The CDC is currently investigating a large recent E. coli outbreak linked with romaine lettuce.
The agency keeps tabs on the foods that most frequently make us sick — and fresh vegetables are pretty high on the list.
Fortunately, one of the best and easiest ways to avoid getting sick is washing or cooking fresh vegetables before you eat them.
When you think of the foods most likely to get you sick, you may not think of the true worst offenders: fresh fruits and vegetables.
Sure, seafood goes bad easily and meat can frequently be undercooked, but sprouts, spinach, and unpasteurized juices can bowl us over and leave us missing work more often. As part of one of the largest recent outbreaks of a dangerous strain of the bacteria E. coli, the Centers for Disease Control and Prevention is investigating how romaine lettuce sickened at least 53 people across 16 states. So far, the agency believes the source of the illnesses is contaminated leaves from Arizona.
The CDC also keeps tabs on what foods tend to get us sick most frequently. Pulling from more than a decade of outbreak data, CDC scientist John Painter was able to nail down seven common offenders.
Spinach that's unwashed or raw can harbor E. coli and norovirus.
Nearly half of all foodborne illnesses the CDC recorded in its report were caused by produce. Of those illnesses, the vast majority (22%) were linked to leafy vegetables like spinach, making leafy greens the most dangerous commodity of all of the food categories the CDC explored.
Since fruits and veggies are frequently consumed raw, any harmful bacteria introduced to the produce at any time during production could make you sick. Contaminated spinach typically harbors norovirus — the common stomach bug linked with vomiting and diarrhea — and sometimes carries E. coli as well.
Rinsing or washing your produce is a healthy protective step, but this merely decreases the possibility of contamination — it's not a fail-safe, according to the CDC.
Chicken and turkey can be contaminated with listeriosis, which can be deadly.
More deaths documented in the CDC's report were attributed to chicken and turkey than to any other food.
Part of the reason poultry got such a bad rap has to do with three large listeriosis outbreaks traced to turkey deli meat that occurred from 1998 to 2002. Listeriosis is a serious infection caused by listeria bacteria; its symptoms can range from fever and diarrhea to stiff neck, headache, and confusion. Pregnant women, children, and the elderly are the most at risk.
Still, it's important to recognize that, just as it did with unpasteurized juices following several illness outbreaks, the FDA issued new regulatory standards aimed at increasing the safety of deli meat in the years following the listeriosis outbreaks.
Sprouts are frequently contaminated with salmonella.
The moist conditions in which sprouts are grown are also the perfect environment for bacteria — especially salmonella, which can cause diarrhea, fever, and painful stomach cramps. Of particular concern are contaminated seeds.
"A few bacteria present on the seeds can grow to high numbers of pathogens on the sprouts," the CDC wrote on its food-safety page.
Unpasteurized juice is easily tainted by raw fruit, which can harbor E. coli.
From 1995 to 2005, thousands of people across multiple states got sick after drinking tainted unpasteurized juice. The US Food and Drug Administration has since enacted stricter safety regulations for juice producers, but problems have occasionally surfaced.
The issue with unpasteurized juices is that any bacteria or parasites present on the fruit — such as salmonella, E. Coli, or cryptosporidium — can be easily transferred to the finished product.
Because they are bottom feeders, shellfish like oysters can naturally concentrate bacteria.
As bottom feeders, shellfish gradually strain microbes from the sea over many months — building up any marine toxins present in the seawater.
Oysters, for example, can concentrate vibrio bacteria that are naturally present in seawater or other microbes such as norovirus that are present in human sewage dumped into the sea.
Dairy and eggs can be contaminated with salmonella.
Foods that mix the products of many animals, like bulk raw milk or pooled raw eggs, are particularly dangerous because any bacteria that is present in one of the animals can taint the entire batch. While salmonella is the most common culprit, it can be especially hazardous in eggs because certain types of the bacteria can infect a hen's ovary without causing visible changes to the egg.
Ground beef can harbor Clostridium perfringens and E. coli — usually when your burger is undercooked.
As in dairy products, the main problem with ground beef and roast chicken is that they mingle the products of many animals, meaning that the potential for bacterial exposure is high. They can also frequently be undercooked, giving bacteria like E. coli and Clostridium perfringens the chance to replicate.
Read next on Business Insider: Americans are avoiding romaine lettuce after an outbreak — and it reveals one of the most dangerous grocery store habits