Foodborne Pathogens (foodborne + pathogen)

Distribution by Scientific Domains


Selected Abstracts


INHIBITION OF FOODBORNE PATHOGENS AND SPOILING BACTERIA BY ESSENTIAL OIL AND EXTRACTS OF ERIGERON RAMOSUS (WALT.) B.S.P.

JOURNAL OF FOOD SAFETY, Issue 2 2009
ATIQUR RAHMAN
ABSTRACT The antibacterial potential of essential oil and methanolic extracts of Erigeron ramosus (Walt.) B.S.P. was evaluated. Thirty-one components representing 95.3% of the total oil were identified, of which ,-caryophyllene (24.0%), ,-humulene (14.5%), 1,8-cineole (9.0%), eugenol (7.2%), globulol (7.1%), caryophyllene oxide (5.2%), ,-cadinene (5.0%), ,-copaene (4.9%) and widdrol (2.0%) were the major components. The antibacterial activity of essential oil and methanolic extracts of E. ramosus was determined in vitro using the agar diffusion method and minimum inhibitory concentration determination test against 14 (seven gram-positive and seven gram-negative) foodborne bacteria. The essential oil (5 µL/mL, corresponding to 1,000 ppm/disc), methanol extract and its different organic subfractions (7.5 µL/mL, corresponding to 1500 ppm/disc) of E. ramosus displayed a great potential of antibacterial activity against all gram-positive bacteria: Staphylococcus aureus (ATCC 6538 and KCTC 1916), Listeria monocytogenes (ATCC 19116, ATCC 19118, ATCC 19166 and ATCC 15313) and Bacillus subtilis ATCC 6633 and four gram-negative bacteria: Pseudomonas aeruginosa KCTC 2004, Enterobacter aerogenes KCTC 2190 and Escherichia coli (0157:H7 ATCC 43888 and ATCC 8739). The zones of inhibition of different concentrations of essential oil and methanolic extracts against the tested bacteria were found in the range of 10.1,22.3 mm, and MIC values were recorded between 62.5 and 500 µg/mL. PRACTICAL APPLICATIONS The use of essential oil and organic extracts of Erigeron ramosus (Walt.) B.S.P. as antibacterial agents will be suitable for applications on the food industry as natural preservatives or flavoring to control foodborne pathogens. They can be used as growth inhibitors of Listeria monocytogenes, Staphylococcus aureus, Bacillus subtilis, Escherichia coli, Enterobacter aerogenes and Pseudomonas aeruginosa, some important foodborne pathogens and spoiling bacteria. The main reason for their suitability is their natural origin, which consumers find comforting and which is beneficial for the environment, and the very low risk that pathogens will develop resistance to the mixture of components that make up the oil and extracts with their apparent diversity of antibacterial mechanisms. These beneficial characteristics could increase food safety and shelf life. [source]


SIMULTANEOUS RECOVERY AND DETECTION OF FOUR HEAT-INJURED FOODBORNE PATHOGENS IN GROUND BEEF AND MILK BY A FOUR-COMPARTMENT THIN AGAR LAYER PLATE

JOURNAL OF FOOD SAFETY, Issue 2 2006
VIVIAN C.H. WU
ABSTRACT A four-compartment thin agar layer (4-TAL) system was developed to improve operation efficiency and recover injured foodborne pathogens simultaneously. The system consisted of a layer of nonselective agar overlaid on four different selective agars (xylose lysine desoxycholate [XLD], cefsulodin irgasan novobiocin [CIN], modified Oxford medium [MOX] and MacConkey sorbitol agar [MSA]) housed in a four-compartment petri dish. We applied this system to simultaneously recover heat-injured (55C, 10 min) Escherichia coli O157:H7 (MSA), Listeria monocytogenes (MOX), Salmonella Typhimurium (XLD) and Yersinia enterocolitica (CIN) from ground beef and pasteurized milk. No significant difference (P > 0.05) occurred between the single recovery unit (nonselective agar overlaid on one selective agar in a standard petri dish) and the 4-TAL for detecting four heat-injured pathogens in tested samples. Both TAL methods showed greater recovery of four heat-injured pathogens than the pathogen-specific selective media (P < 0.05). The 4-TAL system appears to be efficient for recovery and detection of injured pathogens in food in terms of operation, material and labor costs, and space of incubation. [source]


CALCOFLUOR AS A FLUORESCENT PROBE TO DETECT BIOFILMS OF FOODBORNE PATHOGENS

JOURNAL OF FOOD SAFETY, Issue 1 2003
C.L. ERIKSSON DE REZENDE
ABSTRACT Biofilms enable foodborne pathogens to resist removal from surfaces, survive disinfection and elude detection. This study evaluated the use of Calcofluor, which binds to polysaccharides containing ,-D-glucans, to detect biofilms produced by Salmonella enterica serovar Berta and Salmonella enterica serovar Typhimurium DT104 (St DT104), Escherichia coli, Aeromonas hydrophila, Vibrio cholerae O139 and Hyphomonas adhaerens. Biofilms produced by St DT104, S. berta and V. cholerae on five types of surfaces (glass, polypropylene, TeflonÔ, stainless steel and aluminum) were detected by Calcofluor. Results suggest the potential use of Calcofluor as probes of foodborne pathogens in biofilms. [source]


INFECTIVE DOSE OF FOODBORNE PATHOGENS IN VOLUNTEERS: A REVIEW

JOURNAL OF FOOD SAFETY, Issue 1 2001
MAHENDRA H. KOTHARY
ABSTRACT Risk assessment and impact of foodborne pathogens on the health of different populations was one of the goals identified in the Presidential Food Safety Initiative three-year plan. This entailed estimation of dose-response relationship for foodborne pathogens to humans, either by feeding studies or from outbreaks. For certain pathogens, such as Listeria monocytogenes and Escherichia coli O157:H7, there are no feeding studies due to ethical reasons, and the results from outbreaks are normally used to estimate the infectious dose. The focus of this review is to compile dose-response information in volunteers for several foodborne pathogens including Salmonella, Shigella spp., Campylobacter jejuni, Vibrio spp., Escherichia coli, Cryptosporidium parvum and Entamoeba coli. The infectious dose for different serovars of Salmonella and strains of E. coli was quite large (> 105 organisms), while the infectious dose for some Shigella spp. seemed to be as low as less than 10 organisms. Toxigenic V. cholerae (O1 and O139 serotypes) were infective at a dose of 104 organisms; a non-O1 strain was infective at a much higher dose (106 organisms). C. jejuni, C. parvum and Entamoeba coli appeared to have infectious doses as low as 500 organisms, 10 oocysts, and 1 cyst, respectively. The infectious dose and the dose response are dependent upon the strains used, and the age and physical condition of the individuals, and can therefore show wide variations. In addition, since many of the volunteer studies are carried out by feeding the organisms in a nonfood matrix after neutralizing the stomach acidity, results obtained may not reflect the true dose response. [source]


Book Review: Emerging Foodborne Pathogens.

ENGINEERING IN LIFE SCIENCES (ELECTRONIC), Issue 4 2007
By Y. Motarjemi, M. Adams (Eds.).
No abstract is available for this article. [source]


Wine is Bactericidal to Foodborne Pathogens

JOURNAL OF FOOD SCIENCE, Issue 9 2004
T. Møretrø
ABSTRACT: Red and white wines without added sulfite were tested for antibacterial activity against stationary-phase grown cells of Escherichia coli O157:H7, Listeria monocytogenes, Salmonella Typhimurium, and Staphylococcus aureus. The wines had bactericidal activity against all strains, with the red wine being most potent. S. Typhimurium was most sensitive, with 6 log reduction after 10 min exposure to wine, whereas S. aureus appeared least sensitive to the wines. Mutants having the gene encoding the alternative sigma factor disrupted were generally more sensitive to wine than their wild-type counterparts. When different combinations of ethanol, organic acids, and acidity were tested against the pathogens, it was found that a composition of 0.15% malic acid, 0.6% tartaric acid, 15% ethanol, and pH 3.0 had a strong bactericidal effect. The compounds in the mixture seemed to act synergistically against the pathogens. The pathogens grew in 25% to 40% white wine diluted in brain hearth infusion broth, with S. aureus being able to grow at the highest concentration of wine. Preincubation of the bacteria in sublethal concentrations of wine and ethanol and pH 4.5 did not increase their tolerance against wine or against the mixture of organic acids and ethanol. In conclusion, wine had an antibacterial effect against the pathogens tested. The synergistic effect of organic acids, ethanol, and low pH seems to be responsible for a major part of the antibacterial effect of wine. The alternative sigma factors seemed to be involved in protection of the bacteria against wine. [source]


Use of Conventional Media and Thin Agar Layer Method for Recovery of Foodborne Pathogens from Pressure-treated Poultry Products

JOURNAL OF FOOD SCIENCE, Issue 7 2003
J. Yuste
ABSTRACT: The recovery of 5 pathogens from minced chicken (MC) and liquid whole egg (LWE) was determined with tryptone soya agar (TSA), selective medium, and thin agar layer (TAL; selective medium overlaid with TSA) to evaluate high-pressure effects at 200, 300, 400, and 500 MPa for 1 and 5 min at 20 °C. At 400 MPa for 5 min, Escherichia coli inactivation was 4 log in MC and 5.5 log in LWE, whereas no Salmonella Typhimurium, Yersinia enterocolitica, or Listeria monocytogenes were detected in either product. Staphylococcus aureus was the most pressure-resistant. In general, counts on the 3 media were not different. The TAL method allows differentiation of the inoculated pathogens from background microbiota. [source]


Learning About Foodborne Pathogens: Evaluation of Student Perceptions of Group Project Work in a Food Microbiology Course

JOURNAL OF FOOD SCIENCE EDUCATION, Issue 4 2009
Mark S. Turner
ABSTRACT:, This study examined the experiences of students in an active learning group work exercise in an introductory food microbiology course involving the study of foodborne pathogens. Small groups were required to access, analyze, and present information regarding a single food poisoning bacterium. The presentations contained features and epidemiological information of the pathogen and also a review of a research journal article and a real food poisoning outbreak report involving the pathogen. Analysis of responses from a questionnaire that allowed direct comparisons to be made with other published group work studies revealed that this exercise was a positive learning experience. In particular, students noted improvements in communication, interaction, information acquisition, and organizational skills. [source]


Subtyping of Bacterial Foodborne Pathogens

NUTRITION REVIEWS, Issue 7 2002
Martin Wiedmann D.V.M. Ph.D.
Phenotype-based and DNA-based subtyping methods allow for differentiation of bacterial isolates beyond the species and subspecies level. Bacterial subtyping methods not only have improved our ability to detect and track foodborne disease outbreaks, but also represent tools to track sources of bacterial contamination throughout the food system. The use of subtyping methods furthermore provides an opportunity to better understand the population genetics, epidemiology, and ecology of different foodborne pathogens. The last 5 years have seen tremendous advancement in the development of sensitive, rapid, automated, and increasingly easy-to-use molecular subtyping methods for a variety of different bacterial foodborne pathogens. This review will highlight key aspects of different subtyping methods for bacterial foodborne pathogens and provide examples of their applications in public health, food safety, epidemiology, and population genetics. Molecular subtyping and characterization methods may also facilitate the development of a novel framework for tracking, preventing, and regulating foodborne bacterial diseases, which is based on evolutionary relationships and genetic characteristics rather than traditional species definitions. [source]


PROTEIN PROFILE CHANGES IN ACID ADAPTED LISTERIA MONOCYTOGENES EXHIBITING CROSS-PROTECTION AGAINST AN ACTIVATED LACTOPEROXIDASE SYSTEM IN TRYPTIC SOY BROTH

JOURNAL OF FOOD SAFETY, Issue 1 2000
SADHANA RAVISHANKAR
ABSTRACT Foodborne pathogens often tolerate and survive environmental stress conditions including extreme acidity to varying degrees. One possible reason for this survival may be the production of protective stress proteins during acid shock (ASR) and/or tolerance (ATR) responses. The ASR and ATR of Listeria monocytogenes strains V7, V37 and CA in tryptic soy broth without dextrose acidified with lactic acid were studied. Possible cross-protection of acid adapted cells against an activated lactoperoxidase system was also determined. The strains were either directly challenged at pH 4.0 and 3.5 to study their ASR or initially adapted at pH 5.5 for the equivalent of 1 generation before challenging at pH 4.0 and 3.5 to study their ATR. Adapted and nonadapted cells were challenged at pH 4.5 with or without an activated lactoperoxidase system. In all cases viability was determined by enumeration over a period of 24 or 48 h after challenge and the production of stress proteins analyzed by 2-dimensional gel electrophoresis. While there were some differences in the survival responses for each strain, the acid adapted cells of each strain survived to a greater degree than nonadapted cells at both pH 4.0 (at least 10 fold at 24 h) and pH 3.5 (at least 1000 fold at 6 h) but not at pH 4.5. The acid adapted cells exposed to the lactoperoxidase system survived better (at least 5-fold) than their nonadapted counterparts for all 3 strains at 24 and 48 h. The 2-dimensional gel analysis for all 3 strains showed that the adapted and nonadapted cells underwent a change in their physiology, (at pH 4.0 compared to the control at pH 7.0; at pH 4.5 with the addition of lactoperoxidase system components) in that there was induction as well as repression of several proteins. [source]


NOVEL NONTHERMAL METHODS TO REDUCE VIBRIO VULNIFICUS IN RAW OYSTERS

JOURNAL OF FOOD SAFETY, Issue 3 2003
ABDOLSAMAD BORAZJANI
ABSTRACT Vibrio vulnificus is a foodborne pathogen associated with consumption of raw oyster. No scientific data is available on postharvest treatments of oyster by ultrasound, ozone, and organic acids. This study was designed to investigate the effects of these treatments on inactivation of V. vulnificus naturally present in the in-shell or half-shelled oysters. In in-shell oysters, these treatments were not effective in reducing the number of this pathogen. Half-shelled oysters treated with ultrasound, and ozone in 2% saline for 30 min had 1 and 1.5 log less V. vulnificus, respectively (p<0.05). Treatment of half-shelled oysters by 50 and 100% lemon juice, 5% citric acid, 10% citric acid, or vinegar for 30 min resulted in a significant reduction (2,4 log) in the numbers of V. vulnificus (p<0.05). Although these methods significantly reduced the population of V. vulnificus in raw oysters, they were not able to reduce the numbers of this pathogen to acceptable level (<3 MPN/g). [source]


A small outbreak of listeriosis potentially linked to the consumption of imitation crab meat

LETTERS IN APPLIED MICROBIOLOGY, Issue 2 2000
J.M. Farber
A small outbreak of listeriosis involving two previously healthy adults occurred in Ontario. Food samples obtained from the refrigerator of the patients included imitation crab meat, canned black olives, macaroni and vegetable salad, spaghetti sauce with meatballs, mayonnaise and water. All of the samples except the water contained Listeria monocytogenes. The three most heavily contaminated samples were the imitation crab meat, the olives and the salad which contained 2·1 × 109, 1·1 × 107 and 1·3 × 106 cfu g,1, respectively. L. monocytogenes serotype 1/2b was isolated from the patients, as well as from the opened and unopened imitation crab meat. Molecular typing of the isolates by both randomly amplified polymorphic DNA (RAPD) and pulsed-field gel electrophoresis (PFGE) typing demonstrated the imitation crab meat and clinical strains to be indistinguishable. Challenge studies performed with a pool of L. monocytogenes strains showed that imitation crab meat, but not olives, supported growth of the organism. In this study we have shown for the first time the potential involvement of imitation crab meat in a small outbreak of listeriosis. In terms of disease prevention, temperature control is critical to prevent or reduce the growth of this foodborne pathogen. In addition, with refrigerated products having a long (> 30 d) shelf life, additional safety factors must be used to prevent the growth of foodborne pathogens such as L. monocytogenes. [source]


Advances in Campylobacter biology and implications for biotechnological applications

MICROBIAL BIOTECHNOLOGY, Issue 3 2010
Byeonghwa Jeon
Summary Campylobacter jejuni is a major foodborne pathogen of animal origin and a leading cause of bacterial gastroenteritis in humans. During the past decade, especially since the publication of the first C. jejuni genome sequence, major advances have been made in understanding the pathobiology and physiology of this organism. It is apparent that C. jejuni utilizes sophisticated mechanisms for effective colonization of the intestinal tracts in various animal species. Although Campylobacter is fragile in the environment and requires fastidious growth conditions, it exhibits great flexibility in the adaptation to various habitats including the gastrointestinal tract. This high adaptability is attributable to its genetically, metabolically and phenotypically diverse population structure and its ability to change in response to various challenges. Unlike other enteric pathogens, such as Escherichia coli and Salmonella, Campylobacter is unable to utilize exogenous glucose and mainly depends on the catabolism of amino acids as a carbon source. Campylobacter proves highly mutable in response to antibiotic treatments and possesses eukaryote-like dual protein glycosylation systems, which modify flagella and other surface proteins with specific sugar structures. In this review we will summarize the distinct biological traits of Campylobacter and discuss the potential biotechnological approaches that can be developed to control this enteric pathogen. [source]


Cover Picture: Electrophoresis 13'2010

ELECTROPHORESIS, Issue 13 2010
Article first published online: 30 JUN 2010
Issue no. 13 is a special issue on "Food and Beverage Analysis" comprising 23 contributions distributed over four distinct parts. Part I "presents six review papers, five of them are focused on the use of capillary electromigration techniques for detecting enantiomers, nucleosides, nucleotides, pesticides and contaminants in foods as well as foodborne pathogens". The sixth review deals with the application of two-dimensional electrophoresis to investigate food allergens. A series of original contributions on the use of CE, CEC and MEKC in the analysis of food constituents are grouped in Part II. Part III presents "Works on the detection of genetically modified foods by CGE and the analysis of antibiotics and antioxidants by microemulsion electrokinetic chromatography". Finally, Part IV is on the use of CE-MS to analyze endocrine disruptors and polyphenols in different food matrices, and on the speciation analysis of arsenic and selenium compounds in different foodstuffs by capillary electrophoresis-inductively coupled plasma-mass spectrometry. [source]


Evaluation of antibacterial activity of Indian spices against common foodborne pathogens

INTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 8 2007
Papachan Karur Sofia
Summary The present study was designed to evaluate the antimicrobial activity of six Indian spice extracts, namely clove, cinnamon, mustard, garlic, ginger and mint. All of these have been traditionally used in folk medicine, and are still used in the alternative system of health care. The antimicrobial activity of these commonly used Indian spices was tested against three potent foodborne pathogens, namely Escherichia coli,Staphylococcus aureus and Bacillus cereus, which are responsible for many health-related problems. These were tested using paper disc diffusion method, cup method and dilution method (qualitative). The results showed that the extracts of clove, cinnamon and mustard had good inhibitory action at 1% concentration, while garlic showed medium activity. At 3% concentration, complete bactericidal effect was achieved. Ginger and mint showed negligible antibacterial activity against these pathogens at the same concentration. [source]


Bacterial dormancy in Campylobacter: abstract theory or cause for concern?

INTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 6 2001
John E. Moore
For the past 100 years, since the birth of modern microbiology, this discipline has predominantly relied on the ability to culture micro-organisms in vitro on artificial synthetic culture media under controlled conditions in the laboratory. However, sometimes it is not possible to detect foodborne pathogens using such conventional techniques. Employment of these techniques can also lead to a delay in detection of pathogens. The ,viable but non-culturable' (VNC) cellular form has been demonstrated in Campylobacter jejuni, representing a resting or dormant stage, which is induced through cell stress including starvation. This form is extremely difficult to detect and generally requires complex and sophisticated technology which is usually not available in most routine food microbiology laboratories. This review aims at examining the role of this cell form in Campylobacter, including their historical evolution, formation, physiology, detection and to discuss the challenges that this form presents to food safety. [source]


Microbiological analysis of composts produced on South Carolina poultry farms

JOURNAL OF APPLIED MICROBIOLOGY, Issue 6 2010
M.W. Shepherd Jr
Abstract Aims:, The purpose of this study was to determine whether the methods used in compost operations of small and medium-sized poultry forms resulted in the production of an amendment free of foodborne pathogens. Methods and Results:, Nine compost heaps on five South Carolina poultry farms were surveyed at different stages of the composting process. Compost samples were analysed for coliforms and enriched for Escherichia coli O157:H7, Salmonella spp. and Listeria monocytogenes. The waste materials and composting practices differed among the surveyed farms. On two farms, new materials were added to heaps that had previously completed the active composting phase. Five compost heaps did not reach an internal temperature of 55°C, and c. 62% of all internal samples in the first composting phase contained moisture contents <40%. Escherichia coli was detected in 63% of the surface samples (n = 38) and 9·8% of the internal samples (n = 82) from the first composting phase, as compared with 16·7% of the surface samples (n = 12) and 0% internal samples (n = 24) from the second composting phase. Salmonella was detected in 26 and 6·1% of all surface and internal samples collected from heaps in the first composting phase, respectively, but was absent in all compost samples undergoing a second composting phase. The predominant Salmonella serotypes were Thompson, Montevideo and Anatum. Neither E. coli O157:H7 nor L. monocytogenes was detected in any of the samples. Conclusions:, Our results indicate that the conditions at the compost surface are suitable for pathogen survival, and the complete composting process can result in the elimination of pathogens in poultry wastes. Significance and Impact of the Study:, This research provides information regarding the effectiveness of the composting practices and microbiological quality of poultry compost produced by small- and medium-sized farms. Ensuring the safety of compost that may be applied to soils should be an integral part of preharvest food safety programme. [source]


Fructose and glucose mediates enterotoxin production and anaerobic metabolism of Bacillus cereus ATCC14579T

JOURNAL OF APPLIED MICROBIOLOGY, Issue 3 2009
O. Ouhib-Jacobs
Abstract Aims:, To determine the effects of carbohydrates on Bacillus cereus ATCC14579T anaerobic metabolism and enterotoxin production in amino acids rich medium. Methods and Results:,Bacillus cereus anaerobic growth on different carbohydrates (glucose, fructose, sucrose or glucose,fructose mixture) was examined in synthetic mMOD medium under continuous cultures (, = 0·2 h,1). Fermentation end-products, flux partitioning at each key branch points of the mixed acid pathway and consumption or production of amino acids were determined. On both fructose and sucrose, ATP production was favoured via acetate production from acetyl-CoA. In addition, amino acids present in the growth medium showed significant variations with high consumption of serine and net production of glutamate and alanine on some or all sugars. Enterotoxins Hbl and Nhe production was high during growth on fructose (or mixtures involving a fructose moiety). Conclusions:, Fructose was identified as a key sugar influencing anaerobic metabolism and toxin production of B. cereus. Significance and Impact of the Study:, The physiological differences associated with the fermentation of the various carbohydrates clearly modify toxinogenesis indicating that the risk of foodborne pathogens is to some extent dependent upon the prevailing nutritional environment. [source]


Interactions of Salmonella enterica with lettuce leaves

JOURNAL OF APPLIED MICROBIOLOGY, Issue 6 2009
Y. Kroupitski
Abstract Aims:, To investigate the interactions of Salmonella enterica with abiotic and plant surfaces and their effect on the tolerance of the pathogen to various stressors. Methods and Results:,Salmonella strains were tested for their ability to form biofilm in various growth media using a polystyrene plate model. Strong biofilm producers were found to attach better to intact Romaine lettuce leaf tissue compared to weak producers. Confocal microscopy and viable count studies revealed preferential attachment of Salmonella to cut-regions of the leaf after 2 h at 25°C, but not for 18 h at 4°C. Storage of intact lettuce pieces contaminated with Salmonella for 9 days at 4°C resulted only in small changes in population size. Exposure of lettuce-associated Salmonella cells to acidic conditions (pH 3·0) revealed increased tolerance of the attached vs planktonic bacteria. Conclusions:, Biofilm formation on polystyrene may provide a suitable model to predict the initial interaction of Salmonella with cut Romaine lettuce leaves. Association of the pathogen with lettuce leaves facilitates its persistence during storage and enhances its acid tolerance. Significance and Impact of the Study:, Understanding the interactions between foodborne pathogens and lettuce might be useful in developing new approaches to prevent fresh produce-associated outbreaks. [source]


Combined effect of mild heat and acetic acid treatment for inactivating Escherichia coli O157:H7, Listeria monocytogenes and Salmonella typhimurium in an asparagus puree

JOURNAL OF APPLIED MICROBIOLOGY, Issue 5 2006
J.-H. Shin
Abstract Aims:, This study was conducted to validate combined heat and acid treatments for inactivating Escherichia coli O157:H7, Listeria monocytogenes and Salmonella typhimurium in an acidified brine containing, or pickled, asparagus model food. Methods and Results:, A mixture of three strains of E. coli O157:H7, L. monocytogenes and S. typhimurium were inoculated onto pickled asparagus samples. Combinations of various concentrations of acetic acid [0%, 0·25%, 0·5%, 0·75%, 1%, 1·5% and 2% (v/v)] and various temperatures (40°C, 50°C, 60°C and 75°C) were investigated. Following treatment, asparagus samples were stored at room temperature and enumerated at 0, 0·5, 1, 2 and 3 days. Heat and acetic acid treatments were synergistic. The inhibitory effects of these combined treatments on the tested foodborne pathogens were also effective during storage. Loss of green colour in the pickled asparagus significantly increased with increasing concentrations of acetic acid. Conclusions:, Using a combination of mild heat and acetic acid treatments can successfully control E. coli O157:H7, L. monocytogenes and S. typhimurium in pickled asparagus, combinations of heat and acid are synergistic and effective treatments can be selected to reduce adverse effect on colour which occur during product storage. Significance and Impact of the Study:, Mild heating plus acetic acid treatment are synergistic, so combined treatments can be developed, which would lower the temperature and amount of acetic acid required for minimally processed vegetables while maintaining pathogen control. [source]


PURIFICATION AND CHARACTERIZATION OF BACTERIOCIN FROM WEISSELLA PARAMESENTEROIDES DFR-8, AN ISOLATE FROM CUCUMBER (CUCUMIS SATIVUS)

JOURNAL OF FOOD BIOCHEMISTRY, Issue 5 2010
AJAY PAL
ABSTRACT Bacteriocin from Weissella paramesenteroides DFR-8 isolated from cucumber (Cucumis sativus) was purified by using only two steps, viz., pH-mediated cell adsorption,desorption method and gel permeation chromatography. A single peak observed in the purity check by analytical Reverse Phase-High Performance Liquid Chromatography (Waters 600 analytical HPLC system, Milford, MA) and a single band (molecular weight,3.74 kDa) shown on SDS-PAGE analysis strongly indicated the homogeneity of the bacteriocin preparation. Treatment with proteolytic enzymes abolished the antimicrobial activity indicating the proteinaceous nature of bacteriocin. The purified bacteriocin exhibited a broad inhibitory spectrum against foodborne pathogens and spoilage microorganisms, including gram-negative bacteria such as Salmonella typhimurium, Vibrio parahaemolyticus, Aeromonas hydrophila and Listeria monocytogenes. Response surface methodology was employed to study the interactive effect of temperature and pH on bacteriocin activity, and a regression equation was developed. The bacteriocin retained full activity after storage at,20C for 90 days, while partial and complete activity loss was observed when stored at 4 and 37C, respectively. PRACTICAL APPLICATION In recent years, bacteriocins of lactic acid bacteria have gained much attention as food biopreservatives because of their origin from generally regarded as safe organisms. In spite of various bacteriocins studied worldwide, studies on bacteriocins of Weissella paramesenteroides remain rare. The present work involves the purification of bacteriocin up to absolute homogeneity from W. paramesenteroides, an isolate first time reported from cucumber (Cucumis sativus). The purified bacteriocin (molecular weight ,3.74 kDa) was found to inhibit a large number of foodborne pathogens, including Listeria monocytogenes, which is resistant to commercially available bacteriocin, i.e., nisin. The application of central composite rotatable design enabled us to design a regression equation from which the residual activity of bacteriocin can be predicted at any given conditions of temperature and pH within the experimental domain. The broad inhibitory spectrum and thermostability of bacteriocin suggest its potential application in food preservation. [source]


ACIDIC ELECTROLYZED WATER PROPERTIES AS AFFECTED BY PROCESSING PARAMETERS AND THEIR RESPONSE SURFACE MODELS

JOURNAL OF FOOD PROCESSING AND PRESERVATION, Issue 1 2004
GABRIEL O. I. EZEIKE
Several studies of acidic electrolyzed (EO) water demonstrated the efficacy of EO water for inactivation of different foodborne pathogens and reported on the chemical species present in EO water. This study was conducted to investigate the effect of production parameters (voltage, NaCl concentration, flow rate, and temperature) on the properties of EO water and to model the complex reactions occurring during the generation of EO water. At 0.1% salt concentration, EO water was produced at 2, 10, and 28 V. However, due to high conductivity of the electrolyte at 0.5% salt concentration, the voltage applied across the cell was limited to 7 V. The electrolyte flow rate was set at 0.5, 2.5, and 4.5 L/mn. For pH and oxidation-reduction potential (ORP), NaCl concentration was the most significant factor followed by voltage, electrolyte flow rate and temperature, respectively. However, in the case of residual chlorine, flow rate was relatively more important than voltage. Response surface methodology yielded models to predict EO water properties as functions of the process parameters studied, with very high coefficients of determination (R2= 0.872 to 0.938). In general, the higher the NaCl concentration and voltage, the higher the ORP and residual chlorine of EO water. Increased electrolyte flow rate will produce EO water with lower ORP and residual chlorine due to the shorter residence time in the electrolytic cell. [source]


VALIDATION OF PATHOGEN DESTRUCTION DURING MANUFACTURE OF A MEAT-BASED POTATO SNACK (CHIPAROO)

JOURNAL OF FOOD PROCESSING AND PRESERVATION, Issue 6 2003
S. J. KIERAS
ABSTRACT A Chiparoo is a comminuted rabbit and sweet potato dehydrated snack chip manufactured using a process suitable for underdeveloped regions of the world. The purpose of this study was to evaluate the ability of the Chiparoo manufacturing process to adequately deliver 5 log reductions in Listeria monocytogenes, Escherichia coli O157:H7, Salmonella typhimurium, and Staphylococcus aureus per gram of food product. These four pathogens were inoculated into regular (pH , 6.0) and lime juice added (pH , 5.0) formulations of rabbit and sweet potato Chiparoos. They were inoculated as a cocktail of four microorganisms at concentrations of approximately 106/g of each pathogen. Individual inoculations of each pathogen at the same concentration (106/g) were also prepared. After inoculation, the product was held for 5 h at 37C, to simulate the maximum hold time in a sub-Saharan Africa manufacturing facility, then dehydrated at 55C (+/- 5C) for 9 h. Samples of the product were taken during the hold and dehydration steps, decimally diluted and plated on the appropriate enumeration medium. The regular formulation (pH , 6.0) did not achieve the required 5 log reduction of each of the four pathogens, while the lime juice added formulation (pH , 5.0) achieved the desired minimum 5 log reduction for each of the four foodborne pathogens tested. [source]


SIMULTANEOUS DETECTION OF LISTERIA MONOCYTOGENES, STAPHYLOCOCCUS AUREUS, SALMONELLA ENTERICA AND ESCHERICHIA COLI O157:H7 IN FOOD SAMPLES USING MULTIPLEX PCR METHOD

JOURNAL OF FOOD SAFETY, Issue 3 2009
D. ZHANG
ABSTRACT In this study, one multiplex polymerase chain reaction (MPCR) assay was developed for simultaneous detection of four foodborne pathogens, i.e., Listeria monocytogenes, Staphylococcus aureus, Salmonella enterica and Escherichia coli O157:H7. Five specific primer pairs were designed based on the nucleotide sequences of hemolysin gene (hly) of Listeria monocytogenes, thermostable nuclease gene (nuc) of Staphylococcus aureus, invasion gene (invA) of Salmonella enterica, shiga-like toxin gene (stx) and intimin gene (eae) of Escherichia coli O157:H7 in this assay. The specificity and sensitivity of the MPCR method were validated, and the limit of detection (LOD) of this method was about 10 copies. One cfu/mL each of these foodborne pathogens spiked in practical food samples, i.e., ground meat, beef, pork, fish, shrimp, cheese, canola leaf and cabbage, could be detected simultaneously after 24 h enrichment at a rate of 87.5%, indicating that the established MPCR detection method was effective and suitable for practical use. PRACTICAL APPLICATIONS This study presents a quick and effective identification method to simultaneous monitor four foodborne pathogens in food samples. The specificity and sensitivity of this method can be used to unambiguously identify these four foodborne pathogens in practical food samples based on the species-specific genes. Therefore, this detection method is applicable for surveillance measures of these four foodborne pathogens in the food production chain. [source]


INHIBITION OF FOODBORNE PATHOGENS AND SPOILING BACTERIA BY ESSENTIAL OIL AND EXTRACTS OF ERIGERON RAMOSUS (WALT.) B.S.P.

JOURNAL OF FOOD SAFETY, Issue 2 2009
ATIQUR RAHMAN
ABSTRACT The antibacterial potential of essential oil and methanolic extracts of Erigeron ramosus (Walt.) B.S.P. was evaluated. Thirty-one components representing 95.3% of the total oil were identified, of which ,-caryophyllene (24.0%), ,-humulene (14.5%), 1,8-cineole (9.0%), eugenol (7.2%), globulol (7.1%), caryophyllene oxide (5.2%), ,-cadinene (5.0%), ,-copaene (4.9%) and widdrol (2.0%) were the major components. The antibacterial activity of essential oil and methanolic extracts of E. ramosus was determined in vitro using the agar diffusion method and minimum inhibitory concentration determination test against 14 (seven gram-positive and seven gram-negative) foodborne bacteria. The essential oil (5 µL/mL, corresponding to 1,000 ppm/disc), methanol extract and its different organic subfractions (7.5 µL/mL, corresponding to 1500 ppm/disc) of E. ramosus displayed a great potential of antibacterial activity against all gram-positive bacteria: Staphylococcus aureus (ATCC 6538 and KCTC 1916), Listeria monocytogenes (ATCC 19116, ATCC 19118, ATCC 19166 and ATCC 15313) and Bacillus subtilis ATCC 6633 and four gram-negative bacteria: Pseudomonas aeruginosa KCTC 2004, Enterobacter aerogenes KCTC 2190 and Escherichia coli (0157:H7 ATCC 43888 and ATCC 8739). The zones of inhibition of different concentrations of essential oil and methanolic extracts against the tested bacteria were found in the range of 10.1,22.3 mm, and MIC values were recorded between 62.5 and 500 µg/mL. PRACTICAL APPLICATIONS The use of essential oil and organic extracts of Erigeron ramosus (Walt.) B.S.P. as antibacterial agents will be suitable for applications on the food industry as natural preservatives or flavoring to control foodborne pathogens. They can be used as growth inhibitors of Listeria monocytogenes, Staphylococcus aureus, Bacillus subtilis, Escherichia coli, Enterobacter aerogenes and Pseudomonas aeruginosa, some important foodborne pathogens and spoiling bacteria. The main reason for their suitability is their natural origin, which consumers find comforting and which is beneficial for the environment, and the very low risk that pathogens will develop resistance to the mixture of components that make up the oil and extracts with their apparent diversity of antibacterial mechanisms. These beneficial characteristics could increase food safety and shelf life. [source]


ASSESSMENT OF MICROBIAL CONTAMINANTS PRESENT ON VACUUM LOADERS IN SHELL EGG PROCESSING FACILITIES

JOURNAL OF FOOD SAFETY, Issue 3 2008
D.R. JONES
ABSTRACT This study was conducted to determine the pathogen prevalence on vacuum loader cup surfaces. An off-line (birds housed off-site) and a mixed (birds housed on-site and eggs brought from outside production) operation shell egg processing facility were sampled three times each. Twenty vacuum loader cups were randomly rinsed with sterile saline per visit. Total aerobic microorganisms and Enterobacteriaceae were enumerated, and the prevalence of Salmonella, Campylobacter and Listeria was determined. Aerobic microorganisms were ,5 log cfu/mL, with higher levels noted in the mixed operation. Enterobacteriaceae levels averaged 2.5 log cfu/mL but were higher in the off-line facility. Campylobacter was detected in 1.6% of the samples. Salmonella was detected in 3.3% of the samples with isolates serotyped as Salmonella anatum and Salmonella heidelberg. There was a high prevalence of Listeria (72%). Confirmed isolates were identified as Listeria innocua (98.8%) and Listeria monocytogenes (1.2%). Identification of the populations present on the cup surfaces will allow for the development of more effective cleaning and disinfection programs. PRACTICAL APPLICATIONS Vacuum loaders have previously been determined to be reservoirs for microorganisms in shell egg processing plants. Assessing the prevalence of prominent foodborne pathogens (Salmonella, Campylobacter and Listeria) on the vacuum loader cup surface would allow for more targeted approaches to cleaning and sanitation. High levels of aerobic organisms and Enterobacteriaceae were detected (,5 and 2.5 log cfu/mL, respectively). Furthermore, Campylobacter and Salmonella were also found, but at low prevalence. Listeria was detected in 72% of the samples. Cleaning and sanitation programs currently utilized in shell egg processing facilities need to be reassessed, and new technologies need to be developed to address the presence of Salmonella, Campylobacter and Listeria. [source]


LISTERIA MONOCYTOGENES AND ESCHERICHIA COLI O157:H7 INHIBITION IN VITRO BY LIPOSOME-ENCAPSULATED NISIN AND ETHYLENE DIAMINETETRAACETIC ACID

JOURNAL OF FOOD SAFETY, Issue 2 2008
T. MATTHEW TAYLOR
ABSTRACT Encapsulation technologies that effectively reduce antimicrobial interaction with food components or protect antimicrobial compounds from food processing measures have the potential to improve the microbiological safety of ready-to-eat foods. Recent application of liposomes for the preservation of cheese has spurred research into their utility in other food matrices. To ascertain the feasibility of encapsulated antimicrobial for the control of Listeria monocytogenes and Escherichia coli O157:H7 growth in a model system, nisin (5.0 and 10.0 µg/mL) and the chelator ethylene diaminetetraacetic acid were entrapped in phospholipid liposomes. While phosphatidylcholine (PC) liposomes did not produce significant inhibition of target pathogens, PC/phosphatidylglycerol 8/2 and 6/4 (mol%) produced significant inhibition of pathogens. Near-complete inhibition of E. coli O157:H7 with liposomal antimicrobials at concentrations below those reported necessary for unencapsulated antimicrobial and chelator suggests that liposomes may represent a powerful technology for the encapsulation of antimicrobials and the control of foodborne pathogens. PRACTICAL APPLICATIONS The activity of many antimicrobials is abolished in many food products for a variety of reasons. Interference and cross-reactions of the antimicrobial and various food constituents, such as protein and fat, are difficult to overcome and often require large amounts of antimicrobial in order to gain significant reductions in the pathogen load in a product. Loss of solubility of some antimicrobials based on pH or ionic strength will negatively affect the antimicrobial potential of a compound like nisin. Liposome encapsulation technologies, such as that reported here, may allow for the maintenance of antimicrobial activity by protecting the antimicrobial against cross-reactions with food components. Additionally, the liposome core represents a microenvironment which can be manipulated by the manufacturer in order to preserve optimal antimicrobial solubility and stability conditions until the time of release. [source]


INCIDENCE OF LISTERIA SPECIES IN SEAFOOD PRODUCTS OF MYSORE, INDIA

JOURNAL OF FOOD SAFETY, Issue 4 2007
AHMED SAIF MOHAREM
ABSTRACT Listeria monocytogenes is one of the most important foodborne pathogens causing illness in humans and animals. Thus, a study was undertaken to investigate the incidence of Listeria species in fresh and dry fish samples marketed in Mysore, India. A total of 164 fresh and dry fish samples collected from retail outlet shops of Mysore, South India, during the period August 2005 through August 2006 were examined for the presence of Listeria species by using ISO 11290 protocol. The incidence of Listeria species was positive in 62 samples (37.8%), and L. monocytogenes was isolated from only three (1.83%) fresh fish samples. Listeria species in seafood were predominant in the order of Listeria innocua (50) (30.49%), Listeria grayi (eight) (4.9%), L. monocytogenes (three) (1.83%) and Listeria seeligeri (one) (0.6%). All isolates of Listeria species were subjected to polymerase chain reaction (PCR) and confirmed with the genus-specific set of primers, and special emphasis was given for detection of L. monocytogenes using a species-specific set of primers. The specificity and sensitivity of PCR were in good correlation with the cultural methods. The results indicated a high incidence of Listeria species and L. monocytogenes in fresh fish samples. This warrants the need for appropriate control measures as this would pose a serious threat to human health. [source]


SIMULTANEOUS RECOVERY AND DETECTION OF FOUR HEAT-INJURED FOODBORNE PATHOGENS IN GROUND BEEF AND MILK BY A FOUR-COMPARTMENT THIN AGAR LAYER PLATE

JOURNAL OF FOOD SAFETY, Issue 2 2006
VIVIAN C.H. WU
ABSTRACT A four-compartment thin agar layer (4-TAL) system was developed to improve operation efficiency and recover injured foodborne pathogens simultaneously. The system consisted of a layer of nonselective agar overlaid on four different selective agars (xylose lysine desoxycholate [XLD], cefsulodin irgasan novobiocin [CIN], modified Oxford medium [MOX] and MacConkey sorbitol agar [MSA]) housed in a four-compartment petri dish. We applied this system to simultaneously recover heat-injured (55C, 10 min) Escherichia coli O157:H7 (MSA), Listeria monocytogenes (MOX), Salmonella Typhimurium (XLD) and Yersinia enterocolitica (CIN) from ground beef and pasteurized milk. No significant difference (P > 0.05) occurred between the single recovery unit (nonselective agar overlaid on one selective agar in a standard petri dish) and the 4-TAL for detecting four heat-injured pathogens in tested samples. Both TAL methods showed greater recovery of four heat-injured pathogens than the pathogen-specific selective media (P < 0.05). The 4-TAL system appears to be efficient for recovery and detection of injured pathogens in food in terms of operation, material and labor costs, and space of incubation. [source]


CALCOFLUOR AS A FLUORESCENT PROBE TO DETECT BIOFILMS OF FOODBORNE PATHOGENS

JOURNAL OF FOOD SAFETY, Issue 1 2003
C.L. ERIKSSON DE REZENDE
ABSTRACT Biofilms enable foodborne pathogens to resist removal from surfaces, survive disinfection and elude detection. This study evaluated the use of Calcofluor, which binds to polysaccharides containing ,-D-glucans, to detect biofilms produced by Salmonella enterica serovar Berta and Salmonella enterica serovar Typhimurium DT104 (St DT104), Escherichia coli, Aeromonas hydrophila, Vibrio cholerae O139 and Hyphomonas adhaerens. Biofilms produced by St DT104, S. berta and V. cholerae on five types of surfaces (glass, polypropylene, TeflonÔ, stainless steel and aluminum) were detected by Calcofluor. Results suggest the potential use of Calcofluor as probes of foodborne pathogens in biofilms. [source]