Watercress or yellowcress is a species of aquatic flowering plant in the cabbage family Brassicaceae. Its botanical name is Nasturtium officinale.

Watercress is a rapidly growing, perennial plant native to Europe and Asia. It is one of the oldest known leaf vegetables consumed by humans. Watercress and many of its relatives, such as garden cress, mustard, radish, and wasabi, are noteworthy for their piquant flavors.

The new tips of watercress leaves can be eaten raw or cooked, although caution should be used when collecting these in the wild because of parasites such as giardia. Watercress is 95% water and has low contents of carbohydrates, protein, fat, and dietary fiber. A 100-gram serving of raw watercress provides 11 calories, is particularly rich in vitamin K (238% of the Daily Value, DV), and contains significant amounts of vitamin A, vitamin C, riboflavin, vitamin B6, calcium, and manganese.

Watercress is an aquatic or semi-aquatic perennial herb with bright white flowers that resemble the shape of a cross; hence, an old name (Cruciferae) for the mustard family, to which watercress belongs. Watercress is commonly found in cold, alkaline waters of springs, spring runs, and similar streams throughout the State of Missouri, as well as the majority of the North American continent.

Watercress is also distributed worldwide. It is usually considered an introduced species in North and South America, Australia, South Africa, and New Zealand. In the United States, it is listed by 46 states as noxious and invasive.

Watercress is a member of the mustard family, which includes many well-known leafy and tuberous vegetables such as collared greens, kale, turnips, and radishes, as well as many problematic weeds such as garlic mustard. It is widely cultivated and is the same watercress commonly used as a salad green. It is also used as a garnish for meats and other dishes where a peppery or pungent flavor is desired (Steyermark 1963).

The pungent, spicy, and/or peppery taste of members of the Mustard family is due to a defense system known as the glucosinolate-myrosinase system. When tissue damage, due for example to herbivory, mechanical damage, or pathogen attack, occurs, the mechanism isolating the two compounds (glucosinolate and myrosinase) within the plant tissues breaks down and results in the production of several mustard oils that have a variety bioactive properties (Newman, et al 1992). This arrangement is known as “the myrosinase-glucosinolate bomb.” This “bomb” is thought to be active against herbivores, fungi, viral and bacterial pathogens, nematodes, and even other plants. Thus, the distinctive flavors of many members of the Mustard family are due to the types and amounts of hydrolyzed glucosinolate products released.

With watercress, the glucosinolate-myrosinase system is employed as a defensive mechanism against herbivory by various aquatic herbivores such as caddis flies, amphipods, and snails. However, yellowed leaves of watercress are more readily consumed by these same aquatic herbivores due to the low levels of glucosinolate and myrosinase in the leaf tissues.

Plants collected from the wild should be washed carefully prior to consumption to avoid accidental ingestion of microscopic parasites, such as the protozoan Giardia, that may be present in untreated water (Yatskievych 2006). Ducks, muskrats, and deer eat the leaves of watercress, and the plants serve as shelter for small aquatic life.

As you enjoy fresh produce, follow these safe handling tips to help protect yourself and your family.

Fruits and vegetables are an important part of a healthy diet. Your local markets carry a wide variety of nutritious fresh fruits and vegetables. However, harmful bacteria that may be in the soil or water where produce grows can come in contact with fruits and vegetables and contaminate them. Fresh produce may also become contaminated after it is harvested, such as during storage or preparation.

Eating contaminated produce can lead to foodborne illness, often called “food poisoning.” So as you enjoy fresh produce, follow these safe handling tips to help protect you and your family.

Buy Right

You can help keep produce safe by making wise buying decisions.

• Choose produce that is not bruised or damaged.
• When buying pre-cut, bagged or packaged produce — such as half of a watermelon or bagged salad greens — choose only those items that are refrigerated or surrounded by ice.
• Bag fresh fruits and vegetables separately from raw meat, poultry, and seafood when packing them to take home from the market

Store Properly

Proper storage of fresh produce can affect both quality and safety.

• Store perishable fresh fruits and vegetables (like strawberries, lettuce, herbs, and mushrooms) in a clean refrigerator at a temperature of 40° F or below. Use a refrigerator thermometer to check! If you’re not sure whether an item should be refrigerated to keep its quality, ask your grocer.
• Refrigerate all produce that is purchased pre-cut or packaged .

Separate for Safety

Keep fruits and vegetables that will be eaten raw separate from raw meat, poultry, and seafood — and from kitchen utensils used for those products.

• Wash cutting boards, dishes, utensils, and countertops with soap and hot water between preparing raw meat, poultry, and seafood and preparing produce that will not be cooked.
• If possible, use one cutting board for fresh produce and a separate one for raw meat, poultry, and seafood.
• If you use plastic or other non-porous cutting boards, run them through the dishwasher after use

Prepare Safely

When preparing any fresh produce, begin with clean hands. Wash your hands for at least 20 seconds with soap and warm water before and after preparation.

• Cut away any damaged or bruised areas on fresh fruits and vegetables before preparing and/or eating. Throw away any produce that looks rotten.
• Wash all produce thoroughly under running water before preparing and/or eating, including produce grown at home or bought from a grocery store or farmers’ market. Washing fruits and vegetables with soap, detergent, or commercial produce wash is not recommended. Produce is porous. Soap and household detergents can be absorbed by fruits and vegetables, despite thorough rinsing, and can make you sick. Also, the safety of the residues of commercial produce washes is not known and their effectiveness has not been tested.
• Even if you do not plan to eat the skin, it is still important to wash produce first so dirt and bacteria are not transferred from the surface when peeling or cutting produce.
• Scrub firm produce, such as melons and cucumbers, with a clean produce brush.
• After washing, dry produce with a clean cloth towel or paper towel to further reduce bacteria that may be present on the surface

What About Pre-Washed Produce?

Many pre-cut, bagged, or packaged produce items are pre-washed and ready-to-eat. If so, it will be stated on the packaging, and you can use the produce without further washing.

If you choose to wash produce marked as “pre-washed” or “ready-to-eat,” be sure that it does not come in contact with unclean surfaces or utensils. This will help to avoid cross contamination.

About Foodborne Illness

Know the Symptoms

Consuming dangerous foodborne bacteria will usually cause illness within 1 to 3 days of eating the contaminated food. However, sickness can also occur within 20 minutes or up to 6 weeks later. Although most people will recover from a foodborne illness within a short period of time, some can develop chronic, severe, or even life-threatening health problems.

Foodborne illness can sometimes be confused with other illnesses that have similar symptoms. The symptoms of foodborne illness can include:

• Vomiting, diarrhea, and abdominal pain
• Flu-like symptoms, such as fever, headache, and body ache

Take Action

If you think that you or a family member has a foodborne illness, contact your healthcare provider immediately.