MYTH OR FACT: FOODBORNE ILLNESS

MYTH OR FACT: FOODBORNE ILLNESS 

From the FMS Global News Desk of Jeanne Hambleton

Released: 9/24/2013 11:00 AM EDT
Source Newsroom: Institute of Food Technologists (IFT)

 

Newswise — IFT spokesperson Christine Bruhn, Director of the Center for Consumer Research at University of California-Davis, dispels some common myths about foodborne illness and gives tips on how to prevent it.

#1: The taste of food will tell you if it’s bad.
Myth: Not true at all! Foods that are contaminated with lysteria, E. coli, salmonella, etc., can all taste great.

#2: Once a food is cooked, it is safe to leave out for hours.
Myth: If you have cooked something and have leftovers, you have got two hours to get those leftovers in the refrigerator and get them cold in order to prevent the spread of bacteria. Thin-walled metal, glass or plastic containers that are shallow (no more than 2 inches deep) are ideal for storage. Bags, foil and plastic wrap also work well, especially if you have a piece of food that is large or oddly shaped. For more information on leftovers.

#3: You can tell by your eyes if something is adequately cooked.
Myth: Not so. You need to use a food thermometer. Recent research from Kansas State showed that a quarter of the burgers turned brown before they reached the recommended 160 degrees Fahrenheit.

#4: Foodborne illness can happen within a few hours.
Fact: The most common ones, such as staphylococcus or clostridium happen within a few minutes to a few hours, and you can feel really awful, but last for only about a day or so. However if you have one of the more serious ones such as salmonella or certain strains of E. coli, it takes longer for illness to appear. Sometimes several days can go by. Illness from listeria can take two months before symptoms appear, and you get really sick. Fortunately, most foodborne illnesses are not fatal.

#5: Preventing Foodborne Illness is Easy:
Fact: The most common way to avoid foodborne illness is by washing your hands. In a study where people were videotaped in their own kitchen, only half of them washed their hands before starting to prepare food.

Keep your kitchen spotlessly clean by washing the cooking area, the preparation area, knives, cutting boards, and utensils to avoid spreading bacteria throughout the kitchen. In addition, the refrigerator should be cleaned because bacteria can grow, albeit slowly, in many environments including inside your refrigerator.

“A dropped item is immediately contaminated and cannot really be sanitized,” said Jorge Parada, MD, MPH, FACP, FIDSA, medical director of the Infection Prevention and Control Program at Loyola University Health System. “When it comes to folklore, the ‘five-second rule’ should be replaced with ‘When in doubt, throw it out.’ ”

SALMONELLA’S ACHILLES’ HEEL: RELIANCE ON SINGLE FOOD SOURCE TO STAY POTENT

Study suggests genes needed for nutrient could bee attractive drug target to fight infection. 

From the News Desk of Jeanne Hambleton

Released: 24-Jun-2014 1:00 PM EDT  Source Newsroom: Ohio State University

 

Newswise — COLUMBUS, Ohio – Scientists have identified a potential Achilles’ heel for Salmonella – the bacteria’s reliance on a single food source to remain fit in the inflamed intestine.

When these wily bugs cannot access this nutrient, they become 1,000 times less effective at sustaining disease than when they are fully nourished.

The research suggests that blocking activation of one of five genes that transport the nutrient to Salmonella cells could be a new strategy to fight infection.

“For some reason, Salmonella really wants this nutrient, and if it cannot get this one, it is in really bad shape,” said Brian Ahmer, associate professor of microbial infection and immunity at The Ohio State University and lead author of the study. “If you could block Salmonella from getting that nutrient, you could really stop Salmonella.”

The research is published in the journal PLOS Pathogens.

Generally, most of the 42,000 Americans who report Salmonella infection annually ride out the gastroenteritis symptoms of diarrhea, fever, stomach cramps and vomiting for four to seven days, according to the Centers for Disease Control and Prevention. Antibiotics are not a recommended treatment for most infections because they kill good gut bacteria along with Salmonella.

The nutrient needed by Salmonella is composed of a sugar and amino acid stuck together, and is called fructose-asparagine. Its identification alone is also unusual: “It has never been discovered to be a nutrient for any organism,” Ahmer said.

Ahmer and colleagues found this important food source by first identifying the genes that Salmonella requires to stay alive during the active phase of gastroenteritis, when the inflamed gut produces symptoms of infection.

Using a genetic screening technique, the researchers found a cluster of five genes that had to be expressed to keep Salmonella from losing its fitness during gastroenteritis. They then determined that those vital genes work together to transport a nutrient into the bacterial cell and chop up the nutrient so it can be used as food.

The study refers to the pathogen’s fitness because it’s an all-encompassing word for Salmonella survival, growth and ability to inflict damage.

Identifying the nutrient that the genes acted upon was a bit tricky and involved some guessing, Ahmer said. The team realized that the Salmonella genes they found resembled genes in other bacteria with a similar function – transporting the nutrient fructose-lysine into E. coli. But seeing a difference between the genes, the researchers landed, with some luck, on fructose-asparagine.

The researchers ran numerous experiments in cell cultures and mice to observe what happened to Salmonella in the inflamed gut when these genes were mutated. Under differing conditions, Salmonella’s fitness dropped between 100- and 10,000-fold if it could not access fructose-asparagine, even if all of its other food sources were available.

“That was one of the big surprises: that there is only one nutrient source that is so important to Salmonella. For most bacteria, if we get rid of one nutrient acquisition system, they continue to grow on other nutrients,” Ahmer said. “In the gut, Salmonella can obtain hundreds of different nutrients. But without fructose-asparagine, it is really unfit.”

Because of that sole source for survival, the genes needed for acquisition of this nutrient could be effective drug targets.

“Nobody has ever looked at nutrient transporters as drug targets because it is assumed that there will be hundreds more transporters, so it is a pointless pursuit,” Ahmer said.

This kind of drug also holds promise because it would affect only Salmonella and leave the trillions of other microbes in the gut unaffected.

Ahmer and colleagues are continuing this work to address remaining questions, including the window of time in which access to the nutrient is most important for Salmonella’s survival as well as identifying human foods that contain high concentrations of fructose-asparagine.

This work was supported by grants from the National Institute of Allergy and Infectious Diseases and the National Institute of General Medical Sciences.

Co-authors include Mohamed Ali, Christopher Stahl, Jessica Dyszel, Jenee Smith and Yakhya Dieye of microbiology; Juan Gonzalez, Anice Sabag-Daigle and Brandi Steidley of microbial infection and immunity; Judith Dubena, Prosper Boyaka and Steven Krakowka of veterinary biosciences; Razvan Arsenescu of internal medicine; and Edward Behrman of chemistry and biochemistry, all at Ohio State; Peter White and the late David Newsom of the Research Institute at Nationwide Children’s Hospital; and Tony Romeo of the University of Florida.

 

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