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 Activity of Wild Plant Seed Extracts against Human Bacterial and Plant Fungal Pathogens

Five wild plant species belonging to different families (Chenopodium album, Plantago major, Elytrigia elongata, Filipendula ulmaria and Nigella sativa) widely spread in Russian Federation and the former USSR were evaluated for their ability to inhibit growth of two important human food-borne pathogens (Escherichia coli O157:H7 and Listeria monocytogenes strain EGD-e) and eight plant pathogens (Alternaria alternata, Alternaria tenuissima, Bipolaris sorokiniana, Stagonospora nodorum, Fusarium solani, Fusarium oxysporum, Fusarium culmorum and Phytophtora infestans). To isolate biologically active compounds from seeds, a step-wise procedure including extraction with hexane, ethyl acetate, ethanol, and 10% acetic acid followed by reversed-phase HPLC was developed. Using disc-diffusion assay, the highest activity against E. coli O157:H7 was observed with extracts from F. ulmaria (hexane and ethyl acetate extracts and the unbound RP-HPLC fraction) and P. major (ethyl acetate extract and the unbound RP-HPLC fraction);E. elongate (the unbound RP-HPLC fraction) was less active. The extracts from P. major and E. elongate (the unbound RP-HPLC fractions) were equally highly active against L. monocytogenes, while those of F. ulmaria (the unbound RP-HPLC fraction) and N. sativa (hexane and ethyl acetate extracts) were less active against this pathogen. The dynamics of L. monocytogenes EGD-е and E. coli O157:H7 growth in the presence of two most potent extracts (RP-HPLC-unbound fractions of P. major and E. elongate and the hexane extract of F. ulmaria) was studied.

Antibacterial activity of leaves extracts of Trifolium alexandrinum Linn,against pathogenic bacteria causing tropical diseases

Objective:To investigate antibacterial potential of Trifolium alexandrinum(T.alexandrinum) Linn,against seven gram positive and eleven gram negative hospital isolated human pathogenic bacterial strains responsible for many tropical diseases.Methods:Non-polar and polar extracts of the leaves of T.alexandrinum i.e.,hexane,dichloromethane(DCM),ethyl acetate(EtOAc), methanol(MeOH) and aqueous(AQ) extracts at five different concentrations(1,2,5,10 and 15 mg/ mL) were prepared to evaluate their antibacterial value.NCCL standards were strictly followed to perform antimicrobial disc susceptibility test using disc diffusion method.Results:Polar extracts demonstrated significant antibacterial activity against tested pathogens.EtOAc and MeOH extracts showed maximum antibacterial activity with higher inhibition zone and were found effective against seventeen of the tested pathogens.While AQ plant extract inhibited the growth of sixteen of the test strains.EtOAc and MeOH plant extracts inhibited the growth of all seven gram positive and ten of the gram negative bacterial strains.Conclusions:The present study strongly confirms the effectiveness of crude leaves extracts against tested human pathogenic bacterial strains causing several tropical diseases.Since Egyptian clover is used as a fodder plant,it could be helpful in controlling various infectious diseases associated with cattle as well.

Quantum dot biosensor combined with antibody and aptamer for tracing food-borne pathogens

Due to the increasing number of food-borne diseases,more attention is being paid to food safety.Food-borne pathogens are the main cause of food-borne diseases,which seriously endanger human health,so it is necessary to detect and control them.Traditional detection methods cannot meet the requirements of rapid detection of food due to many shortcomings,such as being time-consuming,laborious or requiring expensive instrumentation.Quantum dots have become a promising nanotechnology in pathogens tracking and detection because of their excellent optical properties.New biosensor detection methods based on quantum dots are have been gradually developed due to their high sensitivity and high specificity.In this review,we summarize the different characteristics of quantum dots synthesized by carbon,heavy metals and composite materials firstly.Then,attention is paid to the principles,advantages and limitations of the quantum dots biosensor with antibodies and aptamers as recognition elements for recognition and capture of food-borne pathogens.Finally,the great potential of quantum dots in pathogen detection is summarized.

Evaluation of the antimicrobial activities and mechanisms of synthetic antimicrobial peptide against food-borne pathogens

Food-borne pathogens are an important challenge for the food industry.In this study,the possibility of using the previously designed and synthesized antimicrobial peptide HX-12C as a new food antimicrobial was evaluated.Bacteriostatic and bactericidal tests showed that HX-12C has strong,rapid and broad-spectrum antimicrobial activity against Gram-positive and Gram-negative bacteria.Outer-and inner-membrane permeabilization assays revealed that HX-12C killed food-borne pathogens by inducing membrane permeability.Further Scanning Electron Microscope(SEM)and Transmission Electron Microscope(TEM)also showed that HX-12C can distinctively act on the bacterial membrane leading to the leakage of cellular contents.Moreover,HX-12C also showed anti-biofilm ability in bacterial killing tests.In the food storage test,HX-12C exhibited significant antimicrobial function in raw pork and orange juice.Therefore,HX-12C has shown great potential as a new antimicrobial agent in food storage.

Comparative prevalence of pathogenic and spoilage microbes in chicken sausages from Egypt and Greece

This study investigated the spread of foodborne pathogens: Listeria monocytogenes, Es-cherichia coli O157:H7, Staphylococcus aureus and Salmonella in chicken sausage samples collected from retail markets in Greece and Egypt during 2006 and from Egypt through 2010. Other microbiological parameters;total viable count (TVC), lactic acid bacteria (LAB), pseudomonads (PS), staphylococci (STAPH), Brochothrix thermosphacta (BT), Enterobacteriaceae (EN), Escherichia coli (EC), yeasts and moulds (Y&M) were also counted. Egyptian chicken sausage samples were found to harbor L. mono- cytogenes, Staph. aureus and E. coli O157:H7;with frequencies equivalent to 24%, 60% and 26% of the total samples during 2006 and 37.87%, 64.44% and 41.11% of the total samples during 2010, respectively, while Greek samples were entirely free of theses pathogens. Enrichment techniques indicated the absence of Salmonella from both Greek and Egyptian samples. The obtained results may mobilize food producers and handlers in developing countries to take the due measures reducing food-borne pathogen risks and spoilage flora alongside the poultry chain.

Antimicrobial effects of carnosic acid,kaempferol and luteolin on biogenic amine production by spoilage and food-borne pathogenic bacteria

Antimicrobial effects of carnosic acid,kaempferol and luteolin on biogenic amine(BA)production by five spoilage(Photobacterium damselae,Proteus mirabilis,Enterobacter cloacea,Pseudomonas luteola and Serratia liquefaciens)and five food-borne pathogenic bacteria(Staphylococcus aureus ATCC29213,Enterococcus faecalis ATCC29212,Escherichia coli ATCC25922,Salmonella Paratyphi A NCTC13 and Yersinia enterocolitica NCTC 11175)were investigated.The formation of ammonia(AMN),trimethylamine(TMA)and BAs by all bacterial strains were observed using ornithine decarboxylase broth.BAs,AMN,and TMA were determined by using high performance liquid chromatography(HPLC)method.The results showed that significant differences were observed(P≤0.05)in formation among spoilage and also food-borne bacteria.The impact of phenolic compounds on AMN,TMA and BAs production was dependent on bacterial strains.When total amount of cadaverine(CAD),putrescine(PUT),histamine(HIS)and tyramine(TYR)was considered,the phenolic compounds presented antimicrobial activity against fish spoliage bacteria and food-borne pathogens following the order;kaempferol>carnosic acid>luteolin.These phenolics have potential to be used as food preservatives.

Recent developments of lactic acid bacteria and their metabolites on foodborne pathogens and spoilage bacteria:Facts and gaps

Lactic acid bacteria(LAB)are common microorganisms found in various ecosystems including in plants,fermented foods,and the human body.Exploring the biodiversity of lactic acid microflora and characterization of LAB is a new approach to form a variety of starter communities to create innovative nutritional food matrices.There has been growing interest in LAB isolated from non-dairy environments as these bacteria exhibit significant metabolic diversity and have unique taste-forming activities.Disease may be prevented,or treated by LAB but the treatment of disease conditions with LAB is highly dependent on the host's microbiome and diet and varies in both effectiveness and side effects from individual to individual.Future perspectives on the study of LAB may be related to the expansion of our knowledge in the fields of genetics and genetic engineering.The application of genetic science may help to improve existing strains and develop new strains with characteristics designed for specific purposes.Therefore,the preservative effects of LAB and their metabolites,as well as their interaction on the growth of food borne pathogens and food spoilage microorganisms were elucidated.In addition,the competitive models for microbial growth between LAB and other microorganisms as well as the role of LAB in the elimination of toxic compounds in food products were discussed.Moreover,the review provided an overview of the risks and benefits of using LAB in the food industry.

Grape Phenolic Extract Potentially Useful in the Control of Antibiotic Resistant Strains of <i>Campylobacter</i>

In this work, a grape phenolic extract obtained by methanol extraction has been demonstrated to be effective in inhibiting the growth of different strains and species of Campylobacter, one of the most important bacterial foodborne pathogens causing gastroenteritis worldwide. Noteworthily, it was particularly effective against several strains presenting multiple antibiotic resistances. In all cases, the minimum inhibitory concentration (MIC) was lower than 300 mg GAE/L, being of 60 mg GAE/L for one of the most resistant strains (C. coli LP2), while the others were between 120 mg GAE/L and 180 mg GAE/L. The analytical study of the main phenolic compounds in the grape extract revealed that it was mainly constituted by catechins (85.7%) and phenolic acids (13.7%). However, experiments developed using pure standards demonstrate that phenolic acids (such as gallic, p-hidroxibenzoic, vanillic, and homovanillic acids) were the most active, provoking a Campylobacter growth decrease between 6.7 and 7.6 log, while epicatechin was the only catechin with activity as pure compound (1 log of growth decrease).

Bacteriocins as antimicrobial and preservative agents in food:Biosynthesis,separation and application

Emerging evidence shows the trend of using safe and natural preservatives like bacteriocins in food processing.The increasing demand by the food industry to extend keeping quality and prevent spoilage of various food products has appealed for new preservatives and new methods of conservation.Further,to discover the novel spectrum of antimicrobial compounds that could effectively battle food-borne pathogens,bacteriocins have been intensively studied in the last few years.Recently,great attention has been paid to the application of lactic acid-bacterial bacteriocins targeting food spoilage-causing or pathogenic microorganisms with no significant side effects.Different mechanisms of action like pore-formation,retarding cell-wall/nucleic acid/protein synthesis have been proposed and described for diverse bacteriocins.Therefore,the syntheses,purification of bacteriocins in addition to their applications as antimicrobial and preservative agents in food processing are reviewed in detail.The review will also discuss the preservative effect of bacteriocins and their combinations having multiple modes of action(hurdle approach)to reduce the microbial load as well as antimicrobial resistance.

Progress in advanced methodology development for food-safetyinspection

Food safety is of great concern worldwide,directly related to human health through diet.Multifarious food contaminants could cause severe public health hazards,such as gastrointestinal,neurological,immunological diseases,and even cancers,thus food safety has always been a hot-button issue.Development of rapid,accurate,and non-destructive methods is required to ensure food safety for human consumption.In this review,we summarize the main factors threatening food safety,such as foodborne pathogens,toxins,residues,and adulteration as well as the corresponding food safety inspection methods,focusing on the up-to-date progress.Due to the merits of increasing sensitivity,specificity and convenience,those methods will take food detection and analysis into a new era.

Antimicrobial impacts of selected Lamiaceae plants on bacteria isolated from vegetables and their application in edible films

Fresh vegetables can be contaminated with spoilage and food-borne pathogenic bacteria during cultivation,harvesting,transport and further processing.The essential oils seem a promising solution for preserving vegetables incorporated in edible films.During the study it was determined the prevalence of allochthonous bacteria on some fresh vegetables with classical cultivation and molecular biology techniques.The evaluation of the antibacterial effect of Thymus vulgaris,Origanum vulgare,Mentha piperita and Melissa officinalis essential oils against identified bacteria from vegetables and on some standard foodborne pathogenic bacteria was realized with agar diffusion method.The prevalence of allochthonous bacteria in the examined vegetables was diverse.In some cases,high contamination level could be detected reaching the level of 104 colony forming units/g.The identified bacteria belong to different genera like Bacillus,Enterobacter,Pseudomonas etc.Of the tested plant essential oils,the most pronounced antibacterial effect was detected in the case of thyme and oregano,with over 30 mm inhibition zone.The isolated bacteria from vegetables showed higher resistance to the used essential oils.The results suggest that edible films containing thyme and oregano essential oils possess efficient antibacterial effect against mesophilic aerobic bacteria and Staphylococcus aureus.These findings seem a promising solution for preserving vegetables with natural antimicrobial containing edible films.

Evidence on antimicrobial activity of essential oils and herbal extracts against Yersinia enterocolitica - A review

Yersinia enterocolitica is a very common food-borne pathogen which causes gastrointestinal infections (yersiniosis) in humans and a wide array of animals (e.g.cattle,deer,pigs,and birds).Due to the increasing interest in innovative plant-based substances as common food preservatives,several essential oils and herbal extracts have been investigated deeply that resulted in the emergence of novel anti-Yersinia additives.We reviewed relevant work done by 53 researchers covering literature from the year 2002 to till date.Some species such as Origanum vulgare ,Rosmarinus officinalis ,Thymus vulgaris ,Ocimum basilicum have been extensively investigated and identified that 1,8-cineole,linalool and γ-terpinene as compounds found in the essential oils of these plants have anti-Yersinia activity active food packaging agents.In the same direction,some promising results have been mentioned about the herbal extracts of Murrya koenigii ,Tanacetum vulgare and Tanacetum balsamita,but further investigations are needed for their sustainable implications.According to hierarchical cluster analysis,we found that Lamiaceae and Lauracea as the most significant families with anti-Yersinia activity.Towards the end,we proposed new research trends in order to enhance a global knowledge about the use of natural products against Y.enterocolitica .