Category Archives: Methods

Research – Listeria’s Resistance to Disinfectants

University of Veterinary Science- ViennaEurofins Food Testing UK

Listeria poses a significant risk to human health. The main transmission route involves meat and dairy products, so it is important to treat dairies and food-processing plants regularly with disinfectants to kill bacteria. Unfortunately, listeria is developing resistance to the compounds that are most frequently used. Recent work in the group of Stephan Schmitz-Esser at the University of Veterinary Medicine, Vienna (Vetmeduni Vienna) has uncovered the mechanism for listeria’s resistance to one such agent, benzalkonium chloride. The findings have been published in the online journal Plos One.

 

Research – Practical Considerations for the Interpretation of Microbial Testing Results Based on Small Numbers of Samples

Liebert Online

While adequate, statistically designed sampling plans should be used whenever feasible, inference about the presence of pathogens in food occasionally has to be made based on smaller numbers of samples. To help the interpretation of such results, we reviewed the impact of small sample sizes on pathogen detection and prevalence estimation. In particular, we evaluated four situations commonly encountered in practice. The first two examples evaluate the combined impact of sample size and pathogen prevalence (i.e., fraction of contaminated food items in a given lot) on pathogen detection and prevalence estimation. The latter two examples extend the previous example to consider the impact of pathogen concentration and imperfect test sensitivity. The provided examples highlight the difficulties of making inference based on small numbers of samples, and emphasize the importance of using appropriate statistical sampling designs whenever possible.

Research – Norovirus – Surfaces – Handlers – DIsinfectants

Ingenta ConnectEurofins

Human infective noroviruses (NoVs) are a worldwide leading cause of foodborne illness and are frequently spread via infected food handlers preparing and manipulating food products such as deli sandwiches. The objective of the current study was to determine the efficiencies whereby NoV could be transferred between surfaces associated with the preparation of manually prepared foods such as deli sandwiches. Nonfood surfaces included gloves and stainless steel discs, and boiled ham, lettuce, and a sandwich bun were the ingredients of the deli sandwich. Both NoV GII.4 and the murine NoV 1 (MNV-1, a cultivable human NoV surrogate) were included in the presented study. Transfer of NoV GII.4 and MNV-1 between surfaces was performed by pressing an inoculated donor surface against an acceptor surface. To evaluate the effect of subsequent contact, donor surfaces were pressed a second time to an identical acceptor surface. Subsequently, NoV GII.4 and MNV-1 were detected using real-time reverse transcription PCR assays and plaque assays, respectively. Transfer of both viruses from gloves to stainless steel was inefficient, and virus transfer from food products to stainless steel occurred with more variability for NoV GII.4 than for MNV-1. Virus transfer from the stainless steel discs to the gloves was substantially more efficient than from the gloves to the stainless steel. NoV GII.4 and MNV-1 transfer from food products to the gloves occurred with varying efficiencies, although this variation was more evident for NoV GII.4. The MNV-1 inoculum was significantly less efficiently transferred to the acceptor surface at the second contact, which was not the case for NoV GII.4. The obtained transfer efficiency data may provide insights into the transfer of NoV during preparation of foods and can be included in risk assessment models describing the transmission of NoVs in this context.

Ingenta Connect

Human noroviruses (HuNoVs) are the most common cause of acute viral gastroenteritis worldwide and are a leading cause of foodborne disease. Their environmental persistence and purported resistance to disinfection undoubtedly contribute to their success as foodborne disease agents. The purpose of this study was to compare the efficacy of three commonly used disinfectant active ingredients against representative HuNoV strains and cultivable surrogates. Ethanol (50, 70, and 90%), sodium hypochlorite (5, 75, 250, 500, and 1,000 ppm), and a quaternary ammonium compound blend (at 0.1×, 1.0×, and 10× concentrations) were evaluated against two norovirus (NoV) genogroup II strains (GII.2 and GII.4) and two surrogates (feline calicivirus [FCV] and murine norovirus [MNV-1]). Virucidal suspension assays (30-s exposure) were conducted in accordance with ASTM International standard E-1052. Virus inactivation was quantified using reverse transcription quantitative PCR targeting the ORFI-ORFII junction (HuNoV), the RNA polymerase region (MNV-1), or the ORFI region (FCV); infectivity assays were also performed for MNV-1 and FCV. The two HuNoV strains and FCV were relatively resistant to ethanol (<0.5 log inactivation) irrespective of concentration, but MNV-1 was much more susceptible (log inactivation, ∼2.0 log at higher ethanol concentrations). Both HuNoV strains were more resistant to hypochlorite than were either of the animal surrogates, with the human strains requiring ≥500 ppm of hypochlorite to achieve statistically significant reduction (≥3.0 log) in virus concentration. All four viruses were resistant to inactivation (<0.5-log reduction) using the quaternary ammonium compound formulation at all concentrations tested. This study is novel in that it clearly demonstrates the relative ineffectiveness of common active disinfectant ingredients against HuNoV and highlights the fact that the cultivable surrogates do not always mimic HuNoV strains.

Research – Olive Powder Combatting E.coli in Hamburgers

FeedStuffs FoodLink

The potential of olive powder to keep foods safe to eat is getting a fresh look from Albany chemist Mendel Friedman and colleagues at the University of Arizona-Tucson.

An olive processing co-product, olive powder was one of about two dozen plant extracts, spices, and herbs that the team evaluated for their potential to combat Escherichia coli O157:H7 and to retard formation of heterocyclic amines during cooking of hamburger patties.

E. coli O157:H7 is a leading cause of food sickness in the U.S. and is blamed for more than 73,000 cases of illness annually. In recent years, many E. coli outbreaks have been traced back to ground beef and have led to the introduction of stringent new food safety rules designed to reduce the occurrence of this microbe, and six of its relatives, in meats, poultry, and other foods.

The ability of olive extracts to kill foodborne pathogens has been reported in earlier studies conducted at Albany, Tucson, and elsewhere. However, the E. coli and amines study, reported in a 2012 issue of the Journal of Agricultural and Food Chemistry, may be the first to show olive powder’s performance in concurrently suppressing three targets of concern — two major amines and a pervasive E. coli.

UK – FSA Annual Food Incidents Report

FSA food_standards_agency_logo

The Food Standards Agency has today published its latest Annual Report of Food Incidents. The report highlights the wide range of incidents managed by the Food Standards Agency during 2012.

Last year, a total of 1,604 food and environmental contamination incidents in the UK were reported to and investigated by the FSA. This figure was 110 down on 2011 but higher than in many previous years. The three largest contributors to these incidents were microbiological contamination (20%), environmental contamination (15%) and natural chemical contamination (13%).

One of the valuable roles played by the report is providing insight into why certain types of incident have increased. For example, FSA investigations show a recent rise in a certain type of salmonella was mostly the result of paan leaves imported from Bangladesh. Similarly, the number of allergen-related incidents appears to have risen by more than half since 2010. Statistics suggest, however, that legislative changes relating to gluten may have been a major contributory factor.

The report also shows a rise in the number of whistleblowers who contacted the FSA during the year. A total of 81 cases originated from whistleblowers during 2012 – up from 54 the previous year.

Catherine Brown, Chief Executive of the Food Standards Agency, said: ‘We hope that this annual report encourages food businesses and consumers to notify us promptly of incidents and of any other potentially-useful intelligence they have. This will enable us to act swiftly to protect the public and the food industry and, in so doing, increase public confidence in food safety.’

The data released today does not include the incidents of horsemeat contamination that came to light in the first half of 2013, as these occurred outside of the scope of the report. All incidents notified to the FSA are reviewed, and in the case of horsemeat the FSA has commissioned an additional independent external review of how it responded. This is due to report shortly.

Catherine Brown said: ‘Although the horsemeat incident occurred outside the scope of this report, I would like to highlight the resolve with which the FSA responded. Working closely with other Government departments and the food industry, the Agency ensured that 6,000 tests of frozen products were carried out within three weeks – far more than any other EU member state. The UK was also the first country to submit a dossier to Europol and the first country to make arrests.

‘By responding so quickly, we were able to reassure the public that more than 99% of the tests undertaken in the UK contained no horse DNA at the level of 1% or above, and that there was no threat to public health.’

 

USA – CDC Report on Listeria 2009-2011

CDCE.coli O157

This report details the epidemiology of invasive listeriosis, which often leads to bacteremia, meningitis, hospitalization, fetal loss, and death, and calls for actions that could protect the most vulnerable populations. Older adults and pregnant women, particularly pregnant Hispanic women, are at much higher risk than the population at large, as are persons with weakened immunity (2). Preventing infections in these populations can have substantial impact in averting these outcomes. Older adults and persons with weakened immunity, as well as infants and young children, are also prone to many other foodborne illnesses, including campylobacteriosis, salmonellosis, and Shiga toxin–producing E. coli infections (4). Accounting for underdiagnosis and underreporting, an estimated 1,662 cases of listeriosis occur each year (5). No progress in reducing the overall incidence of listeriosis has occurred in over a decade (3,4); renewed prevention efforts are needed from farm to table.

 

Research – Faster Salmonella ID – Mathematical Model Food Safety

Science CodexiStock_000008493122Small

A new approach may be able to reduce by more than half the time it takes health officials to identify Salmonella strains, according to researchers in Penn State’s College of Agricultural Sciences.

The finding may significantly speed up the response to many outbreaks of foodborne illness, allowing epidemiological investigators to identify the exact strains of Salmonella that make people sick and to more quickly find — and eliminate — the source of the disease.

Working in collaboration with Carol Sandt, a scientist with the Bureau of Laboratories, Division of Clinical Microbiology in the Pennsylvania Department of Health and Eija Trees, a microbiologist at the U.S. Centers for Disease Control and Prevention, Shariat used Salmonella samples supplied by the state health department. Results of the study were published online in May in the Journal of Clinical Microbiology.

“Compared to the current method being used nationally and internationally to subtype Salmonella, our approach is faster,” Shariat said. “The significance of that is you need to trace the source of an outbreak as quickly as you can before you start insisting on restaurant and farm closures. It is important to pinpoint the source of the bacteria — the quicker you do that the quicker you can respond to the disease outbreak.”

Ingenta Connect

This document describes the development of a tool to manage the risk of the transportation of cold food without temperature control. The tool uses predictions from ComBase predictor and builds on the 2009 U.S. Food and Drug Administration Model Food Code and supporting scientific data in the Food Code annex. I selected Salmonella spp. and Listeria monocytogenes as the organisms for risk management. Salmonella spp. were selected because they are associated with a wide variety of foods and grow rapidly at temperatures >17°C. L. monocytogenes was selected because it is frequently present in the food processing environment, it was used in the original analysis contained in the Food Code Annex, and it grows relatively rapidly at temperatures <17°C. The suitability of a variety of growth models under changing temperature conditions is largely supported by the published literature. The ComBase predictions under static temperature conditions were validated using 148 ComBase database observations for Salmonella spp. and L. monocytogenes in real foods. The times and temperature changes encompassed by ComBase Predictor models for Salmonella spp. and L. monocytogenes are consistent with published data on consumer food transport to the home from the grocery store and on representative foods from a wholesale cash and carry food service supplier collected as part of this project. The resulting model-based tool will be a useful aid to risk managers and customers of wholesale cash and carry food service suppliers, as well as to anyone interested in assessing and managing the risks posed by holding cold foods out of temperature control in supermarkets, delis, restaurants, cafeterias, and homes.

USA Research – Report on Anitmicrobial Resistance

Food Poisoning Bulletincocci

The Center for Science in the Public Interest (CSPI) has released a white paper titled “Antibiotic Resistance in Foodborne Pathogens.” The paper details information about more than 55 foodborne illness outbreaks since 1973. In 31 of those outbreaks, the bacteria were resistant to five or more antibiotics. Forty-eight of the 55 outbreaks were caused by Salmonella bacteria.

The foods most likely associated with antibiotic resistant bacteria included dairy products, ground beef, and poultry; those foods were associated with 31 out of 55 outbreaks. The paper states that the two populations that are most at risk of foodborne illness are children and immune-compromised people.

CSPI is critical of the FDA’s approach to dealing with this problem. In April 2012, the FDA issued guidance documents for industry that just “encourage” drug companies to change labeling on antibiotics used in animals to prevent their non-therapeutic use for growth promotion or feed efficiency. Scientists, including those at Johns Hopkins Center for a Livable Future, say that the government should issue regulations about antibiotic use that have enforcement capability. Furthermore, CSPI and other groups want legislation such as “The Preservation of Antibiotics for the Medical Treatment Act” or PAMTA, passed into law.

RASSF Alerts – Salmonella Beef – Pork Sausage – Chicken – Cotton Seeds – Soyabean Meal -Feed

RASFF – Salmonella infantis (presence /25g) in beef trimmings from Poland, via Germany in Sweden

RASSF – Salmonella (presence /25g) in dry pork sausage from France

RASSF – Salmonella spp. (present /25g) in frozen chicken (Gallus domesticus) from Brazil in the Netherlands

RASSF – Salmonella spp. (present in 3 out of 5 samples /25g) in cotton seeds from Ghana in Italy

RASSF – Salmonella Derby (presence /25g) in soybean meal from India, via Italy in Austria

RASFF – Salmonella Livingstone (presence /25g) in supplementary feed for dogs and cats from Germany

RASFF – Salmonella (present /25g) in soybean meal from Argentina in Poland

USA – FDA – Cookie Mixes Recall – Salmonella

FDASalm

Eco-Cuisine of Boulder, Colorado is recalling all lots of T3314 Basic Brownie
Mix, T3333 Betty Brownie Mix with Vanilla, T3388 Ground Beef Style Quick Mix, T3394 Sausage Style Quick Mix, T3416 Chocolate Cookie Mix, T3417 Lemon Muffin Mix, and T3418 English Scone Mix, CM25COOK Basic Cookie Mix 25 lb. bag, CM25MUFF  Basic Muffin Mix 25 lb. bag, CM25SCON Basic Scone Mix 25 lb. Bag, because it has the potential to be contaminated with Salmonella, an organism which can cause serious and sometimes fatal infections in young children, frail or elderly people, and others with weakened immune systems.
Healthy persons infected with Salmonella often experience fever,
diarrhea (which may be bloody), nausea, vomiting and abdominal pain. In rare
circumstances, infection with Salmonella can result in the organism
getting into the bloodstream and producing more severe illnesses such as
arterial infections (i.e., infected aneurysms), endocarditis and arthritis.