One debate about the modern seafood industry focuses on heavy metals and other toxins in the fish we eat, especially large predators such as tuna. The press’s alarmist coverage suggests that we should all stop eating tuna salad sandwiches and toro sushi.

After much hue and cry, the public has been left with a murky understanding of the key facts in this discussion. Environmental toxins such as mercury and polychlorinated biphenyls (PCBs) are mainly relevant to women in their childbearing years, pregnant women, breastfeeding women, babies, and young children. Why? Because these compounds affect fertility, gestation, embryogenesis, and early childhood development.

In these at-risk groups, exposure to high concentrations of mercury or methylmercury (MeHg), both potent neurotoxins, can result in mental retardation, cerebral palsy, and seizures.

But outside of the demographic I mention above, these compounds do not significantly affect our population.

In the end, it’s about running the calculus of risk assessment. Pregnant women should avoid tuna and other fish from the top of the food chain. They should avoid wild fish native to the polluted fresh waters of the US and other countries. They should eat fish that are harvested at a young age, such as salmon. Fish such as tuna and swordfish are taken from the sea after years of exposure to and accumulation of toxins from the fish they eat.

Even following these guidelines (more can be found at the links below), pregnant women should eat these fish in measured doses, eat a wide variety of protein and omega-3 containing foods, and pay close attention to the source of their food.

If you want “cleaner” seafood, farmed fish can be a healthy option if you find a fishery that buys certified toxin-free fish feed, which is very expensive. Farmed fish that eat ground-up and toxin-rich fish-based feed, the majority of farmed fish aquaculture, become toxin sponges. Wild fish might potentially have fewer heavy metals but there is never a 100% guarantee that your particular fish didn’t grow up on the wrong side of the tracks. Fish-by-fish testing is just not available to the retail-level consumer.

If you are not a female of childbearing age, pregnant, or breastfeeding, eat that tuna without much guilt, but don’t feed tuna, swordfish, tilefish, shark, and other large fish to your kids. (See this link for a listing of fish and their mercury content)

Please wait until their little brains have had a good chance to develop properly. While it is not clear when neural development is no longer susceptible to injury due to mercury exposure, it is clear that critical development continues well into the teen years.

Do what you can to help young women, pregnant mommas, and children in your life move away from these food sources.

Resources for Learning:

Got Mercury?

FDA: Mercury Levels in Commercial Fish and Shellfish Updated February 2006

FDA: What You Need to Know About Mercury in Fish and Shellfish - 2004 EPA and FDA Advice For: Women Who Might Become Pregnant, Women Who are Pregnant, Nursing Mothers, Young Children

EPA: Fish Advisories

EPA: Mercury information site

Without getting too political about the effect that the current administration has had on the integrity of certain government agencies, remember to never rely on a single source of information.

Note that organic definitions don’t exist for fish. The USDA has not advocated for organic standards in the past, but policy makers have co-opted the term to ease the way for non-organic food producers to capitalize on this market niche.

A source for Organically fed Farm Fish:

Black Pearl Natural Choice brand (at some Whole Foods Markets)

These days big supermarket chains are selling small numbers of “odd fruits” in the produce section. Maybe the store is trying to compete with the large variety of fruits at upscale grocers or perhaps they think that these fruits are in demand by the “ethnic” shoppers in the area. Maybe they figured out that some people will inevitably become jaded with the MacIntosh and Clemintines they push every day. Some days when I’m shopping, I’m so repulsed by the hot house tomatoes and drab green asparagus bundles soaking in murky water, I check out the odd fruit. Usually, I stare at the display a while, pick up a few fruits, try to imagine what lies inside the rind, and consider buying one to get some spice into the supermarket cart.

That’s how I found myself with a Kiwano (Cucumis tuliferus). This fruit is also known as a Horned Melon, African horned cucumber or melon, jelly melon, hedged gourd, or English tomato. (Kiwano Wikipedia entry)

The rind is a stunning orange-yellow color with spikes. When you cut into it you find the most improbable of evolution’s gifts: little seeds surrounded by livid green gelatinous material. When I was taking the photo I was entranced by the clarity of the gel, the vivid colors, and the spikes on the rind. It looks like it should taste like a green apple Jolly Rancher, but in fact it has a muted, cucumber-like flavor.

Should a kiwano find its way into your cart, the following recipes may give you some ideas for using this unusual fruit.

Recipes:

Even the USDA says this fruit is rather more like a cucumber in taste and perhaps should be considered in cucumber recipes, such as raita.

I found the following recipe for a Kiwano Raita by Chef Norman Van Aken in his book The Great Exotic Fruit Book: A Handbook of Tropical and Subtropical Fruits with Recipes.

Kiwano Melon (Horned Melon) with Chile de Arbol Raita

Ingredients:

1 Kiwano/Horned Melon - cut in half, flesh scooped out and roughly chopped (about 1/2 cup)
1/4 cup red onion finely chopped
1/2 cup plain yogurt
1/4 cup sour cream
1/2 teaspoon black mustard seeds
1/4 teaspoon coriander seeds
1/2 teaspoon cumin seed
1/4 teaspoon black peppercorns
1/8 teaspoon garam masala
1/8 teaspoon chile de arbol
Salt to taste
1/2 tablespoon cilantro leaves, roughly chopped

Directions:
Squeeze the kiwano flesh over a bowl and collect the juice and seeds.

Discard the fibrous pulp. Add the onion, yogurt, and sour cream to the kiwano and mix together.

Combine the mustard, cumin and corander seeds with the peppercorns in a dry skillet. Toast until fragrant and transfer to a spice grinder. coarsely grind and add the yogurt mixture. Add the garam marsala, chile powder, salt, and cilantro, and thoroughly combine. Keep covered in the refrigerator.

Another recipe from Chef Van Aken’s book is -

Secret of Paradise Ice Cream Dessert

You’ll need one large kiwano, one small tub of banana yogurt, honey to taste, and vanilla ice cream. Cut fruit in half and remove pulp. Mix honey, yogurt, and pulp. Pour into kiwano half-shell. Add ice cream, whipped cream, and a cherry.

Books and Resources of Interest

The Great Exotic Fruit Book: A Handbook of Tropical and Subtropical Fruits with Recipes.

Purdue University puts out a rather long kiwano fact sheet that will help you in your post-graduate Kiwano studies.

Other Kiwano recipes

Flounder with Kiwano Salsa (halfway down the page) from the Charleston Seafood Company.

A huge list of Kiwano based drinks at “Drinks to Infinity and Beyond”.