Every hour of every day people around the world are living with and working to resolve food safety issues. Here is a sampling of current headlines for your consumption, brought to you today with the support of iwaspoisoned.com.
Killing Salmonella with heat
The most economical way to kill bacteria that cause common food-borne illnesses — mostly caused by Salmonella enterica — is heat, but, the mechanisms that kill Salmonella at lower temperatures were not fully understood until now, according to a team of researchers at Penn State.
Aida Ebrahimi, assistant professor of electrical engineering, determined that mild heat stress at temperatures around 120 degrees F damages the bacteria’s cell walls without rupturing them.
By better understanding the mechanisms of bacterial death at elevated temperatures, the findings can potentially improve food safety strategies and provide more efficient ways to deactivate bacteria using shorter duration of heating at lower temperatures.
“We know how high temperatures kill bacteria,” Ebrahimi said. “But we wanted to find out why Salmonella died at lower temperatures. There are benefits to using lower temperatures, such as saving energy and retaining better nutritional quality, compared to food heated to high temperatures. But more importantly, bacteria can develop resistance to heat shock, so it is important to know how they respond to heat shock.”
The team also studied heating time and heating method, either a slower ramp-up of heat or a sudden pulse of heat, and found that pulsed heat was more effective at killing bacteria.
Ebrahimi’s coauthors on the paper, “Analyzing Thermal Stability of Cell Membrane of Salmonella using Time-Multiplexed Impedance Sensing,” are Lazlo Csonka and Muhammad Alam, Purdue University. The National Science Foundation and a Bilsland Fellowship Award supported the work.
Raw chicken necks can paralyze dogs, sicken owners
Feeding dogs raw chicken meat, particularly chicken necks, has been linked to a rare but potentially fatal type of canine paralysis.
A study led by the University of Melbourne’s U-Vet Werribee Animal Hospital found the consumption of raw chicken meat increased the risk of dogs developing a paralyzing condition called acute polyradiculoneuritis (APN) by more than 70 times.
Dr. Matthias le Chevoir, chief investigator on the project, said the cause of APN in dogs has baffled the veterinary community for a long time.
“It is a rare but very debilitating condition where the dog’s hind legs first become weak and then may progress to affect the front legs, neck, head and face,” he said. “Some dogs may die from the disease if their chest becomes paralyzed.”
Most dogs recover, le Chevoir said, but it can take six months or more.
APN is the canine counterpart of Guillain-Barré syndrome in humans, a condition that also causes muscle weakness and may require ventilation if chest muscles are affected. People who handle raw pet food are at risk of exposure to a number of bacteria, viruses and parasites. Kitchen counters, utensils, pet bowls and hands can become cross contaminated easily.
le Chevoir said Campylobacter is considered a triggering agent in as many as 40 percent of Guillain-Barré patients. The bacteria can be found in a variety of foods, including raw chicken and unpasteurized milk products, and contaminated water.
Martinez and le Chevoir said the fact that raw meat consumption could trigger such dramatic disease is concerning because there appears to be a growing trend for feeding dogs raw meat diets.
Raw cheese outbreak suggests 60-day rule not enough
Ninety percent of 29 people in five Canadian provinces who got sick with the same strain of E.coli O157:H7 between July 12 and Sept. 29 of 2013 reported eating Gouda cheese made with raw milk at a dairy plant in British Columbia.
Five of the people were hospitalized and one died. In 26 cases, people said they ate Gouda cheese from the dairy plant in British Columbia, and all of the 22 patients with sufficient product details available reported eating Gouda cheese made with raw milk.
A research report into the outbreak was publicized Jan. 25, according to the Journal of Food Protection.
The cheese was produced between March and July 2013 and was aged for a minimum of 60 days. The outbreak strain was isolated from the implicated Gouda cheese, including one core sample obtained from an intact cheese wheel 83 days after production. The findings indicate that raw milk was the primary source of the E.coli, which persisted through production and the minimum 60-day aging period. The outbreak was the third caused by the same strain of E.coli traced to Gouda cheese made with raw milk in North America.
The findings provide further evidence that a 60-day ripening period cannot ensure die-off of pathogens that might be present in raw milk Gouda cheese after production and have triggered an evaluation of processing conditions, physicochemical parameters, and options to mitigate the risk of E.coli O157:H7 infection associated with raw milk Gouda cheese produced in Canada, the Journal of Food Protection said.
The 60-day rule was promulgated by the U.S. Food and Drug Administration during the 1940s in response to outbreaks of typhoid fever linked to raw milk cheese. The idea was that allowing the cheese to ferment for 60 days creates an environment too acidic and salty for most bacteria to survive. But some studies have shown that certain strains of E.coli can survive the fermentation process for 100 days or longer.
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