Most people generally assume that the food they buy is safe to eat. Although this is usually true, even developed countries like the United States can experience widespread food contamination outbreaks. In October 2013, Taylor Farms, the world’s largest producer of fruits and vegetables, announced a massive 25-state recall of broccoli salad kits. In the same month, Oregon-based Reser’s Fine Foods issued a recall of its own, asking supermarkets to return nearly 23,000 pounds of chicken, beef and ham. The microscopic culprit responsible for both cases was listeria, a type of bacteria that can live on a variety of foods.
The Spread and Impact of Listeria
Listeria is a genus of bacteria that includes ten distinct species. Despite this fact, just one of these species – listeria monocytogenes (abbreviated as l. monocytogenes) – accounts for nearly all listeria infections in humans. While the natural habitat of these potentially dangerous bacteria is soil and water, l. monocytogenes can spread into the human food supply through a number of different avenues.
A wind range of popular foods can become hosts to listeria bacteria. Vegetables can be contaminated if listeria slips into the fertilizer used to help them grow. Alternatively, listeria can also work its way into vegetable crops via the surrounding soil. This type of bacteria can also be ingested by livestock, and subsequently wind up in common meat and dairy offerings sold at the grocery store. Additionally, Listeria can fester inside food processing plants, where it can enter such fare as processed cheese and cold cuts.
Though it can strike a wide range of foods, listeria infections are fortunately not a common occurrence. Each year, only about 2500 Americans contract listeriosis, the disease caused by l. monocytogenes. As uncommon as listeriosis may be, it can still be quite dangerous; about 500 people die annually from listeriosis, giving this disease a mortality rate in the neighborhood of 20%.
The groups must vulnerable to listeria infection are infants and pregnant women In fact, an expecting mother is 20 times more likely to be infected by listeria than the average healthy adult. Likewise, people with immune systems compromised by other diseases face an elevated risk from listeria. The list of ailments known to increase a patient’s susceptibility to listeriosis reads as follows:
- HIV/Aids, along with other diseases that attack the immune system
- Liver Disease
- Alcohol Addiction
- The later stages of renal disease (a condition that cripples the kidneys)
Given its high mortality rate, you might assume that a listeria infection has a devastating impact on the human body. In reality, this is often not the case; patients who are not among the more at-risk groups to listeria seldom fall seriously ill due to a listeria infection. Because of this, otherwise healthy adults and children typically exhibit relatively mild symptoms, such as fever, muscle aches and possibly diarrhea and vomiting. These patients usually make a full recovery in a matter of weeks, and do not require any specific medical treatment.
The story can be quiet different for pregnant women. In addition to the symptoms described in the preceding paragraph, the bacteria may spread to the mother-to-be’s nervous system. In turn, this could trigger stiffness in the neck, headaches, bouts of confusion and possibly even convulsions. The woman’s balance could also be adversely affected.
Conversely, the mother may only encounter mild symptoms that mimic a flu infection. However, listeria bacteria can have a far more serious impact on the woman’s unborn child. If the mother is not appropriately treated, the fetus could develop an infection of its own soon after birth. In some cases, the outcome can be even more tragic, with the listeria leading to miscarriage, premature delivery or even stillbirth. Antibiotic drugs are frequently used for treating listeriosis in pregnant women and infants. Newborns may require a certain combinations of antibiotics.
Keeping Listeria Out of Your Food
If the recent recalls have you concerned about the presence of listeria in your food, following some practical rules can help ensure the quality of your meals.
Pay Attention When Shopping – Meat, poultry and fish should not be placed in the same bag with non-meat products at the checkout aisle. Doing so could give listeria the chance to cross-contaminate other foods.
Handle Food Correctly – It’s not hard for bacteria to hitch a ride onto your hands during the day. If not removed with soap and water, these bacteria can wind up on your food and quickly get inside your stomach. Harmful bacteria can also be found lurking on grocery store produce, so wash both fruits and vegetables under running water as a precaution. When chopping up food, try using two separate cutting boards – one for fruits and veggies, and another for meat, seafood and poultry.
Keep Groceries in a Proper Environment – Leaving perishable foods out on the counter or in the back of the car can provide a breeding ground for bacteria. This is especially true of fish, meat, poultry, eggs and various ready-to-eat items. A good rule of thumb is to properly store such foods within two hours after leaving the supermarket. When storing food, keep a close eye on the temperatures of your refrigerator and freezer. Your refrigerator should not exceed 40°F (or 4 degrees Celsius), whereas the limit for your freezer should be 0°F (-18 °C).
Listeria can be a very tough nut to crack, since it can survive the cold temperatures found in refrigerators. This means that listeria can spread inside your fridge, such as when meat juices spill and leak onto other items. Make sure to clean up any such spills as soon as you see them.
You Are What You Eat – If you have doubts as to a food’s safety, you’re better off throwing it away than taking your chances. Simply reheating food carrying listeria isn’t enough to sterilize your meal.
Since they have a greater propensity to develop listeriosis, pregnant women are encouraged to follow their own specific set of preventative measures. The Centers for Disease Control and Prevention (CDC) offers the following guidelines to pregnant women, which detail which foods should be avoided.
- Hot dogs, luncheon meats, or deli meats. Pregnant women can only eat these items if they are reheated to the point of being steaming hot.
- Soft cheeses, such as feta, Camembert and Brie, along with Mexican cheeses like queso fresco, queso blanco and Panela. Pregnant women should also not eat blue-veined cheeses. (The only time soft, Mexican and blue-veined cheeses are safe to eat is when they feature labels stating that they have been made with pasteurized milk).
- Refrigerated pâté or meat spreads.
- Refrigerated smoked seafood, which often features labels like “smoked,” “kippered,” “jerky,” “nova-style,” and “lox.” The only scenario in which such foods are safe is when they are part of a cooked dish, such as casserole.
- Unpasteurized milk, or products that contain unpasteurized milk as an ingredient.