Antimicrobial Resistance,Virulence Profile,and Molecular Characterization of Listeria monocytogenes Isolated from Ready-to-eat Food in China,2013-2014

We aimed to investigate the potential pathogenic profile and antibiotic resistance of Listeria monocytogenes isolated from ready-to-eat food in China.Antimicrobial resistance was determined by broth microdilution following the Clinical and Laboratory Standards Institute protocol Molecular serotyping,virulence,and resistance genes were identified using PCR.Multi-locus

Antimicrobial Profile of Lactic Acid Bacteria Isolated from Vegetables and Indigenous Fermented Foods of India against Clinical Pathogens Using Microdilution Method

In dairy and food industries lactic acid bacteria （LAB） have been used in form of starter culture that plays vital role in fermentation; as flavouring and texturizing or as preservative agents. There is increasing evidence that lactobacilli which inhabit the gastrointestinal tract develop antimicrobial activities and participate in the host＇s defence system[1]. During fermentation, most of the LAB produces a number of different compounds like organic acids, hydrogen peroxide, diacetyl, acetaldehyde, carbon dioxide, polysaccharides, and proteinaceous compounds called bacteriocins or bacteriocinogenic peptides.

Development of African Earthenware Container Imbedded with Nanosilver Particles for Food Preservation

With the aim of ameliorating its preservation capacity, silver nanoparticles (0 - 100nm) with 99.9% purity and 35nm average particle size, were used as building material for earthenware jar, an extremely old container which is still used in rural African villages specifically in North Cameroon. Earth material was dissolved in water at the weight ratio of 5% to 10%. Silver nanoparticles were then added to the mixture and stirred to prepare 1% to 5% Ag/Earth paste (1 to 5 ppm). A grounded metal rotating drum was used to prepare earth embedded nanosilver plates. An n-order mathematic expression was used to evaluate the shelf-live quality and deterioration rate of sorghum porridge preserved in this African earthenware container imbedded with nanosilver particles. Accelerated shelf-life testing was used to predict the shelf life of the product at usual rural storage conditions. The used Arrhenius model indicated that the shelf life of the sorghum porridge stored in African earthenware container imbedded with nanosilver particles can be extended to 14 days at 4&degC ± 1&degC, 6 days at 15&degC ± 5&degC, and 4 days at 30&degC ± 2&degC. The calculated Q10 values were found to be in the range of 1.5 - 2.0.

Role of essential oils in food safety: Antimicrobial and antioxidant applications

Essential oils(EOs)are more complex and comprise a number of volatile and natural bioactive compounds,which often used in food industries as the best alternatives.This review focuses on the impact of EOs and the roles of their major components in food manufacturing as natural preservatives with the related mechanisms of action.In addition,the major bioactive molecules of different types of EOs and their pharmacological activities such as antioxidant,antifungal and antimicrobial effects on crop protection were also discussed.The major compounds of EOs represent potential antioxidant,antimicrobial and antifungal activities through various mechanisms.Different types of EOs such as tea tree oil,lemon oil,clove oil,cinnamon oil and thyme oil from various traditional plants,have significantly showed better antimicrobial and antioxidant activities,and also effectively increased the shelf lives of the cereal products and increased the quality of food safety.The major groups of EOs such as terpenes and aromatic volatile compounds,play a key role in food safety without affecting the quality.Due to their various activities including antioxidant and antimicrobial activities,EOs could be used as alternative preservatives to increase the shelf lives of cereals and crops.

Synergism of essential oils with lipid based nanocarriers: emerging trends in preservation of grains and related food products

Grains are one of the major food staples in the world.The cereal grains are easily susceptible to damage by moisture content,flour beetles and food pathogens during storage,harvesting and post harvesting.Food preservative techniques namely drying,freezing,and dehydration,acquire little advantages.However,they cause few undesirable alterations in the organoleptic and nutritional properties of the preserved food items.Therefore,there is a continuous search for new preservation techniques in food industries,to satisfy the customer demands on the addition of natural food preservatives,devoid of pathogenic contaminants and without changes in organoleptic properties.Essential oils(EOs)have been predicted as“natural food additives”in the preservative process.The synergistic potential of EOs with various nanocarriers plays an emerging role in the food industry.Therefore,the present review has focused on the lipid based nanocarriers,and the methods used for the functionalization or encapsulation of EOs and applications in the preservation of food items such as cooked rice,rice flour,grains,sliced breads have also been discussed.The present review ascertains the antimicrobial significance of active EOs loaded lipid nanocarriers in the form of nano emulsions,solid lipid nanoparticles and liposomes for preserving grains and flours.

Use of ultrasound in food preservation

Ultrasound is versatile and innovative technology due to its wide range of application and increase in knowledge and research studies. It is used in food industry for many purposes including analysis methods and food processings such as freezing, cutting, drying, tempering, homogenization, degassing, antifoaming, filtration and extraction. Ultrasound can be used as a promoter or alternative to food processing. There may be numereous advantages of using ultrasound for food processing such as effective mixing, increased mass transfer, reduced energy, reduced temperature and increased production rate. Due to the elimination of microorganisms and enzymes without destroying nutrients of foods, ultrasound can be used as an alternative method to thermal treatments in the food preservation. Additionally, low power ultrasound is thought to be an attractive nonthermal method due to overcome problems which occur during heat treatments such as physical and chemical changes, nutritional loss and change in organoleptic properties. This review summarizes mechanism, operation and latest potential applications of ultrasound in the food preservation.

Characterization of Natural Antimicrobials in Food System

There has been a rising interest in using natural antimicrobial compounds in food industry due to current trend of giving value to natural and renewable resources. These antimicrobials provide new modalities to ensure microbial safety and extend the shelf-life of foodstuffs. Natural antimicrobials can be directly added into the food, but several efforts have been made to find alternative solutions to the aim of avoiding undesirable inactivation. Some different ways such as, dipping, spraying, and coating treatment of food are currently applied to product before packaging considered as valid options. The present paper aims to review the use of natural compounds to control microbiological and physicochemical shelf life of major food categories such as, meat, fish, dairy-based products, fruit and vegetables, and cereal-based products.

Application of Selected Natural Antimicrobial Formulations for the Control of Food Pathogens in Fresh-Cut Cauliflower

In recent years, research on biopolymer based-coating containing natural antimicrobial agents is developing significantly. The objective of this study was to evaluate the antimicrobial efficiency of six formulations containing pre-selected natural antimicrobial compounds against Listeria monocytogenes, Escherichia coli O 157：H7, Salmonella typhimurium, the total bacteria and total yeasts and molds in cauliflower. Each formulation was subjected to a sensory test in parallel to microbiological analysis and the efficiency during storage at 5 ℃ was evaluated for the two best formulations, based on their ability to eliminate the target microorganisms. Both formulations were able to reduce all pathogens and total flora below detectable levels after 24 h of storage at 5 ℃. Using washing or spraying treatments, the two formulations were able to reduce Listeria to undetectable levels for 3 d. This efficiency was extended to 7 d when the formulations were incorporated into an edible coating. Washing treatment with the two formulations was also able to limit the growth of yeast and molds at levels lower than 2 log, for more than 7 d. The population of E. coli was reduced to below the detection limit during 14 d of storage, after washing treatment with the two formulations. The spraying treatment of cauliflower with the formulations allowed the use of very small amounts of antimicrobials while maintaining a fairly good efficiency, greatly reducing the potential costs of implementing this method in the industry. Future research may focus on development of nanoemulsion of antimicrobial formulations based on the developed antimicrobial formulations in this study to improve the better coating efficiency.

Food Safety and Antimicrobial Resistance an Approach to the Genus <i>Salmonella</i>spp.

Foodborne Illnesses (FI) are considered an important problem in public health for their high levels of morbidity and, in some cases, of mortality in Mexico and around the world. Different agents that cause Foodborne Illnesses, in which biological agents such as the genus Salmonella spp., are included, have been often associated with outbreaks. A continued effort has been observed in the food industry, in collaboration with sanitary authorities on a global scale, through the creation and continued improvement of different procedures to prevent the contamination by Salmonella, in which the elaboration of laboratory methodologies for the detection and isolation of this pathogen in foods and, in such manner, prevents the outbreak of illnesses. However, along with the aforementioned, it has been reported that a few years ago, the appearance of an ever-increasing number of strains of Salmonella spp., in foods with multi-drug resistance to antibiotics which are used in the treatment of its illness, results in a major emphasis on the health issue related to Foodborne Illnesses and, in particular, to those generated by factors of medical dependence such as the increase in recuperation time, costs, and reduction in the number of alternative pharmaceutical treatments. This work presents a general overview of FI, in which illnesses generated by bacteria of the genus Salmonella spp., their detection in a microbiological laboratory, as well as the phenomenon of resistance to antibiotics by these bacteria, and the current and difficult issue reported through different investigations all around the world, of the rise in this phenomenon and its importance in public health, are discussed.

Genotypic Characterization of Methicillin-resistant Staphylococcus aureus Isolated from Pigs and Retail Foods in China

Objective To investigate the genotypic diversity of Methicillin-resistant Staphylococcus aureus （MRSA） isolated from pigs and retail foods from different geographical areas in China and further to study the routes and rates of transmission of this pathogen from animals to food. Methods Seventy-one MRSA isolates were obtained from pigs and retail foods and then characterized by multi-locus sequencing typing （MLST）, spa typing, multiple-locus variable number of tandem repeat analysis （MLVA）, pulsed-field gel electrophoresis （PFGE）, and antimicrobial susceptibility testing. Results All isolated MRSA exhibited multi-drug resistance （MDR）. Greater diversity was found in food-associated MRSA （7 STs, 8 spa types, and 10 MLVA patterns） compared to pig-associated MRSA （3 STs, 1 spa type, and 6 MLVA patterns）. PFGE patterns were more diverse for pig-associated MRSA than those of food-associated isolates （40 vs. 11 pulse types）. Among the pig-associated isolates, CC9-ST9-t899-MC2236 was the most prevalent clone （96.4%）, and CC9-ST9-t437-MC621 （20.0%） was the predominant clone among the food-associated isolates. The CC9-ST9 isolates showed significantly higher antimicrobial resistance than other clones. Interestingly, CC398-ST398-t034 clone was identified from both pig- and food-associated isolates. Of note, some community- and hospital-associated MRSA strains （t030, t172, t1244, and t4549） were also identified as food-associated isolates. Conclusion CC9-ST9-t899-MC2236-MDR was the most predominant clone in pigs, but significant genetic diversity was observed in food-associated MRSA. Our results demonstrate the great need for improved surveillance of MRSA in livestock and food and effective prevention strategies to limit MDR-MRSA infections in China.

Research progress of plant antimicrobial peptides

Plant antimicrobial peptides are a very large family of antimicrobial peptides,which have strong resistance to various pathogenic microorganisms,especially fungi.With the increasing use of antibiotics,the problems caused by antibiotics,including antibiotic residues and pathogen resistance,are becoming more and more prominent.The research on antimicrobial peptides as new antibiotic substitutes is also a hot spot.This article introduces the action sites and antibacterial mechanisms of several plant antimicrobial peptides,as well as the application of plant antimicrobial peptides in the fields of medicine,agriculture,and food preservation.

Antimicrobial use in food animal production:situation analysis and contributing factors

By measuring the quantity and ways in which antimicrobials are used, and reviewing different technical and socioeconomic factors influencing antimicrobial use at farm level, this study discusses the main knowledge gaps in antimicrobial use in food animal production and provides recommendations for future research and policy development. The review reveals that antimicrobial use in food animals exhibit strong regional and species differences, and there are still large information gaps concerning the current state of antimicrobial use. Factors associated with animal health(including antimicrobial resistance),animal health improvement, economic costs and benefits relevant to animal diseases, and potential technological alternatives or alternative systems all have an impact on antimicrobial use on the farm. There is a clear need to resolve the data gap by monitoring antimicrobial use and developing an analytical framework to better understand farmer behaviors under different technical, economic and environmental circumstances.

The health benefits of selenium in food animals:a review

Selenium is an essential trace mineral important for the maintenance of homeostasis in animals and humans.It evinces a strong antioxidant,anti-inflammatory and potential antimicrobial capacity.Selenium biological function is primarily achieved by its presence in selenoproteins as a form of selenocysteine.Selenium deficiency may result in an array of health disorders,affecting many organs and systems;to prevent this,dietary supplementation,mainly in the forms of organic(i.e.,selenomethionine and selenocysteine)inorganic(i.e.,selenate and selenite)sources is used.In pigs as well as other food animals,dietary selenium supplementation has been used for improving growth performance,immune function,and meat quality.A substantial body of knowledge demonstrates that dietary selenium supplementation is positively associated with overall animal health especially due to its immunomodulatory activity and protection from oxidative damage.Selenium also possesses potential antiviral activity and this is achieved by protecting immune cells against oxidative damage and decreasing viral replication.In this review we endeavor to combine established and novel knowledge on the beneficial effects of dietary selenium supplementation,its antioxidant and immunomodulatory actions,and the putative antimicrobial effect thereof.Furthermore,our review demonstrates the gaps in knowledge pertaining to the use of selenium as an antiviral,underscoring the need for further in vivo and in vitro studies,particularly in pigs.

Use of antimicrobials in food animals and impact of transmission of antimicrobial resistance on humans

Antimicrobial resistance leads to failure of clinical antimicrobial therapy,and has raised urgent global public health concern.Humans can acquire antimicrobial resistance fromdrugs through the food chain or the environment(contaminated water,air,soil,or manure).While antimicrobials have been regular supplements in animal feed that maintain health and improve productivity of livestock,their over-use in feeding forage has led to a rise in antibacterial resistance.This review summarizes the current use of antimicrobials in livestock,the harmful effects of antimicrobial resistance,and the comprehensive combat measures.

Enhancement and Preservation of Fresh Orange Juice Using Citrus Essential Oils

Nowadays, consumers are demanding for minimally processed, additive-free, high quality, fresh-like andmicrobiologically safe foods. However, as food deterioration is the constant threat along the entire food chain, food preservationremains as necessary today as in the past. In this paper, several citrus essential oils, including sweet orange, lemon and lime essentialoil applied directly in fresh orange juice as a natural preservative, were analyzed for their antimicrobial activity. The antimicrobialactivity of each citrus essential oil was assessed against Saccharomyces cerevisiae, Lactobacillus plantarum and Aspergillus nigerusing broth macrodilution. Among all citrus essential oils tested, sweet orange essential oil with 0.10% concentration showedsignificant antimicrobial activity against microorganisms tested. Hence, it was chosen to be applied in the fresh orange juice. Then,shelf life analysis was conducted during 7 d of storage at 5 ℃ and during 2 d of storage at 25 ℃ using selected concentration of theselected citrus essential oil in the fresh orange juice. Based on the results obtained, the addition of sweet orange essential oil with0.10% concentration was not able to prolong the shelf life of the fresh orange juice according to the Indonesian National Standard（SNI）. However, the formulation of fresh orange juice itself was able to improve its shelf life when compared to the shelf life of thecommercial orange juice.

The interaction of nanostructured antimicrobials with biological systems:Cellular uptake,trafficking and potential toxicity

Nanomaterials have been found increasing applications in the food sector.Nanostructured antimicrobials can be incorporated either to food matrix of food packaging or to provide extended safety and quality.However,the interactions and effects of nanomaterials with biological systems are still poorly understood.Nanoparticles can enter the organism by oral,dermal and inhalation routes and distributed to different tissues by the circulatory system.Increasing evidence indicate that targeting to specific tissues,cellular uptake and intracellular fate of nanoparticles are strongly influenced by size,shape and surface properties.The specific characteristics of nanomaterials are also determinant for their toxicity in higher organisms.The dose,exposure time and administration route are important aspects influencing toxicity of nanoparticles as well.Both in vitro and in vivo evaluation studies on different types of nanostructures have providing information to support a better understanding about the interactions of nanoscale materials with biological systems.

Bio-control of Some Food-Borne Pathogenic Bacteria by Bacteriophage

In recent years, researchers tended to bring new alternative to biological protective systems used in conservation of food and production of safe food. Use of bacteriophage against to pathogen bacteria in food was the most hopeful system in these methods about bio-control. Controls of bacteriophage for each pathogen species and subspecies and determination of phage-host originality are important because efficient bio-control was achieved. Researches concentrated on some food-borne pathogen bacteria such as E. coli O157：H7, Campylobacter, Salmonella and Listeria. In a consequence of these studies made as in vitro and in vivo, first commercial production of phage which will be used in foods was made in Netherlands. Also, it has been informed that use of phage is cost-efficient alternative as compared with other preservatives. This review, discussed application of bacteriophages as bio-control agents in food and advantages and disadvantages about uses of bacteriophages by taking into account antimicrobial characteristics of them.

Antimicrobial Resistance in <i>Enterococcus</i>sp Isolated from Soft Cheese in Southern Brazil

The aim of this research was to study the incidence of antibiotic resistance in 56 Enterococcus strains isolated from dairy products. The identification of enterococci was detected by polymerase chain reaction (PCR) using specific primers to E. faecalis, E. faecium, E. gallinarum and E. casseliflavus, and antibiotic resistance was tested by the disk diffusion method. The most prevalent species was E. faecium with a rate of 58.33%, followed by 27.77% E. faecalis, 11.11% E. casseliflavus and 2.7% E. gallinarum. Distribution of resistance was found in different species. All isolates were susceptible to chloramphenicol, ampicillin, imipenem and amoxicillin/clavulanic acid. In addition, isolates resistant to tetracyclin, nalidixic acid, amikacin, erythromycin, vancomycin and cephalothin were detected. A total of 66.6% of E. faecium and 58.3% of E. faecalis strain were resistant to multiple drugs. The van(A) gene was detected in 100% of vancomycin resistant enterococci. Considering the results of our study, dairy enterococci can be considered a potential source for dissemination of antibiotic resistances.

The Use of Zinc Oxide Nanoparticles in Eva to Obtain Food Packing Films

The increasing demand for new packages with increased shelf life properties has stimulated the increase of research in the active packaging sector. The use of antimicrobial agents requires an in-depth study of their properties to avoid loss of efficiency of the polymer processing. In this context, the objective of this work was to evaluate the preparation of an 18% ethylene vinyl acetate copolymer (EVA) nanocomposite and zinc oxide (ZnO) as microbicidal nanoparticle, prepared in a monosulfon extruder. The nanoparticle was modified with octadecylamine and EVA 18 nanocomposite films were prepared and compared to the systems containing modified nanoparticle. These new materials were characterized by thermogravimetric analysis (TGA), Differential Scanning Calorimetry (DSC), X-Ray Diffraction (XRD), Dynamic Mechanical Analysis (DMA), Time Domain Nuclear Magnetic Resonance (NMR) to investigate the effect of zinc oxide nanoparticles on thermal properties, EVA crystallinity and antimicrobial effect. The TGA showed a tendency of increase of the thermal stability in different proportions of ZnO. DSC results did not show significant changes in thermal parameters. The XRD analysis showed an increase in the degree of crystallinity of the nanocomposites in relation to the EVA matrix and change in the crystallinity with the increase of ZnO percentages. DMA analysis indicates change in structural organization through the variation of storage modulus, loss, and tan delta. Time domain NMR data corroborate with XRD data through the change in molecular mobility.

Antimicrobial Effect of Skin for Allograft and Management in Burn Wound

One of the most important functions of skins is to protect our bodies from microbes or pollutant sources. Skins containing physical substances serve as a physical barrier which protects our bodies from pathogens. A healthy skin contains a variety of antibacterial substances such as defensin, cathelicidin and psoriasin. However deep and wide burns cause the skin to lose its original functions, so our skins are exposed to various danger factors. For the burn patients, human alloskin graft serves as a very important temporary biological wound dressing. It protects the wound before autograft procedure, forms revascularization and granulation tissues and protects the wound from an invasion of microbes. This study was conducted with the aim to analyze the antimicrobial effect of cryopreserved allograft (CPA) and glycerol-preserved allograft (GPA) which was a type of allograft widely used for burn patients, and measure the difference in comparison with the fresh skin before processing it. The most common contaminants found in burn patients such as S. aureus, P. aeruginosa, C. albicans and E. coli, were used for experiment. The antimicrobial effect against S. aureus and E. coli was observed in fresh skin and some CPA. In some clinical cases, infection is frequently observed in the wounds treated with allograft, indicating the allograft completely block every kind of microbes. To prevent the infection, it is required to use antibiotics and manage wounds thoroughly.