New biosensor enables rapid detection of Listeria

A Texas A&M AgriLife Research engineer and a Florida colleague have developed a biosensor that can detect listeria bacterial contamination within two or three minutes.

listeria4“We hope to soon be able to detect levels as low as one bacteria in a 25-gram sample of material – about one ounce,” said Dr. Carmen Gomes, AgriLife Research engineer with the Texas A&M University department of biological and agricultural engineering.

The same technology can be developed to detect other pathogens such as E. coli O157:H7, she said. But listeria was chosen as the first target pathogen because it can survive even at freezing temperatures. It is also one of the most common foodborne pathogens in the world and the third-leading cause of death from food poisoning in the U.S.

“It can grow under refrigeration, but it will grow rapidly when it is warmed up as its optimum growth temperature ranges from 30 to 37 degrees Celsius — 86 to 98 degrees Fahrenheit,” Gomes said. “This makes it a particular problem for foods that are often not cooked, like leafy vegetables, fruits and soft cheeses that are stored under refrigeration.”

Currently, the only means of detecting listeria bacteria contamination of food requires highly trained technicians and processes that take several days to complete, she said. For food processing companies that produce and ship large quantities of foodstuff daily, listeria contamination sources can be a moving target that is often missed by current technology.

Children hospitalized buthealth types refuse to release details: UK E. coli outbreak

An outbreak of E coli has been identified in Dorset after a child was confirmed to be infected with the disease.

claudia.e.coli.petting.zoo.may.14The child is one of two from the county who are currently in hospital with hemolytic uremic syndrome (HUS), a complication of E coli infection.

Public Health England, which is also carrying out tests on three further children, has refused to divulge any details about the location of the outbreak or where the children are from.

Last year 10 people in Dorset were affected by the disease between July and November.

Control of E. coli O157 on beef with bacteriophages

Efficacy of four bacteriophages (phages) and a cocktail for biocontrol of Escherichia coli O157 was assessed on beef samples stored at 4, 22 and 37 °C.

lunar.moduleSamples (3 × 3 × 1 cm) were contaminated withE. coli O157 (104 CFU/cm2) and treated with single phages: T5-like (T5), T1-like (T1), T4-like (T4) and O1-like (O1), or a cocktail at two titers: multiplicity of infection (MOI) = 1000 and MOI = 10. In contrast to previous studies, use of virucidal solution prevented over-estimation of phage efficacy. Irrespective of temperature and MOIs, T5 was most (P < 0.001) and O1 least (P < 0.05) effective for biocontrol of E. coliO157, with relative efficacy of other phages temperature dependent. At 4 °C, T1 (P < 0.05) and cocktail (P < 0.001) were more effective than T4. In contrast, T4 was equally (P = 0.08, at 37 °C) or less effective (P = 0.003, at 22 °C) than T5. Phages were more effective (P < 0.001) against E. coli O157 at warmer temperatures and high MOI.

As the beef supply chain includes hours of storage or transport at temperatures near 4 °C, this study demonstrates phages could significantly reduce E. coli O157 during this period.

Control of Escherichia coli O157 on beef at 37, 22 and 4 °C by T5-, T1-, T4-and O1-like bacteriophages

Food Microbiology Volume 51, October 2015, Pages 69–73, doi:10.1016/j.fm.2015.05.001

Liu, Y.D. Niu, R. Meng, J. Wang, J. Li, R.P. Johnson, T.A. McAllister, K. Stanford

http://www.sciencedirect.com/science/article/pii/S0740002015000878

E. coli in pigs: Real-time PCR

Escherichia coli is found naturally in the intestinal flora of pigs and, under certain circumstances, it causes a clinical picture of colibacillosis, a disease that can manifest itself as different conditions involving neonatal diarrhoea, post-weaning diarrhoea, oedema disease, septicaemia, etc…

pig-in-shock1Proper diagnosis includes a thorough anamnesis, a correct selection of samples and a complete differential diagnosis supported by various techniques. The mere detection of pathogenic strains does not justify the disease in every case due to the often finding of asymptomatic carriers. Identifying relevant virulence strains and differentiating them from other normal gut flora is a highly topical diagnostic challenge. And the real time PCR (qPCR) applied to the detection of virulence factors (VFs) of E. coli has rised up as a powerful tool able to generate useful information.

Based on the extraction of nucleic acids from different biological matrices (culture, faeces, intestinal or rectal swab), qPCR assays recognize specific genomic regions of E. coli encoding different VFs. In this work, each trial was designed to detect a different VF. An additional qPCR (ECCO) was used to confirm the presence of E. coli in the samples and to ensure that all stages of the technique had been performed correctly. qPCR is a qualitative assay, but it’s also quantitative (Figure 1), which is a significant advantage over its predecessor, conventional PCR.

The smaller the Cq value, the higher the initial concentration of the parameter studied in the sample.

Evaluation of virulent strains in colibacillosis was traditionally achieved by an initial microbiological culture, then isolation of colonies of E. coli and subsequent characterization of their VFs. The main disadvantage of this method is that the analysis can only be performed on a limited number of selected isolates, the accuracy of the diagnosis relying on the assumption that these are representative in the total population of E. coli in the sample studied. This way, there is a risk of omitting non-majority populations of E. coli that are, however, clinically relevant.

qPCR provides the possibility of analysing the VFs directly on the clinical sample. This methodology avoids intermediate culture steps and their respective determinations on each of the different selected isolates, leading to considerable savings in time and costs. Given the quantitative nature of the technique, a relationship can be established between the number of copies detected for a specific virulence gene and the total population of E. coli in the sample. This way we could interpret the possibility of isolating a strain with a particular combination of VFs.

This methodology has certain limitations due to the indeterminate number of copies of the individual genes encoding each VF within different bacterial populations. However, it meets the proposed objective: to assess the possibility of finding E. coli with a particular combination of VFs in the sample.

In conclusion, qPCR applied directly to clinical samples provides substantial savings of time and resources, as well as information leading to an interpretation providing solutions for the sensitive diagnosis of porcine colibacillosis.

Canada, how long does it take to write a PR? 13 sick with E. coli infections and possible link to leafy greens

The leafy greens cone of silence continues to silence or impair epidemiology across North America.

leafy.green.lettuceThe Public Health Agency of Canada says today that 13 people across Canada were sickened with E. coli O157:H7 with a possible link to leafy greens, and that the investigation concluded on May 12, 2015.

Two weeks is a long time to get approval for a simple press release.

“Although leafy greens were identified as a possible source of illness, a specific source of the outbreak could not be confirmed.

“During the investigation, exposure to leafy greens was identified as a possible source of illness. Leafy greens can include all varieties of lettuces and other green leaf vegetables such as kale, spinach, arugula, or chard. The Canadian Food Inspection Agency conducted an investigation into leafy greens, however no specific food products were identified as the source of the outbreak.”

And the usual boilerplate:

waynes-world-monkeys-might-fly-out--e1297873880696“Canadians are reminded to always follow safe food handling practices to avoid illness. Wash your hands thoroughly before preparing or eating food. Wash raw fruits and vegetables thoroughly with clean, safe running water before you prepare and eat them.”

Yup, 13 people from Alberta to Newfoundland got sick with the same E. coli because of bad handwashing (not).

Hamburgers and Memorial Day

As I devoured a 160F tip-sensitive thermometer verified hamburger this morning while watching Tampa beat New York in hockey playoffs, I was reminded that NY Times foodie Sam Sifton took 1,600 words last year to describe how to cook the ‘perfect burger’ and no mention of thermometers.

The Times wonders why it’s losing readers (and please, stop sending me the daily offers to resubscribe for almost nothing, it’s embarrassing).

Food porn always trumps food safety, until someone gets sick.

Bask in Memorial Day, my fellow U.S. citizens, remember those who gave and continue to give, and try not to make anyone barf.

hamburger-safe and unsafe-thumb-450x138-175

Raw is risky: E. coli in veal tartare sickened 7

An Escherichia coli O157:H7 outbreak occurred in 2013 that was associated with the consumption of beef and veal tartares in the province of Quebec. This report describes the results of the ensuing investigation.

veal.tartareMaterials and Methods: As the outbreak was identified, all individuals in the province of Quebec affected with the same strain of E. coli O157:H7 as defined by pulsed-field gel electrophoresis were interviewed using a standardized questionnaire. Cases reported from other provinces in Canada were interviewed by their public health authorities and the results were reported to the Quebec public health authorities. Microbiological and environmental investigations were conducted by the Sous-ministériat à la santé animale et à l’inspection des aliments du Ministère de l’Agriculture, des Pêcheries et de l’Alimentation du Québec, by the Ville de Montréal’s Food Inspection Branch, and by the Canadian Food Inspection Agency at the restaurants, suppliers, and slaughterhouses identified.

Results: In total, seven individuals in three different Canadian provinces became ill following infection with the same outbreak strain of E. coli O157:H7. Two cases were hospitalized and one had severe hemolytic uremic syndrome. No deaths were reported. Two restaurant locations serving different tartare meals including, beef, veal, salmon, tuna, and duck were identified as potential sources of the outbreak. No deficiencies at the restaurant locations were observed during inspections by food inspectors.

Conclusions: The risk of consuming tartare can be lowered when basic hygienic rules are followed, temperature is strictly controlled, and fresh meat is used. However, even if handling, chopping, and temperature control during storage of the meat are considered adequate, tartare is a raw product and the risk of contamination is present. Consumers should be advised that consuming this product can lead to serious illness. 

Escherichia coli O157:H7 outbreak associated with the consumption of beef and veal tartares in the province of Quebec, Canada in 2013

Foodborne Pathogens and Disease

Gaulin Colette, Ramsay Danielle, Catford Angela, and Bekal Sadjia

http://online.liebertpub.com/doi/abs/10.1089/fpd.2014.1919

 

Wash health officials limit fair events after E. coli outbreak

State health officials have restricted events at the Lynden, Whatcom County, fairgrounds, where an outbreak of dangerous E. coli sickened dozens last month, to prevent potential spread of additional illness.

petting.zoo.1.apr.13Dr. Scott Lindquist, the Washington state epidemiologist for communicable diseases, said the move is a precaution while county, state and federal officials determine the source of the outbreak that sent at least eight people to hospitals.

“We’re recommending they not have any more events until we’ve finished our investigation,” Lindquist said.

The request immediately affects a dog show planned for Saturday by the Mount Baker Kennel Club, expected to attract 800 canines and more than 2,000 people to the Northwest Washington Fair & Event Center.

Stiles said she understood and applauded health officials’ efforts to make sure no one else got sick at the site where more than 1,300 first-graders were exposed to Shiga toxin-producing E. coli O157: H7.

The outbreak followed the annual Milk Makers Fest held April 21-23. At least 15 people contracted lab-confirmed infections, with eight hospitalized and three who developed hemolytic uremic syndrome, a life-threatening complication of E. coli illness.

About 30 others are still being tested. Whatcom County health officials originally estimated as many as 47 people were sickened, but they’ve changed the way the cases are defined.

What’s the frequency Kenneth: USDA finalizes rule to require labeling of mechanically tenderized beef

After initially saying a rule would be delayed until 2018, the U.S. Department of Agriculture today announced new labeling requirements for raw or partially cooked beef products that have been mechanically tenderized.

needle.tenderize.cr, restaurants, and other food service facilities will now have more information about the products they are buying, as well as useful cooking instructions so they know how to safely prepare them.

“Labeling mechanically tenderized beef products and including cooking instructions on the package are important steps in helping consumers to safely prepare these products,” said Deputy Under Secretary Al Almanza. “This common sense change will lead to safer meals and fewer foodborne illnesses.”

Maybe.

And if it’s common sense, why did it take until today?

These new requirements will become effective in May 2016, or one year from the date of the rule’s publication in the Federal Register. Because of the public health significance of this change, FSIS is accelerating the effective date instead of waiting until the next Uniform Compliance Date for Food Labeling Regulations, which is January 1, 2018.

Product tenderness is a key selling point for beef products. To increase tenderness, some cuts of beef are tenderized mechanically by piercing them with needles or small blades in order to break up tissue. This process, however, can introduce pathogens from the surface of the cut to the interior, making proper cooking very important.

needle.tenderize.beef.HC.feb.14The potential presence of pathogens in the interior of these products means they should be cooked differently than intact cuts. FSIS is finalizing these new labeling requirements because mechanically tenderized products look no different than intact product, but it is important for consumers to know that they need to handle them differently.

Under this rule, these products must bear labels that state that they have been mechanically, blade or needle tenderized. The labels must also include validated cooking instructions so that consumers know how to safely prepare them. The instructions will have to specify the minimum internal temperatures and any hold or “dwell” times for the products to ensure that they are fully cooked.

Since 2000, the Centers for Disease Control and Prevention has received reports of six outbreaks attributable to needle or blade tenderized beef products prepared in restaurants and consumers’ homes. Failure to thoroughly cook a mechanically tenderized raw or partially cooked beef product was a significant contributing factor in each of these outbreaks. FSIS predicts that the changes brought about by this rule could prevent hundreds of illnesses every year.

Maybe.

About 11 percent, or 2.6 billion pounds, of beef products sold in the U.S. have been mechanically tenderized, according to USDA data.

Australian farmer prosecuted for supplying unpasteurised milk under cow share scheme

Mark Tyler of South Australia says the raw milk distributed from his 50 or so cows at his Willunga Hill property to shareholders who paid $30 plus a fortnightly boarding fee, then picked up their milk regularly from the farm, is safe.

colbert.raw.milkA judge didn’t agree.

The Tylers could face a fine of up to $50,000 for breaching food regulations.

Raw milk sales are illegal and the South Australian Government argued the couple’s “cow share” arrangement constituted a sale under the Food Act.

“We’ve got over 2,000 people drinking it every day, really no one’s having an issue,” said Tyler.

“There’s virtually no proven cases of raw milk causing illness in people.”

Nosestretcher.

There has been a push by legislators to crack down on raw milk sales across Australia since a three-year-old Victorian boy died last year.