E. coli

Lettuce Learn a Bit About E. Coli

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By Diane Wright Hirsch, MPH

Senior Extension Educator/Food Safety

 

romaine lettuce
Photo: Wikimedia Commons

Recent news reports regarding the romaine lettuce outbreak have, yet again, raised concern about pathogens in our food supply. In particular, leafy greens continue to show up as a source for outbreaks. Two outbreaks since late fall have implicated romaine and/or leafy greens. In both outbreaks, E. coli O157:H7 was the culprit.

What exactly is E. coli?

Escherichia colior E. coliis a group of bacteria, some of which are harmless, and some of which are pathogenic, or disease causing. These bacteria are ubiquitous in the environment: they can survive in water, soil, on plants, and in the intestinal tracts of people and animals. Some types of E. colicause diarrhea, some cause urinary tract infections, and other may cause pneumonia or other diseases.

If you have a well, you are likely familiar with the term “generic E. coli.”  Generic E. coli(sometimes referred to as Biotype I), is found in the intestinal tracts of animals. Therefore, the public health and regulatory community use the presence of generic E. coliis an indicator that some type of fecal contamination (poop) is present. A test for generic E. colican determine if well water is drinkable, if food processing environments are clean, if meat is potentially contaminated with fecal matter or if irrigation water is safe to use on crops.

Generic E. coli, because it is found in fecal matter, may also indicate the potential for the presence of other pathogens that can be found in feces: bacteria such as Salmonellaand pathogenic types of E. coli; viruses such as hepatitis A or norovirus; and parasitic protozoa including Cryptosporidium parvum. All of these microorganisms have been associated with foodborne disease outbreaks.

While there are a number of pathogenic strains, it is Shiga toxin-producing E. coli(STEC) or enterohemorrhagic E. coli(EHEC) that is identified most often as a cause of foodborne illness. O157:H7 is one of several STEC strains. Hamburger, spinach, lettuce, sprouts, unpasteurized or “raw” milk and cheeses, unpasteurized fruit juice including cider, and  flour have all been identified as food sources in O157:H7 outbreaks.

This can be an awful disease. This type of E. coliproduces a Shiga toxin, which can be associated with more severe disease, including bloody diarrhea and hemolytic uremic syndrome (HUS), a type of kidney failure. The experience of an STEC infection can be different for each person. Contributing factors might include the age of the patient (very young or older people may have more severe infections due to compromised or undeveloped immune systems) and the general health of the person (again, if the immune system is already compromised, the disease may be more severe). However, a healthy adult can also experience more severe disease. Often, the symptoms include severe stomach cramps, diarrhea (often bloody), and vomiting. Again, the CDC states, “If there is fever, it usually is not very high (less than 101˚F/less than 38.5˚C). Most people get better within 5–7 days. Some infections are very mild, but others are severe or even life-threatening.”

Life threatening complications can occur when the Shiga toxin latches onto specific organs, such as the kidney. HUS can result in short term kidney failure or may result in long term disability, or even death.

How does E. coli get into our food?

We have been aware of the risk of E. coliin animal products for years. According to the Centers for Disease Control, “STEC live in the guts of ruminant animals, including cattle, goats, sheep, deer, and elk. The major source for human illnesses is cattle. STEC that cause human illness generally do not make animals sick. Other kinds of animals, including pigs and birds, sometimes pick up STEC from the environment and may spread it.”

It was likely the Jack in the Box hamburger related outbreak in 1993 that increased the awareness of both the public and the public health community of the relationship. After that outbreak, Rhode Island passed a law that does not allow restaurants to serve undercooked hamburgers to kids under 12 – a population that is at risk for the worst consequences of an E. coliinfection. At the same time, the recommended safe end-cooking temperature of hamburger was increased to 160 degrees F and sweeping regulation was passed that required meat and poultry processors, to develop food safety plans and be part of a food safety regulation program that included testing for generic E. coli,as well as pathogenic strains of the bacteria.

That makes sense to consumers. After all, if these pathogens are found in the intestinal tracts of animals and in fecal matter, then animal foods are most likely at risk for contamination.

So, how are fruits and vegetables contaminated with E. coli? As stated earlier, E. colican live in ruminants, including deer. Other wildlife may carry the bacteria after picking it up from the environment—the soil, dead animals, or contaminated water. The great outdoors is also the great toilet for these animals. Their feces end up in the soil and water or on the feed of birds or insects. Fruits and vegetables are grown in this soil. There is some risk of contamination as a result. Birds poop on tomatoes, apples fall on deer poop, etc.

Newer regulation target produce growers in an effort to reduce the risk for foodborne illness from fresh fruits and veggies. The Food Safety Modernization Act Produce Safety Rule includes requirements to test irrigation water, keep records of sanitation practices in the packing house, and employee training concerning personal hygiene and safe handling of produce.

Leafy greens continue to be associated with more outbreaks than other types of vegetables, with the exception of fresh sprouts. First, we eat them raw. There is no kill step to destroy pathogens. Second, they are leafy and grow close to the soil. If contaminated, those leaves can harbor and protect the bacteria. If lettuces are cut and then washed, the contamination can spread to greens that have not been contaminated, making the problem bigger. Once cut or chopped, the greens have even more open surface area that may allow the bacteria to internalize.

Like meat and poultry, any food product that is grown in the field will never be 100% risk free. The industry is hard at work doing what they can to reduce your risk.

So what should a consumer do?

First, do not stop eating greens, tomatoes, or other fresh fruits and vegetables. The benefits of a diet high in fresh produce far outweigh the risk of contracting a foodborne disease from them. Learn how to choose, store, prepare and handle them safely.

Purchase your produce from a farmer that has instituted good agricultural practices and good produce handling practices. If you buy from a local farmer at the farm or at a farmers’ market, ask the farmer if they have attended a food safety course or if they have a food safety program on their farm.

When buying fresh produce, avoid those that are bruised or cut if you are going to eat them raw.  Openings in the skin or bruises may increase the ability of bacteria or other microorganisms to reach the flesh of the fruit or vegetable. Refrigerate produce that should be refrigerated (leafy greens, scallions, broccoli, cucumbers) to minimize growth of microorganisms. In addition, refrigerate all cut produce.

Other food safety tips:

  • Wash all produce prior to eating.
  • Use clean knives, cutting boards, hands and other utensils when preparing raw lettuce for a salad or cutting a melon for breakfast.
  • Don’t cross contaminate ready-to-eat fresh produce with raw meat or poultry. I always prepare the salad first, then the meat for my meal.
  • Store raw, ready-to-eat produce to protect it from raw meat, poultry or fish.
  • Place the meat on a plate if it must be stored above the veggies. (I can never understand why produce drawers are under all other shelves in the fridge, making it a bit easier for meat juices to drip down onto the fresh produce.)

Some folks may want to consider purchasing heads of lettuce rather than chopped greens, though even whole heads of romaine were implicated in the most recent outbreak. If you do purchase pre-cut greens, make sure they are of good quality without a lot of browning or slimy leaves in the bag. If they are washed it is best not to rewash as you risk contamination during the process. However, if there are beginning signs of wilting or mushy leaves, I would wash, dry and store the remaining greens in the refrigerator, wrapped in a clean paper towel.

Continue to enjoy salads, fresh fruit and other veggies on a daily basis. It is an important part of a healthy diet. Just be sure to pay attention good safe food handling practices as you prepare to enjoy your meal.

For more information about food safety, visit our website at www.foodsafety.uconn.edu, check out some of the links in the article, or contact the Home and Garden Education Center at ladybug@uconn.edu or 1-877-486-6271.

Food Safety and Foodborne Illness: There Will Always Be Surprises

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By:           Diane Wright Hirsch, MPH

Senior Extension Educator/Food Safety

dole spinach
Photo: FDA

I took on food safety as a focus of my Extension programming in the early 1990’s: little did I know that for the next 20-plus years my food safety educator life would be full of surprises. Early on, the issues were what a consumer would expect them to be—salmonella and eggs, salmonella and chicken, seafood as a source of a variety of foodborne illnesses. After all, these are all animal based products, high in protein, low in acid, the perfect breeding ground for the bacteria that cause much foodborne illness.

But at the same time, Listeria monocytogenes was an emerging pathogen that would soon become ubiquitous in the food processing industry. We learned that E. coli COULD survive an acid environment such as apple cider. And then came an onslaught of outbreaks related to fresh produce, which heretofore was not considered what were called, potentially hazardous foods or PHF, in the FDA Model Food code.

Like all science, the science of food safety is ever evolving. And so too are the unfortunate targets of the microorganisms that cause foodborne illness.

Some of the surprises over the years have resulted in additional regulation. The Jack in the Box E. coli outbreak (as well as others), was one driver of the 1996 USDA “Mega-reg” that required all meat and poultry processing plants to develop food safety systems based on HACCP or Hazard Analysis Critical Control Point programs. These programs lay the onus on the industry to identify the food safety hazards that could potentially affect their products and/or processes and to adopt controls to prevent the hazards or at least to minimize the risk of a foodborne illness from these hazards once their product gets into commerce and ultimately the consumer.

Similarly, it was a series of outbreaks affecting apple cider, apple juice (Odwalla, 1994) and other fresh juices that resulted in the FDA Fresh Juice HACCP regulation in 2001.

The FDA Food Code has also adapted over time as new foods or food processes have added risk to foods that weren’t identified as hazards in previous editions. Currently, seed sprouts, sliced melons, sliced tomatoes, and cut lettuces are all considered time-temperature for control foods (formerly PHF). Each of these were added following outbreaks that affected them. All are low acid foods that support the growth of microorganisms.

So, yes, outbreaks can surprise us. Consider some of the food products that have shown up in the news recently.

  • Deer antler tea and botulism—affected two in California. (Maybe the biggest surprise here is that someone actually drinks deer antler tea?)
  • coli in flour, including a rare form, O121 in a Canadian flour source
  • Botulism in carrot juice (was mishandled by consumers)
  • A variety of outbreaks tied to pet food
  • Frozen vegetables: this Listeria outbreak and subsequent recalls affected as many as 350 consumer products sold under 42 brand names.
  • Chicken pot pies (a result of unclear labeling, consumer handling)
  • Not an outbreak, but still a hazard—golf balls in hash browns?
  • Pepper and other spices in ready to eat products (coatings on cheese or salami), in spice mixes and simply on their own in a bottle.

Sometimes, it is not the outbreak that surprises us, but the extent of the consequences. Raw milk is an example of this. Outbreaks tied to raw milk are not unusual, but a soon to be released report from the Centers for Disease Control indicates that unpasteurized milk and cheese products caused 96% of illnesses attributed to dairy products. This is an important statistic.

In several recent outbreaks, including the Peanut Corporation of America and the Jensen Brothers Farm Listeria outbreak in cantaloupe, the owners and some employees of the companies were arrested and given hefty fines, probation, and in some cases, prison sentences.

Lessons learned, changes made

There will always be surprises. In my food safety courses for industry personnel, I use some of these examples as lessons for those who insist that an outbreak or recall will never happen to them. The Food Safety Modernization Act (FSMA) was itself the end result of many surprises. The foods regulated by the FDA are not under as much scrutiny as those regulated by the USDA. Inspections are less frequent. Businesses really do need to take responsibility for the safety of their food as the government agency that oversees them simply does not have the resources to do so. So after a series of outbreaks tied to FDA regulated foods (peanut butter, cheese, spinach, melon, sprouts, pet foods and others) that were not previously required to have a food safety program in place, FSMA was adopted. Included in the regulation were rules addressing fresh produce, processed foods (except those currently under HACCP regulations such as juice and seafood), pet foods and imports. A thriving third party audit industry has also developed as customers of food processors seek greater assurances that the products they are buying are produced under a food safety program.

What is a consumer to do?

Consumers should simply remain vigilant. Keep up on recalls or outbreaks that affect the foods you eat. If you like to get emails, you can sign up for notifications of recalls on both the FDA site (www.fda.gov) and the USDA Food Safety Inspection Service site (www.fsis.usda.gov). Consider using shopper loyalty cards when your supermarket makes them available. They are often used to contact consumers who may have purchased a product associated with an outbreak or recall.

A more reasonable approach may simply to be to learn about how you get sick from food. Learn about the importance of temperature controls, including cooking times and temperatures, keeping cold foods cold, and cooling foods properly. Learn about cross contamination of ready to eat foods with contaminated foods (raw meat), dirty hands or dirty countertops. Don’t eat raw foods that should be cooked for safety (raw, undercooked meat or eggs or doughs for example) and handle ready to eat foods like lettuce and cantaloupe carefully. Follow cooking instructions on the processed foods you buy—especially if you are using a microwave oven. You can learn about how to handle food safely at the UConn Food Safety website (www.foodsafety.uconn.edu) or by visiting www.foodsafety.gov .

In other words, take responsibility for the foods that you handle. While that may not ensure that you will be forever free from foodborne illness, at least you will be less likely to be the cause of that illness.

Poop Happens

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By Diane Wright Hirsch, UConn Extension Educator

 

hand washing
Photo: Clemson Extension

Farm animals poop. Why should that matter to me…a frequent farm visitor?

We all poop. Dogs poop, cats poop, cows and even goats poop. It is a natural process that rids our bodies of indigestible food and waste products. Unfortunately, it is also a way to carry pathogens (the kind of germs that make us sick) out of our intestines.

E. coli O157:H7 is one of those pathogens. The O157:H7 is only one strain or serotype of the Escherichia coli bacteria family. In fact most E. coli are not harmful to humans and are found living comfortably in our intestinal tract.

However, E. coli O157:H7 can cause an intestinal disease in humans that can have disastrous consequences. Symptoms of this disease include watery or bloody diarrhea, fever, abdominal cramps, nausea, and vomiting. The illness can be mild to severe. Many food-borne illnesses share these symptoms, so the unaware may simply ignore them or write them off as a 24-hour bug. But, in the very young, the elderly and those with compromised immune systems, the result of an infection with O157:H7 can lead to severe problems—including kidney failure—and even death.

So why should this matter to a farm visitor who may wander up to a goat or sheep or cow, hug them, pet them, even kiss them? The problem is that this human pathogen can be present in the intestinal tract of these animals. They may shed the bacteria in their poop, but still appear healthy and clean. The bacteria can easily contaminate the animals’ skin, fur, feathers, and the areas where they live and roam. If the goats or cows are producing milk that is consumed unpasteurized or their milk is being made into an unpasteurized cheese, then these food products could also carry the pathogen.

There is something you can do to protect yourself and your family. When visiting a farm, a petting zoo, or even a county fair, always look for a hand washing facility after sharing some face time with the animals. While a hand sanitizer may provide a minimal amount of protection, pathogens like these require the full hand wash treatment. Rinse hands under running warm water, soap and scrub hands for at least 30 seconds, to create a good amount of lather, including between fingers, under finger nails and up past the wrists, then rinse with warm water. If the farm does not have a hand wash station or public bathroom facility, maybe you should visit a different farm.

For more information, visit the Centers for Disease Control at: http://www.cdc.gov/healthypets/diseases/ecoli.html

Safe Food Handling from Farm to Table

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Written by Patsy Evans for Naturally@UConn and originally posted on October 14, 2014

Screen Shot 2014-10-20 at 3.38.24 PMHearing the word ‘outbreak’ makes many people anxious. E. coliO157:H7, spinach, 2006. Salmonella, peanut butter, 2009. Listeria, cantaloupe, 2011. Diane Hirsch, UConn Extension educator for food safety, easily lists previous food-borne pathogen outbreaks. But, fear does not paralyze her.

Instead, she works in classrooms and on farms to make sure that locally produced food, which ends up on tables in New England, is as safe as possible. Her mission: “safe food handling from farm to table.” Her audience includes growers who put produce in boxes on their farms, commercial artisanal cheese makers and home cooks who preserve food in their kitchens.

With the help of over $82,000 in USDA grants, Hirsch trains farmers to follow Good Agricultural Practices (GAP) and processors to develop food safety plans. She labors to see farm products that are, according to USDA, “produced, packed, handled, and stored in the safest manner possible to minimize risks of microbial food safety hazards.”

Because of past outbreaks, grocery store chains that buy food from farmers are putting more pressure on them to follow food safety guidelines and submit to voluntary audits. Hirsch estimates that 12 to 14 Connecticut farmers are currently GAP audited. She wants her training programs and farm visits to increase that number by “helping people do what they need to do” in reducing the possibility of contamination and preparing for audits.

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