Category Archives: Pathogen

Research – Food Poisoning and Online Food Shopping

Liebert Open Access

Food sold over the internet is an emerging business that also presents a concern with regard to food safety. A nationwide foodborne disease outbreak associated with sandwiches purchased from an online shop in July 2010 is reported. Consumers were telephone interviewed with a structured questionnaire and specimens were collected for etiological examination. A total of 886 consumers were successfully contacted and completed the questionnaires; 36.6% had become ill, with a median incubation period of 18 h (range, 6–66 h). The major symptoms included diarrhea (89.2%), abdominal pain (69.8%), fever (47.5%), headache (32.7%), and vomiting (17.3%). Microbiological laboratories isolated Salmonella enterica serovar Enteritidis, Salmonella Virchow, Staphylococcus aureus, Bacillus cereus, and enterotoxigenic Escherichia coli from the contaminated sandwiches, Salmonella Enteritidis and Salmonella Virchow from the patients, and Salmonella Enteritidis and Staphylococcus aureus from food handlers. Pulsed-field gel electrophoresis genotyping suggested a common origin of Salmonella bacteria recovered from the patients, food, and a food handler. Among the pathogens detected, the symptoms and incubation period indicated that Salmonella, likely of egg origin, was the probable causative agent of the outbreak. This outbreak illustrates the importance of meticulous hygiene practices during food preparation and temperature control during food shipment and the food safety challenges posed by online food–shopping services.

Research – Pathogen Adaptation – Salmonella – Staphylococcus aureus

Science DailyiStock_000012710183Small

Bacteria can evolve rapidly to adapt to environmental change. When the “environment” is the immune response of an infected host, this evolution can turn harmless bacteria into life-threatening pathogens. A study published on December 12 in PLOS Pathogens provides insight into how this happens.

Science Daily

A protein in Salmonella inactivates mast cells — critical players in the body’s fight against bacteria and other pathogens — rendering them unable to protect against bacterial spread in the body, according to researchers at Duke Medicine and Duke-National University of Singapore (Duke-NUS).

Science Daily

Scientists have used a new method to map the response of every salmonella gene to conditions in the human body, providing new insight into how the bacteria triggers infection.

Science Daily

Scientists at the Stanford University School of Medicine have revealed that formerly overlooked sites deep inside the nose may be reservoirs for Staphylococcus aureus, a major bacterial cause of disease.

Research – Pecan Shell Inhibition of Listeria

Wiley Online LaboratoryEurofins Food Testing UK

Growers and processors of USDA certified organic foods are in need of suitable organic antimicrobials. The purpose of the research reported here was to develop and test natural antimicrobials derived from an all-natural by-product, organic pecan shells. Unroasted and roasted organic pecan shells were subjected to solvent free extraction to produce antimicrobials that were tested against Listeria spp. and L. monocytogenes serotypes to determine the minimum inhibitory concentrations (MIC) of antimicrobials. The effectiveness of pecan shell extracts were further tested using a poultry skin model system and the growth inhibition of the Listeria cells adhered onto the skin model were quantified. The solvent free extracts of pecan shells inhibited Listeria strains at MICs as low as 0.38%. The antimicrobial effectiveness tests on a poultry skin model exhibited nearly a 2 log reduction of the inoculated cocktail mix of Listeria strains when extracts of pecan shell powder were used. The extracts also produced greater than a 4 log reduction of the indigenous spoilage bacteria on the chicken skin. Thus, the pecan shell extracts may prove to be very effective alternative antimicrobials against food pathogens and supplement the demand for effective natural antimicrobials for use in organic meat processing.

Research – Listeria in Cheese sites – E.coli O157/Salmonella on Spinach

Science Direct

Inhibition of Escherichia coli O157:H7 and Salmonella enterica on spinach and identification of antimicrobial substances produced by a commercial Lactic Acid Bacteria food safety intervention
The microbiological safety of fresh produce is of concern for the U.S. food supply. Members of the Lactic Acid Bacteria (LAB) have been reported to antagonize pathogens by competing for nutrients and by secretion of substances with antimicrobial activity, including organic acids, peroxides, and antimicrobial polypeptides. The objectives of this research were to: (i) determine the capacity of a commercial LAB food antimicrobial to inhibit Escherichia coli O157:H7 and Salmonella enterica on spinach leaf surfaces, and (ii) identify antimicrobial substances produced in vitro by the LAB comprising the food antimicrobial. Pathogens were inoculated on freshly harvested spinach, followed by application of the LAB antimicrobial. Treated spinach was aerobically incubated up to 12 days at 7 °C and surviving pathogens enumerated via selective/differential plating. l-Lactic acid and a bacteriocin-like inhibitory substance (BLIS) were detected and quantified from cell-free fermentates obtained from LAB-inoculated liquid microbiological medium. Application of 8.0 log10 CFU/g LAB produced significant (p < 0.05) reductions in E. coli O157:H7 and Salmonella populations on spinach of 1.6 and 1.9 log10 CFU/g, respectively. It was concluded the LAB antimicrobial inhibited foodborne pathogens on spinach during refrigerated storage, likely the result of the production of metabolites with antimicrobial activity.

Mary Ann Leibert

Collaborative Survey on the Colonization of Different Types of Cheese-Processing Facilities with Listeria monocytogenes

Cross-contamination via equipment and the food-processing environment has been implicated as the main cause of Listeria monocytogenes transmission. The aim of this study, therefore, was to determine the occurrence and potential persistence of L. monocytogenes in 19 European cheese-processing facilities. A sampling approach in 2007–2008 included, respectively, 11 and two industrial cheese producers in Austria and the Czech Republic, as well as six Irish on-farm cheese producers. From some of the producers, isolates were available from sampling before 2007. All isolates from both periods were included in a strain collection consisting of 226 L. monocytogenes isolates, which were then typed by serotyping and pulsed-field gel electrophoresis (PFGE). In addition, metabolic fingerprints from a subset of isolates were obtained by means of Fourier-transform infrared (FTIR) spectroscopy. PFGE typing showed that six processing environments were colonized with seven persistent PFGE types of L. monocytogenes. Multilocus sequence typing undertaken on representatives of the seven persisting PFGE types grouped them into distinct clades on the basis of country and origin; however, two persistent strains from an Austrian and an Irish food processor were shown to be clonal. It was concluded that despite the fact that elaborate Hazard Analysis and Critical Control Point concepts and cleaning programs are applied, persistent occurrence of L. monocytogenes can take place during cheese making. L. monocytogenes sanitation programs could be strengthened by including rapid analytical tools, such as FTIR, which allow prescreening of potentially persistent L. monocytogenes contaminants.

 

UK – Food Standards Agency Recall – Possible Clostridium Issue

FSAfood_standards_agency_logo

Village Park Meats Ltd recalls batches of its vacuum packed, cooked, sliced meats due to inadequate controlling factors to prevent growth of Clostridium botulinum.

During an inspection it was established that an extended shelf-life was being applied to all vacuum packed cooked meats, despite the fact that production records indicated a 10-day shelf-life was being applied.  Due to inadequate controlling factors to prevent growth and toxin production of Clostridium botulinum, a recall is being carried out as a precautionary measure. Village Park Meats Ltd has recalled all affected batches detailed in the link above.

Research Articles – Raw Milk – Antimicrobial Film Coatings to Control Listeria – E.col O157 and Salmonella Control by MAP and Polylysine – Gut Flora and Listeria Infection

Food Poisoning Bulletin

One of every six people who drinks raw milk gets food poisoning, according to a new study from officials at the Minnesota Department of Health.  That percentage is much higher than the number of cases reported in relation to outbreaks associated with raw milk and, researchers say, it’s increasing even as some states push to relax raw milk regulations.

Science Direct

Edible antimicrobial coating solutions incorporating chitosan, lauric arginate ester (LAE) and nisin were developed to reduce foodborne pathogen contamination on ready-to-eat (RTE) meats. RTE deli meat samples were directly coated with the solutions, or treated with solution-coated polylactic acid (PLA) films. The antimicrobial efficacy of the coatings and films against Listeria innocua inoculated onto the surface of RTE meat samples was investigated. Antimicrobial coatings with 1.94 mg/cm2 of chitosan and 0.388 mg/cm2 of LAE reduced L. innocua by ca. 4.5 log CFU/cm2. Nisin (486 IU/cm2) showed less effectiveness than LAE (0.388 mg/cm2) and addition of nisin to the antimicrobial coatings or films containing LAE (0.388 mg/cm2) did not enhance the total antimicrobial effectiveness. Combining antimicrobial coatings or films with flash pasteurization (FP), which uses short burst of steam under pressure, further reduced L. innocua, achieving over a 5 log reduction. There was no significant difference in the effectiveness of antimicrobial films versus the coatings (p > 0.05). These data show the potential use of antimicrobial packaging alone, or in combination with FP, in preventing foodborne illness due to post-processing contamination of RTE meat products.

Science Direct

Escherichia coli O157:H7 and Salmonella spp. often contaminate fresh beef. In Japan, an E coli outbreak caused by raw beef made 181 people ill and 5 individuals dead in 2011. Responding to this outbreak, an effective sterilization method for fresh beef is expected to be developed. In this study, ε-polylysine combined with CO2-packaging method was examined for controlling these pathogens in fresh beef. At an incubation temperature of 4 °C, approximately 4.3 log and 2.4 log reduction in bacterial numbers were observed after 7-day incubation for E. coli O157:H7 and Salmonella, respectively, in ε-polylysine-added beef. When effectiveness of CO2-packaging combined with ε-polylysine was investigated, CO2 did not have additional inhibiting effect on bacterial growth compared to only-ε-polylysine-treated samples when incubated at 4 °C. However, effectiveness of CO2 was observed when incubated at 10 °C where approximately 2.9 log and 4.4 log reduction in E. coli cell numbers were observed in only-ε-polylysine-treated samples and polylysine- and CO2-treated group, respectively, and approximately 1.7 log and 3.5 log reduction in Salmonella cell numbers were observed in only-ε-polylysine-treated samples and polylysine and CO2-treated group, respectively. This study confirmed that ε-polylysine or ε-polylysine combined with CO2 packaging are effective in preventing foodborne diseases caused by raw beef.

Food Poisoning Bulletin

The army of microbes that resides in the human gut may provide a powerful defense against Listeria infection, according to a study published in mBio, the online open-access journal of the American Society for Microbiology. The study, by a team of French researchers, shows that mice with germ-free intestines are more susceptible to Listeria infection than mice with the conventional intestinal microbes.

 

USA – Texas – Shigella and Botulism Outbreaks

Shigella BlogShigella_stool

Shigella outbreak continues to hit Grayson County hard. Health Department officials say new cases are being reported every day.

News 12 last reported there were 36 cases just before Thanksgiving. But, in just 13 days that number has jumped to 61 confirmed cases in Grayson County.

A command center has been set up at the Health Department, where they say employees are working to stop Shigella from spreading.

Botulism Blog

On Friday, the Health Department was informed of the first potential case here in Amarillo. They soon began investigating and discovered three other possible cases.

Two of the patients matched the criteria and were given the antitoxin. Doctors say they are slowly improving.

All four patients are adults and are currently hospitalized.

“We’ve got a small group of people who know each other in some manner, we hope that there are no other cases, but we just want to do our due diligence and make sure that we are protecting our community by providing information,” Casie Stoughton who is the Assistant Director of the City of Amarillo Public Health Department.

Research – Information Clostridium botulinum

Food Poisoning Journal

Botulism is a rare, life-threatening paralytic illness caused by neurotoxins produced by an anaerobic, gram-positive, spore-forming bacterium, Clostridium botulinum. Unlike Clostridium perfringens, which requires the ingestion of large numbers of viable cells to cause symptoms, the symptoms of botulism are caused by the ingestion of highly toxic, soluble exotoxins produced by C. botulinum while growing in foods.

UK – FSA – Call For Tender – Effectiveness of Surface Treatment in Reducing Microbiological Contamination

FSAfood_standards_agency_logo

The Food Standards Agency is inviting tenders to carry out research on the effectiveness of surface treatment in reducing microbiological contamination of meat. This project only applies to meat intended for the production of raw or lightly cooked food.

RASFF Alerts – Aflatoxin -Pistachio – Ginger – Groundnuts – Dried Figs – Peanuts

RASFF -aflatoxins (B1 = 15.9; Tot. = 18.1 µg/kg – ppb) in pistachio kernels from Afghanistan, via Turkey in Italy

RASFF -aflatoxins (B1 = 10.7; Tot. = 30.8 µg/kg – ppb) in organic ginger from India in Germany

RASFF-aflatoxins in blanched groundnuts from China in France

RASFF – aflatoxins (B1 = 0.5 / B1 = 38.3 µg/kg – ppb) in dried figs from Turkey in France

RASFF-aflatoxins (B1 = 38.6; Tot. = 43.6 µg/kg – ppb) in dried figs pulled from Turkey in France

RASFF-aflatoxins (B1 = 25.2; Tot. = 29.0 / B1 = 23.7; Tot. = 27.5 µg/kg – ppb) in peanut kernels from China in Cyprus