Foodborne Microbial Pathogens Research Articles

Point-of-Care Diagnostic System for Viable Salmonella Species via Improved Propidium Monoazide and Recombinase Polymerase Amplification Based Nucleic Acid Lateral Flow.

Salmonella species are prominent foodborne microbial pathogens transmitted through contaminated food or water and pose a significant threat to human health. Accurate and rapid point-of-care (POC) diagnosis is gaining attention in effectively preventing outbreaks of foodborne disease. However, the presence of dead bacteria can interfere with an accurate diagnosis, necessitating the development of methods for the rapid, simple, and efficient detection of viable bacteria only. Herein, we used an improved propidium monoazide (PMAxx) to develop a nucleic acid lateral flow (NALF) assay based on recombinase polymerase amplification (RPA) to differentiate viable Salmonella Typhimurium. We selected an RPA primer set targeting the invA gene and designed a probe for NALF. RPA-based NALF was optimized for temperature (30-43 °C), time (1-25 min), and endonuclease IV concentration (0.025-0.15 unit/µL). PMAxx successfully eliminated false-positive results from dead S. Typhimurium, enabling the accurate detection of viable S. Typhimurium with a detection limit of 1.11 × 102 CFU/mL in pure culture. The developed method was evaluated with spiked raw chicken breast and milk with analysis completed within 25 min at 39 °C. This study has potential as a tool for the POC diagnostics of viable foodborne pathogens with high specificity, sensitivity, rapidity, and cost-effectiveness.

Impact of wet-lab protocols on quality of whole-genome short-read sequences from foodborne microbial pathogens

For successful elucidation of a food-borne infection chain, the availability of high-quality sequencing data from suspected microbial contaminants is a prerequisite. Commonly, those investigations are a joint effort undertaken by different laboratories and institutes. To analyze the extent of variability introduced by differing wet-lab procedures on the quality of the sequence data we conducted an interlaboratory study, involving four bacterial pathogens, which account for the majority of food-related bacterial infections: Campylobacter spp., Shiga toxin-producing Escherichia coli, Listeria monocytogenes, and Salmonella enterica. The participants, ranging from German federal research institutes, federal state laboratories to universities and companies, were asked to follow their routine in-house protocols for short-read sequencing of 10 cultures and one isolated bacterial DNA per species. Sequence and assembly quality were then analyzed centrally. Variations within isolate samples were detected with SNP and cgMLST calling. Overall, we found that the quality of Illumina raw sequence data was high with little overall variability, with one exception, attributed to a specific library preparation kit. The variability of Ion Torrent data was higher, independent of the investigated species. For cgMLST and SNP analysis results, we found that technological sequencing artefacts could be reduced by the use of filters, and that SNP analysis was more suited than cgMLST to compare data of different contributors. Regarding the four species, a minority of Campylobacter isolate data showed the in comparison highest divergence with regard to sequence type and cgMLST analysis. We additionally compared the assembler SPAdes and SKESA for their performance on the Illumina data sets of the different species and library preparation methods and found overall similar assembly quality metrics and cgMLST statistics.

Prevalence Ratio Estimation of Intestinal Parasites and Associated Factors Among Meat Sellers in Ilorin Kwara State Nigeria

Background: Foodborne diseases are a significant public health issue globally, with approximately 30% of the population in developed countries suffering from diarrheal diseases caused mainly by foodborne microbial pathogens. In developing countries, food handlers, including meat sellers, are the primary determinants of food contamination due to poor regulatory systems for food hygiene. This cross-sectional study determined intestinal parasites’ prevalence and associated factors among meat sellers in Nigeria. Methods: Using convenience sampling, 139 meat sellers in four markets in Ilorin, Kwara State, were selected. Stool samples were collected from each participant using a clean and dry stool container. The stool samples were analyzed using direct smear saline and formal-ether concentration techniques. The parasites were identified and counted under a microscope. The primary outcome was the presence of one or more intestinal parasitic species in stool samples. Data were analyzed using descriptive statistics, the Chi-Square test, and binary logistics regression. Results: Of the 139 meat sellers in this study, 74(53.2%) were females, while 65(46.8%) were males. Most participants (43.9%) were in the age group 31-40 years compared to the age group 51-56 years (9.4%), with the least participants. The participants’ education levels varied, with those with primary education (46.8%) being the highest, followed by those with tertiary education (31.7%). Based on religion, 37 (26.6%) participants were Christians, while 102 (73.4%) were Muslims. 59.7% of the meat sellers haboured one or more intestinal parasites. The odds ratio for gender indicates that when holding all other variables constant, a female is 1.7 times more likely to have a parasite than a male. The odds ratios of those with primary and secondary education levels are 1.4 and 1.7, respectively, suggesting that despite the level of education, they were more likely to habour intestinal parasites. The age group did not significantly affect the presence of intestinal parasites (p>0.05). Conclusion: This study shows a high prevalence of intestinal parasites among meat sellers in Ilorin. The findings highlight the importance of implementing preventive measures and promoting awareness to reduce the burden of intestinal parasites in this community. In addition, large-scale screening and mass drug administration are recommended...

A Review of the Construction of the Nanomaterial & Nanocomposite Based Biosensor for Different Applications

Abstract: The heightened attention to food and health safety has prompted researchers to conduct extensive research on biosensors that quickly detect foodborne microbial toxins and pathogens. Biosensors are a blessing due to their simple, cost-effective technique, but there are still some drawbacks with detection time, detection limit, and resilience. Incorporating functionalized nanomaterials into developing biosensors as catalytic tools, immobilization platforms, or optical or electroactive labels has added a new dimension to addressing these challenges. This review paper aims to discuss the construction of different types of nanomaterial-based biosensors in food safety, exosome detection and finally, cancer detection, as well as highlights the advantages of these biosensors over traditional techniques. In addition, a comparative study between the nanomaterial-based biosensors taking into account the linear range and limits of detectionin these mentioned applications was also conducted. Hence, this paper provides key insights into designing and fabricating biosensors utilizing nanomaterials and opens new avenues in disease and food safety research.

Mycostimulator of chitinolytic activity: Thermodynamic studies and its activity against human and food-borne microbial pathogens

Chitinolytic activity and antibiosis are gaining prominence in various biotechnological fields. Dead fungal biomass (DFB) was used as a mycostimulator of chitinase production and antibiosis by Aspergillus fumigatus. The presence of DFB stimulated the synthesis of various secondary metabolites by A. fumigatus that were detected by gas chromatography-mass spectrometry analysis such as 6,8-Di-C-á-glucosylluteolin; bistrimethylsilyl N-acetyl eicosasphinga-4,11-dienine; curan-17-oic acid, 19,20-dihydroxy-, methyl ester, (19S)-; spiro[5à-androstane-3,2′-thiazolidine; retinal; Androsta-1,4-dien-3-one; Panaxydol; Costunolide; Cyclo-(glycyl-L-tyrosyl); and 2-amino ethane thiolsulfuric acid. Chitinase activity was 42.9 Units/mL with the presence DFB, where it was 10.3 Units/mL without DFB. The maximum activity of chitinase was observed at 1.5 g of dead fungal biomass, at 4 h, 50 °C and pH 6. Thermodynamic properties showed ∆H° and ∆S° values of 126 KJ mol-1 and 432 J mol-1 K-1, respectively, indicating an endothermic reaction up to 60 °C. Deviation in ∆G° values confirmed that the reaction at 10 to 20 °C is a nonspontaneous reaction, and at 30 to 60 °C the reaction has a spontaneous nature. DFB encouraged the antimicrobial activity against Pseudomonas aeruginosa, Escherichia coli, Bacillus subtilis, Aspergillus fumigatus, Mucor circinelloides, and Candida albicans with 2.3, 2.2, 2.8, 0.8, 0.7, and 2.2 mm inhibition zones, respectively.

A Campylobacter integrative conjugative element with a CRISPR-Cas9 system targeting competing plasmids: a history of plasmid warfare?

Microbial genomes are highly adaptable, with mobile genetic elements such as integrative conjugative elements (ICE) mediating the dissemination of new genetic information throughout bacterial populations. This is countered by defence mechanism such as CRISPR-Cas systems, which limit invading mobile elements by targetting specific sequences on these elements. Here we have studied the distribution the pVir, pTet and PCC42 plasmids and a new 70-129 kb ICE (CampyICE1) in the foodborne microbial pathogens Campylobacter jejuni and Campylobacter coli. CampyICE1 contains a degenerated Type II-C CRISPR system consisting of a sole Cas9 protein, which is distinct from the previously described Cas9 proteins from C. jejuni andC. coli. CampyICE1 is highly conserved in structure and gene order, containing blocks of genes predicted to be involved in recombination, regulation and conjugation. CampyICE1 was detected in 134/5,829 (2.3%) C. jejunigenomes and 92/1,347 (6.8%) C. coligenomes. Similar ICE were detected in a number ofnon-jejuni/coli Campylobacter species, which lacked a CRISPR-Cas system. Finally, CampyICE1 contained 3 separate short CRISPR spacer arrays, and a total of 124 unique spacers were identified, of which 67 are predicted to target the Campylobacterplasmids pVir, pTet, and pCC42, and 12 predicted to target other Campylobacter plasmids (63.7%). The presence of a functional CampyICE1 Cas9 protein and matching anti-plasmid spacers was associated with the absence of these plasmids (186/214 genomes), implicating that the CampyICE1-encoded CRISPR-Cas has contributed the exclusion of competing plasmids. Hence the CampyICE1 CRISPR-Cas system may be a part of ongoing plasmid warfare in Campylobacter spp.

Metagenomics Approaches for Improving Food Safety: A Review

Advancements in next-generation sequencing technology have dramatically reduced the cost and increased the ease of microbial whole genome sequencing. This approach is revolutionizing the identification and analysis of foodborne microbial pathogens, facilitating expedited detection and mitigation of foodborne outbreaks, improving public health outcomes, and limiting costly recalls. However, next-generation sequencing is still anchored in the traditional laboratory practice of the selection and culture of a single isolate. Metagenomic-based approaches, including metabarcoding and shotgun and long-read metagenomics, are part of the next disruptive revolution in food safety diagnostics and offer the potential to directly identify entire microbial communities in a single food, ingredient, or environmental sample. In this review, metagenomic-based approaches are introduced and placed within the context of conventional detection and diagnostic techniques, and essential considerations for undertaking metagenomic assays and data analysis are described. Recent applications of the use of metagenomics for food safety are discussed alongside current limitations and knowledge gaps and new opportunities arising from the use of this technology.

Determination of Microbial Pathogens and its Abundance in Fresh Kunun-Zaki Drinks: Huge Threat to Public Health

This study investigated the presence and abundance of microbial pathogens in fresh locally produced, packaged and distributed kunun-zaki drinks. A total of 20 samples were randomly purchased from 20 vendors and hawkers. Each of the samples obtained was tenfold serially diluted using sterile peptone water. From the appropriate dilutions, 0.1ml were removed and spread plated on Salmonella-Shigella agar, Mannitol salt agar, and Eosin methylene blue agar plates. The inoculated plates were then incubated at 37°C for 24 hours. This study found that of the 20 kunun-zaki samples investigated, 70% were contaminated by Staphylococcus aureus which ranged from 1.0x104 to 1.21x105 (CFU/ml). Salmonella spp ranged from 1.2x104 to 4.1x104 (CFU/ml), and contaminated 60% of the samples. Escherichia coli ranged from 0.2x104 to 1.1x104 (CFU/ml) and was found in 45% of the samples. The result showed that the locally produced, packaged and distributed kunun-zaki drinks were highly contaminated by foodborne microbial pathogens and it makes it unsafe for human consumption. It further showed that public health is put at risk when unsafe locally produced kunun-zaki beverage is consumed; hence, local producers and Agencies saddled with the responsibility to monitor, supervise and certify food safety must strictly ensure the protection of consumers and public health by insisting that traditional methods of production, packaging and distribution of kunun-zaki drinks follow, maintain and sustain standards that guarantee quality, safety and accessibility. Consumers must resist the urge to purchase kunun-zaki drinks from unverified sources; producers, vendors and hawkers.

Combined aqueous ozone and ultrasound application inhibits microbial spoilage, reduces pesticide residues and maintains storage quality of strawberry fruits

Inappropriate use of pesticides and unhygienic supply chains contaminate fresh fruit and vegetables with health-hazardous micro-organisms and chemical residues. Here, combined efficacy of aqueous ozone and ultrasound to disinfect and decontaminate strawberry fruits from food-borne microbial pathogen and pesticide residues was evaluated. Strawberry fruits were exposed to either ozone (flow rate ≥ 3.3 mg min−1 for 125 g strawberry L−1 water) or ultrasound (40 kHz at 100 W) for 3, 6 and 9 min. Treatment of strawberry fruits with either ozone or ultrasound for 3 min effectively reduced bacterial survival by 44-fold and 17-fold, respectively, compared to control. Then, strawberry fruits were simultaneously treated with both ozone and ultrasound for 1, 2 or 3 min and stored at 2 ± 0.5 °C and 95% relative humidity for 12 days. Ozone and ultrasound treatment for 3 min was most effective in reducing bacterial survival (98%) and residues of various pesticides (98–99%) compared to control. Strawberry fruits treated with ozone and ultrasound for 3 min exhibited delay in fungal decay by 4 days and 4% reduction in weight loss during cold storage for 12 days. Also, gradual decline in total soluble solids, titratable acidity, pH, ascorbic acid and anthocyanins in cold-stored strawberry fruits was also hindered. Ozone and ultrasound treatment for 3 min also restrained 62% higher catalase, 52% higher peroxidase, and 70% higher superoxide dismutase in strawberry tissues compared to control after 12 days in cold storage. Thus, combined treatment of ozone and ultrasound for 3 min increased marketable life of strawberry fruits for 6 more days under cold storage conditions. Overall, results revealed a positive effect of ozone and ultrasound on disinfecting and decontaminating strawberry fruits along with extending their marketable life under cold storage conditions.

Effectiveness of ZnO Nano Particles against the Foodborne Microbial Pathogens E. coli and S. aureus

In this work, various concentrations of ZnO nano particles, prepared by the coprecipitation method with a size range of 47-68 nm, have been investigated as antimicrobial agents. Dilution antimicrobial susceptibility tests were carried out on two kinds of microbes (Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli) according to the standard method recommended by Clinical and Laboratory Standards Institute, CLSI-2015-M07-A10. The results showed that the antimicrobial effect is larger, the higher the concentration of ZnO nano particles in solution. It was also found that Gram-positive microbes are more sensitive to ZnO nano particles when compared with the Gram-negative ones. The minimum inhibitory concentration (MIC) for E. coli was found to be 50 mg/mL while that for S. aureus was 25 mg/mL. The minimum bactericidal concentration (MBC) was 1600 mg/mL for E. coli and 800 mg/mL for S. aureus.

A New Whole Genome Culture-Independent Diagnostic Test (WG-CIDT) for Rapid Detection of Salmonella in Lettuce.

The rapid detection of foodborne microbial pathogens contaminating fresh fruits and vegetables during the intervening period between harvest and consumption could revolutionize microbial quality assurance of food usually consumed raw and those with a limited shelf life. We have developed a sensitive, shotgun whole genome sequencing protocol capable of detecting as few as 1 colony forming unit (cfu) of Salmonella enterica serovar Typhimurium spiked on 25 g of lettuce. The Ion Torrent sequencing platform was used to generate reads of globally amplified DNA from microbes recovered from the surface of lettuce followed by bioinformatic analyses of the nucleotide sequences to detect the presence of Salmonella. The test is rapid and sensitive, and appropriate for testing perishable foods, and those consumed raw, for Salmonella contamination. The test has the potential to be universally applicable to any microbial contaminant on lettuce as long as a suitable bioinformatics pipeline is available and validated. A universal test is expected to pave the way for preventive and precision food safety and the re-shaping of the entire spectrum of food safety investigations from the current disease-limiting, reactive procedure to a proactive, disease prevention process.

Fluorescence in situ hybridization (FISH) in food pathogen detection

Diseases due to food borne microbial pathogens are major public health concern in the world Different methods are used to detect food borne pathogens from different types of foods to prevent from these diseases Out of those methods molecular detection methods have received more concern in the recent past Fluorescence in situ Hybridization is one of such methods used in the detection of food borne microbial pathogens The present situation of using Fluorescence in situ Hybridization to detect food borne microbial pathogens is review in this article

Phenotypic and genotypic characterization of listeria species isolated from poultry and milk products

Listeria monocytogenes has become increasingly important as a food-associated pathogen. It cancause a rare but serious disease called listeriosis with high fatality rates (20–30%) compared withother foodborne microbial pathogens. To estimate the incidence and levels of Listeria spp. indifferent food sources, A total of 200 random samples which collected from different sources 65samples isolated from poultry , 45 from poultry byproducts (Frozen chicken meat balls (kofta),Frozen chicken burger and frozen chicken sausages), 20 from pasteurized milk ,30 from milkproducts (Feta cheese ,cream cheese )and 40 from poultry eggs .Only 7 of total 200 samples (14%)that collected from suspected isolates and detected on Oxford agar, PALCAM agar and ALOA agarwere suspected to be Listeria spp. In poultry, poultry byproducts, pasteurized milk, milk byproductsand poultry eggs, listeria percentage were 0/65(0%), 4/45(1.8), 0/20(0%), 0/30(0%), 3/40(1.2%)isolates, respectively. The in-vitro antimicrobial sensitivity test showed that the isolated L.monocytogenes were sensitive to Sulphamethoxazole /trimethoprim, Gentamycin, Ceftazidime andCephazoline followed by Sulphamethoxazole, ceftriaxone , weak sensitivity to Penicillin . Whilethey were resistant to Erythromycin, Clindamycin, Ampicillin. The results of virulence tests forisolated listeria strains appeared that all of L .monocytogenes were virulent strains as all of themwere positive to CAMP test; showed narrow zone of β–hemolysis on sheep blood agar .The PCRresults for Listeria isolates showed that all strains are L. monoctogenes and have Inl A and hly Agenes positive as virulence genes while negative Inl B, iap and prf A genes.

Plant-mediated effects on an insect-pathogen interaction vary with intraspecific genetic variation in plant defences.

Baculoviruses are food-borne microbial pathogens that are ingested by insects on contaminated foliage. Oxidation of plant-derived phenolics, activated by insect feeding, can directly interfere with infections in the gut. Since phenolic oxidation is an important component of plant resistance against insects, baculoviruses are suggested to be incompatible with plant defences. However, plants among and within species invest differently in a myriad of chemical and physical defences. Therefore, we hypothesized that among eight soybean genotypes, some genotypes would be able to maintain both high resistance against an insect pest and high efficacy of a baculovirus. Soybean constitutive (non-induced) and jasmonic acid (JA)-induced (anti-herbivore response) resistance was measured against the fall armyworm Spodoptera frugiperda (weight gain, leaf consumption and utilization). Indicators of phenolic oxidation were measured as foliar phenolic content and peroxidase activity. Levels of armyworm mortality inflicted by baculovirus (SfMNPV) did not vary among soybean genotypes when the virus was ingested with non-induced foliage. Ingestion of the virus on JA-induced foliage reduced armyworm mortality, relative to non-induced foliage, on some soybean genotypes. Baculovirus efficacy was lower when ingested with foliage that contained higher phenolic content and defensive properties that reduced armyworm weight gain and leaf utilization. However, soybean genotypes that defended the plant by reducing consumption rate and strongly deterred feeding upon JA-induction did not reduce baculovirus efficacy, indicating that these defences may be more compatible with baculoviruses to maximize plant protection. Differential compatibility of defence traits with the third trophic level highlights an important cost/trade-off associated with plant defence strategies.

Proximate Analysis and Microbial Quality of Ready-To-Eat (RTE) Fried Chicken Parts

Fried chicken samples were sourced from two vending sites (from street vendors and fast food centers) in Ikpoba Okha, Oredo and Egor LG as in Benin City. Bacteria growth was observed using Nutrient Agar, the presence of E.coli was detected using Eosine Methylene Blue and Fungi growth was observed by using Potato Dextrose Agar. Proximate composition for the fried chicken samples indicated that the mean value for Moisture content ranged from 55.67 - 59.15%, Crude protein 26.62 - 30.52%, Crude fat 7.87 - 8.72%, Ash 3.06 - 3.88% and Nitrogen free extract 0.10 - 2.50%. The results obtained indicated that the mean values of bacteria count ranged from 4.67 × 106 to 1.2 × 107 cfu/g. The sample from the eatery in Oredo had the highest bacterial count of 1.2 × 107 cfu/g. Thirteen genera of bacteria and seven genera of fungi were isolated. Total fungal counts ranged from 4.70 × 105 to 2.615 × 106 cfu/g. The fried chicken from the street in Ikpoba Okha recorded the highest count with2.615× 106 cfu/g. The fried chicken samples from the eateries had no E.coli and other serious food-borne pathogens; such as Klebsiella sp, Enterobacter sp. The aerobic colony counts of bacteria and fungi were higher thanInternational Food Standards (<105 cfu/g), notwithstand the absence of food-borne microbial pathogens such as E.coli and other serious food-borne pathogens from the eateries and therefore, the products as observed would appear unsafe for human consumption. The isolation and enumeration of bacteria and fungi isolates were also observed. The significance of isolated bacteria and fungi in the fried chicken samples, possible sources of contamination and some recommendations to improve the quality of fried chicken sold in these vending sites were discussed.

Pectin and Xyloglucan Influence the Attachment of Salmonella enterica and Listeria monocytogenes to Bacterial Cellulose-Derived Plant Cell Wall Models.

Minimally processed fresh produce has been implicated as a major source of foodborne microbial pathogens globally. These pathogens must attach to the produce in order to be transmitted. Cut surfaces of produce that expose cell walls are particularly vulnerable. Little is known about the roles that different structural components (cellulose, pectin, and xyloglucan) of plant cell walls play in the attachment of foodborne bacterial pathogens. Using bacterial cellulose-derived plant cell wall models, we showed that the presence of pectin alone or xyloglucan alone affected the attachment of three Salmonella enterica strains (Salmonella enterica subsp. enterica serovar Enteritidis ATCC 13076, Salmonella enterica subsp. enterica serovar Typhimurium ATCC 14028, and Salmonella enterica subsp. indica M4) and Listeria monocytogenes ATCC 7644. In addition, we showed that this effect was modulated in the presence of both polysaccharides. Assays using pairwise combinations of S. Typhimurium ATCC 14028 and L. monocytogenes ATCC 7644 showed that bacterial attachment to all plant cell wall models was dependent on the characteristics of the individual bacterial strains and was not directly proportional to the initial concentration of the bacterial inoculum. This work showed that bacterial attachment was not determined directly by the plant cell wall model or bacterial physicochemical properties. We suggest that attachment of the Salmonella strains may be influenced by the effects of these polysaccharides on physical and structural properties of the plant cell wall model. Our findings improve the understanding of how Salmonella enterica and Listeria monocytogenes attach to plant cell walls, which may facilitate the development of better ways to prevent the attachment of these pathogens to such surfaces.

UV-Heat Treatments for the Control of Foodborne Microbial Pathogens in Chicken Broth.

This investigation established the process criteria for using UV-C light and mild heat (UV-H treatment) to inactivate 5-Log10 cycles (performance criterion) of common foodborne pathogen populations, Escherichia coli, Salmonella Typhimurium, Listeria monocytogenes, and Staphylococcus aureus, when inoculated in chicken broth. To define the target microorganism and the proper UV-H treatment conditions (including UV dose, treatment time, and temperature) that would achieve the stated performance criterion, mathematical equations based on Geeraerd's model were developed for each microorganism. For the sake of comparison, inactivation equations for heat treatments were also performed on the same chicken broth and for the same microorganisms. L. monocytogenes was the most UV-H resistant microorganism at all temperatures, requiring a UV dose between 6.10 J/mL (5.6 min) and 2.26 J/mL (2.09 min) to achieve 5-Log10 reductions. In comparison with UV treatments at room temperatures, the combination of UV and mild heat allowed both the UV dose and treatment time to be reduced by 30% and 63% at 55°C and 60°C, respectively. Compared to heat treatments, the UV-H process reduced the heating time for 5-Log10 reductions of all the investigated microorganisms in chicken broth from 20-fold to 2-fold when the operating temperature varied from 53 to 60°C.

Endophytic Fungal Cellulase for Extraction of Carrageenan and its Use in Antibiotics Amended Film Preparation

The use of non biodegradable plastic based packaging materials has been stopped in several food industries due to their disadvantages, so bio based polymers like polysaccharides are the alternative source for the preparation of films in food packaging. Thus, the present work was aimed to prepare the carrageenan (polysaccharides) based antibiotics amended films to prevent the food borne microbial pathogen in packed foods to extend its shelf life. In this study, morphologically 25 different endophytic fungal strains were isolated from different salt marsh plants, such as, Sweda monica and S.maritima were collected from Kelambakam Coastal area, East Coast of Tamil Nadu, India and they were named as, AEF51 to AEF75. All the fungal isolates were screened for cellulase activity and the maximum cellulase producing potential strain AEF58 was mass cultured. After the partial purification of cellulase it was lyophilized and stored for further use. The red seaweed Amphiroa anceps was collected from Kootapuli Village, Valliyoor Taluk, Tirunelveli District, Tamil Nadu, India. From that, the carrageenan was extracted by biological method using endophytic fungal cellulase. After the extraction of carrageenan the antibiotics such as Amoxycillin, Tetracycline, Chloroamphenical, Erythromycin, Doxycyoline, Ofloxacin, Cephalexin, Dictoxacilin and Ampicillin were amended and different films were prepared using standard protocols. All the films were tested against different seafood borne pathogens such as, E.coli, Vibrio cholerae, V.parahaemolyticus, Salmonella sp, Shigella sp and Listeria sp (Obtained from AMET Microbial Culture Collection Centre). Among them, the Cephalexin amended film was showed the maximum zone of inhibition (ZOI) against all the tested pathogens. From the results, the study concluded that, the extraction of carragenan by biological substances increase the production and antibiotic amended carrageenan based films will be used for food packaging to control the pathogenic microbes and preserve the foods from spoilage.

Modeling the effects of Bunium persicum (Black Zira) essential oil, pH, inoculums size and temperature on the growth of Listeria monocytogenes

Summary Listeriosis is acknowledged as a major foodborne disease throughout the world caused by Listeria monocytogenes. Different factors can affect the growth of food borne microbial pathogens. The aim of this study was to investigate the combined effects of different concentrations of Bunium persicum essential oil (EO) (0%, 0.08%, 0.16%, 0.24%), three incubation temperatures (35oC, 25oC, 4oC), three levels of pH (5, 6, 7) and two inoculum sizes (10 3 and 10 5 cfu ml -1 ) on the growth of Listeria monocytogenes in brain heart infusion (BHI) broth. To evaluate effects of explanatory variable on time to detection (TTD) of bacterial growth, parametric survival models based on the log normal distribution were used. All explanatory variables had significant association with TTD (P<0.05). The final model accurately predicted the growth initiation and inhibition of L. monocytogenes.

Evolution of bactericidal activity of selected food additives against food borne microbial pathogens

Evolution of bactericidal activity of selected food additives against food borne microbial pathogens