, germ tube elongation and mycelial growth of Monilinia fructicola, with higher concentrations having a greater effect. The synergistic effect of oligochitosan and silicon at half‐maximal inhibitory concentration on disease control at 25 °C was much better than the effect of oligochitosan or silicon alone, not only in vitro but also in vivo. CONCLUSION: The results showed that a combination of oligochitosan and silicon had a synergistic effect on the control of disease caused by M. fructicola in apple fruit at 25 °C. Copyright © 2010 Society of Chemical Industry     

Combination of ultraviolet light-C and clove essential oil to inactivate Salmonella Typhimurium biofilms on stainless steel

Salmonella typhimurium is able to form biofilms as a resistance mechanism against antimicrobials; therefore, it represents a problem for assuring food safety and highlights the importance of research on anti-biofilm technologies. In this study, S. typhimurium biofilms were inactivated with the combination of clove essential oil (CEO) and ultraviolet light (UV-C). The volatile composition of the CEO determined by gas chromatography showed eugenol as the major constituent (82%). A combination of CEO with UV-C achieved a complete bacterial reduction (6.8 log/cm²) on biofilms with doses of 1.2 mg/ml and 76.41 mJ/cm², respectively. Individually, the CEO at 1.2 mg/ml caused a reduction of 1.8 log CFU/cm² of attached bacteria cells on stainless steel, while UV-C individually used at 620.4 mJ/cm² caused a 2.9 log CFU/cm² reduction compared to control biofilms. In conclusion, this study demonstrated a synergistic effect of combining CEO and UV-C irradiation to inactivate biofilms of S. typhimurium.     

Real-time-PCR-System zum Nachweis von Bacillus cereus (emetischer Typ) in Lebensmitteln

Bacillus cereus is a Gram-positive, facultative anaerobic, spore-performing bacterium. Some B. cereus strains have the ability to produce two different types of toxins: (a) diarrhoeic toxin: the disease is similar to a C. perfringens toxin-infection; it is caused by a heat-labile protein, (b) emetic toxin: the disease is similar to Staphylococcus-aureus intoxikation; it is caused by a heat-stable protein. Statements about the frequency of B. cereusfood-poisonings are difficult because a reporting system for this disease is missing in Germany and there exists no valid methodology to diagnose this disease with conventional microbiological or biochemical methods. Nevertheless B. cereus, beside S. aureus, seems to be the most important bacterium to cause food-associated intoxications.     

The effects of brine concentration and scalding on survival of some pathogens in urfa cheese: a traditional white-brined turkish cheese

The survival of Staphylococcus aureus (St. aureus), Bacillus cereus, Yersinia enterocolitica, Eschericia coli O157:H7, Shigella flexneri (Sh. flexneri) and Salmonella enteritidis (Sa. enteritidis) in urfa cheese (a traditional white‐brined Turkish cheese) which was stored in brine concentrations varying from 12.5 to 17.5% (wt/v) was tested. Two sets of cheeses were made, namely scalded and unscalded cheeses (scalding was done by heating at 95 °C for 3 min). The variations in the counts of pathogenic colonies were monitored throughout a 90‐day storage period at <10 °C. Results indicated that scalding caused statistically significant reductions in the colony counts of Y. enterocolitica, E. coli O157:H7, Sh. flexneri and Sa. enteritidis during the early periods of storage. In contrast, St. aureus and B. cereus were not generally affected by scalding and brine concentrations, although B. cereus in 17.5% (wt/v) brine was affected. In the unscalded cheeses, 12.5 and 15.0% (wt/v) brine concentrations seemed to be insufficient to eradicate the pathogenic organisms examined.     

Current and future interventions for improving poultry health and poultry food safety and security: A comprehensive review

Poultry is thriving across the globe. Chicken meat is the most preferred poultry worldwide, and its popularity is increasing. However, poultry also threatens human hygiene, especially as a fomite of infectious diseases caused by the major foodborne pathogens (Campylobacter, Salmonella, and Listeria). Preventing pathogenic bacterial biofilm is crucial in the chicken industry due to increasing food safety hazards caused by recurring contamination and the rapid degradation of meat, as well as the increased resistance of bacteria to cleaning and disinfection procedures commonly used in chicken processing plants. To address this, various innovative and promising strategies to combat bacterial resistance and biofilm are emerging to improve food safety and quality and extend shelf-life. In particular, natural compounds are attractive because of their potential antimicrobial activities. Natural compounds can also boost the immune system and improve poultry health and performance. In addition to phytochemicals, bacteriophages, nanoparticles, coatings, enzymes, and probiotics represent unique and environmentally friendly strategies in the poultry processing industry to prevent foodborne pathogens from reaching the consumer. Lactoferrin, bacteriocin, antimicrobial peptides, cell-free supernatants, and biosurfactants are also of considerable interest for their prospective application as natural antimicrobials for improving the safety of raw poultry meat. This review aims to describe the feasibility of these proposed strategies and provide an overview of recent published evidences to control microorganisms in the poultry industry, considering the human health, food safety, and economic aspects of poultry production.     

High-pressure-induced changes in the characteristics of low-fat and high-fat sausages

The purpose of this study was to analyse the consequences of applying high pressures (100 and 300 MPa for 5 and 20 min) on characteristics such as water and fat binding properties, texture, colour, microstructure and microbiology of low-fat (90 g kg⁻¹, LF) and high-fat (247 g kg⁻¹, HF) meat emulsions. Pressurising of LF and HF samples at 300 MPa caused a decline (P<0·05) in emulsion stability, which was more pronounced at the higher pressure. The influence of high pressures on emulsion texture varies according to fat content. In HF samples, high pressure caused a decrease (P<0·05) in Kramer shear force and Kramer energy, regardless of pressure intensity or time. Pressurisation generally caused increase (P<0·05) in the colour lightness parameter in sausages; the effect on redness and yellowness, however, was dependent on fat content, pressure intensity and pressure time. © 1997 SCI.     

Lactic Fermentation Effects on Preservative Qualities of Dendeng Giling

Model “Dendeng giling”, Indonesian non fermented dried beef, was prepared after fermentation with Lactobacillus plantarum as starter and compared with control without starter culture. Inoculated sample was fermented at 30°C 16 hr, Lactobacillus grew from 10⁶ to 10⁸, pH went from 5.71 to 5.2. Micrococcus, Gram-negative bacteria, Pseudomonas, Staphylococcus, and Escherichia coli were inhibited by 98.3%, 77%, 93%, 96% and 77% after fermentation 16 hr. Inoculated samples were tested for inhibiting VBN and TBA value, dissipating residual nitrite and development of redness. Lower pH caused faster drying at 50°C and reduced water activity. The combination of low pH and water activity made possible improvement of preservative quality.