Insects (the original white meat)

May 23, 2008 at 11:09 am

You bite into a piece of candy and find a cricket leg. Eewwww. Or notice that raisin in a bowl of cereal has legs and wings. Bam, down the disposal it goes. Such filth in foods is supposedly illegal, but the Food and Drug Administration’s actual tolerance is far from zero. FDA rules allow up to 60 insect fragments on average in a composite of six 100-gram chocolate samples. For peanut butter, it’s OK to have up to 30 insect pieces per 100 grams. Grossed out yet?

TASTY MORSELS Asian market offering insect larvae and other delicacies. VB Meyer-Rochow/ Jacobs Univ.

ALL YOU CAN EAT Buffet offering in Thailand of stir-fried grubs with chilis. PB Durst/UNFAO

In the industrialized world, most people find the idea of eating insects repugnant. Processed foods containing bug bits tend to reflect poor sanitation. Because bugs can host disease-causing germs, insects tainting the food supply pose a health risk

Yet in many parts of the world, diners actually desire insects. Youngsters in central Africa may down ants or grubs while at play. Urbane snack-seeking consumers throng street vendors throughout Southeast Asia to buy fried crickets. Even car-driving Aborigines in Australia’s outback may motor a couple of hours to find, and then picnic on, a cache of honey ants.

Residents of at least 113 nations eat bugs, says Julieta Ramos-Elorduy of the National Autonomous University of Mexico in Mexico City. This practice, known as entomophagy (en-toh-MOFF-uh-jee), makes sense, she says, because insects tend to be quite nutritious. Indeed, many scientists around the world have put insect eating on their research menus. It was also the focus of a February United Nations conference in Thailand, where researchers discussed insect-eating trends and evaluated the nutritional value of bugs and the environmental aspects of entomophagy.

“We’re not going to convince Europeans and Americans to go out in big numbers and start eating insects,” concedes conference organizer Patrick B. Durst. However, fostering respect for entomophagy could do a lot to maintain health and environmental quality outside the industrial West, argues Durst, a senior forestry officer with the U.N. Food and Agriculture Organization’s regional office in Bangkok.

He holds out hope that Westerners may become more accepting of insect protein—especially if they “don’t have to look the bug in the eye as they’re eating it.” Dutch researchers are working on just such a development—biotechnology to produce insect cells, minus the insects, as an inexpensive source of edible protein.

Almost 125 years ago, Vincent Holt published a 99-page tract in Britain titled Why Not Eat Insects? It failed to catalyze a bug-eating revolution. David Gracer, a community college writing teacher by day, has now taken up Holt’s cause outside the classroom. Not only does Gracer travel the lecture circuit, he also holds cooking demonstrations so that Americans can sample insect-based snacks and bug-laced entrees. His company, Sunrise Land Shrimp, in Providence, R.I., supplies frozen and dried insects to chefs and other individuals.

Grilled cicadas are more likely to elicit a “yikes” than a “yum” from most Europeans and North Americans. “But why?” asks Gracer. “Most of these people are happy to eat crab, lobster and shrimp—the ocean equivalent of insects.”

Shrimp, other crustaceans and insects are all arthropods—members of the largest phylum in the animal kingdom. When people appear squeamish about tasting a grasshopper or beetle larva, Gracer points out that despite lobster’s prized status, crustaceans tend to “eat trash and dead things” whereas most insects dine at nature’s salad bars.

A matter of taste

Edible insects fill a rather small niche market in the United States, Gracer concedes. Throughout most of the developing world, by contrast, dining on bugs is not only a time-honored tradition but often a treat.

That’s something biologist Gene R. DeFoliart has explored for 33 years, first as chair of the University of Wisconsin-Madison’s entomology department, and more recently as host of the food-insects.com website. Since retiring 17 years ago, he has been compiling data on entomophagy. His site offers a book-in-progress with 28 chapters.

Westerners tend to consider insect eating a last resort; you choke down bugs only if there’s no chicken or beef available. Throughout the tropics and subtropics, however, certain insects, such as adult termites or various grubs, can be preferred to the flesh of birds, fish or traditional meat animals, DeFoliart has found.

Entomophagy thrives in Mexico, where Ramos-Elorduy has cataloged some 1,700 species that are eaten. Although grasshoppers are especially popular and inexpensive, diners in Mexico’s bigger cities will shell out $25 U.S. for a plate of maguey worms, larvae of the giant butterfly Aegiale hesperiaris, DeFoliart notes.

This reflects the fact that insects “now have a clear place in industrialized societies since chefs of different nationalities cook them in very sophisticated ways,” Ramos-Elorduy contends. In Mexico, she finds that “the great demand is for five-star restaurants.” Small bistros tend to serve insects seasonally, she says, but “the five-stars do it daily.”

Throughout much of Africa, mopane (moh-PAH-nee) worms—caterpillars of Gonimbrasia belina, a moth that feeds on mopane trees—are a spectacularly popular snack. In fact, people have been eating so many that biologists have begun worrying that these bugs might be headed for extinction. Sales of dried mopane worms in South Africa alone can exceed 1,600 metric tons per year, DeFoliart found.

Because the caterpillar metamorphoses in soil, it used to be “taboo to dig the worm that has gone underground,” notes O. Ricky Madibela, formerly at the Botswana College of Agriculture in Gaborone. Today, however, people excavate dirt around mopane trees for this “seed of the next generation” of caterpillars. And that, he argues, is unsustainable.

In many regions, however, once-popular entomophagy is waning. Evidence for this shift emerged in Ecuador while entomologist Andrew B.T. Smith of the Canadian Museum of Nature in Ottawa and Ecuadorian Aura Paucar-Cabrera of the University of Nebraska-Lincoln, were studying the scarab Platycoelia lutescens. For the project, Paucar-Cabrera interviewed 48 residents in and around Quito about this white beetle’s role in the local diet.

Everyone recognized the Andean insect—called catso blanco—as a culinary flavoring. And the 24 people from the rural and urban working classes all said they ate the beetles at least once a year. Some took their entire families out to nearby meadows in late October or early November to catch adult beetles emerging after metamorphosis in the soil. But among the 24 wealthier families and professional adults surveyed, only one admitted trying the beetles. The rest professed no interest in ever doing so.

Similarly, teens and young adults in Kenya’s Luo tribe tend to view eating bugs as so last-century, notes food scientist Francis O. Orech of the University of Maryland Eastern Shore in Princess Anne. A Luo himself, Orech recalls eating ants and termites as a child. Now, to interview some 30 Luo about entomophagy, he and a largely Danish group of researchers had to consult people over age 45 to find individuals who still knew where to reliably find bugs, how to catch them and how to prepare them for eating.

Better than beef?

The five species most widely eaten by surveyed Luo were ants, termites and a species of mondo cricket. All were good sources of minerals, but the crickets were the richest and an ant species the poorest, Orech’s group reported in the International Journal of Food Sciences and Nutrition in 2006.

In fact, the team found that crickets contained more than 1,550 milligrams of iron, 25 milligrams of zinc and 340 milligrams of calcium per 100 grams of dry tissue. Traditional cuisines in developing countries often fall short of the global guidelines for these minerals. Based on analyses of Luo-caught insects, just three crickets would provide an individual’s daily iron requirement.

Gram for gram, crickets or grasshoppers can be more nutritious than an equal quantity of beef or pork, says Victor B. Meyer-Rochow of Jacobs University in Bremen, Germany. One reason: Water constitutes a high percentage of meat, he says, whereas insects tend to be drier. Many insects also are richer in minerals than many meats, such as hamburger, his data show. And most lipids in bugs tend to be long-chain, unsaturated fats—healthier types than those predominant in conventional livestock.

A comprehensive survey of bug nutrients appears in the 2005 book Ecological Implications of Minilivestock: Potential of Insects, Rodents, Frogs and Snails. It reports published values for calories, protein, fat and fiber in most major species of edible insects. Additional tables summarize the potential of these bugs to contribute important amino acids, minerals, healthy fatty acids and vitamins to the diet.

The data were gleaned by Sandra G.F. Bukkens, now an independent nutrition consultant based in Barcelona, Spain. Overall, she says, “I was pleasantly surprised. Insects were far more healthy than I expected.”

Many insects had a fairly high concentration of essential amino acids—types that humans need but can’t make. These include lysine and tryptophan, two that tend to be limited in traditional diets in the developing world. The quality of insect proteins is usually good too, compensating, Bukkens says, for what is lacking in largely vegetarian diets.

Despite this upbeat assessment, Bukkens isn’t pushing insects on her family. “I’ve eaten them, but I’m not particularly keen about them,” she says. If food were limited, she would “eat anything. But since we have plenty of meat in developed countries, I don’t see why we should switch to insects.”

Even DeFoliart, whom many refer to as Mr. Entomophagy, admits to never cooking insects at home. In fact, his daughter once cajoled her mother into sampling a roasted cricket. When his daughter offered mom a second, DeFoliart recalls with a chuckle his wife’s reply: “Oh no, I’ll have to rest awhile.”

Clean and green

Diners who want to reduce the size of their environmental footprint might reassess their aversion to bugs, DeFoliart says. Insects typically eaten by people are vegans—at least for much of their life cycles, he says—and generally “clean-living in their choice of food and habitat.” Moreover, edible insects can forage on a far wider range of plants than do traditional meat animals. As such, he says, bugs can tap food sources normally worthless in conventional meat production, such as cacti, bamboo shoots, mesquite and woody scrub brush.

What’s more, insects turn more of what they eat into tissue that can be consumed by others. For crickets fed diets comparable in quality to the feed given to conventional Western livestock, diet conversion efficiency is about twice as high as for broiler chicks and pigs, four times higher than sheep and nearly six times higher than steers, DeFoliart reports. Insects’ quick reproduction and high fecundity makes them look even more environmentally attractive. For the crickets, DeFoliart has calculated, this translates into “a true food conversion efficiency close to 20 times better than that of beef.”

Gracer likens these differences to gas-guzzling versus gas-sipping vehicles: “Cows and pigs are the SUVs of the food world. And bugs—they’re the Priuses, maybe even bicycles.”

And bugs can be raised sustainably, the U.N.’s Durst says, pointing to an industry that has sprung up in northeast Thailand since 1999. Entomologists and agricultural extension agents at Khon Kaen University developed low-cost, cricket-rearing techniques and offered training to local residents. Currently, 4,500 families in Khon Kaen Province raise crickets, as do nearly 15,000 others elsewhere around the country, Khon Kaen entomologist Yupa Hanboonsong said at the recent meeting organized by Durst.

A single family can manage cricket rearing as a sideline activity without outside help, needing only a few hundred square feet of land. The 400 families in just two local villages produce some 10 metric tons of crickets in summer, the peak yield period. As the weather cools, yields may eventually fall by 80 percent or more. Still, that translates to extra, year-round income of $130 to $1,600 U.S. a month per family, Hanboonsong says. That’s quite a windfall for residents of one of Thailand’s poorer regions.

Most of their farmed crickets go to big city markets, like outdoor stalls in Bangkok. Hanboonsong says, however, that some are exported to neighboring cricket-consuming nations, such as Laos and Cambodia. Thai families also farm ants, another popular edible insect. And her Khon Kaen colleagues have just developed new rearing techniques for farming grasshoppers and the giant water bug (a Thai favorite). Indeed, Hanboonsong’s survey of Thai insect consumers found that 75 percent eat bugs simply because they’re tasty—especially as a snack with beer.

Bug farming gets around the problem that most insects are quite seasonal, Durst says. It also reduces pressures on wild populations. But data reported at his conference didn’t turn up much evidence of insect overexploitation in Thai forests. In fact, he says there were suggestions that increased entomophagy might pay bonus ecological dividends. For instance, it might make local villages better stewards of their environment because of the potential for collecting marketable insects.

There was even talk of how people might be marshaled to harvest insects for food in areas plagued by pests, substituting people for pesticides to protect crops.

It’s not far-fetched.

Hanboonsong reported that when chemical insecticides didn’t rout locusts from corn fields 30 years ago, the Thai government launched a campaign (including recipes) to collect and eat the pests. Although locusts had not previously been among the 150 species of bugs in the Thai diet, residents took up the challenge. Today, locusts are no longer a pest, and some farmers now plant corn as bait for the bugs, which they supply to local markets.

Biotech bug burgers

Durst suspects that two major facets of insects continue to turn many American and European diners off: concerns over hygiene and the fact that the critters look like—well, bugs. Hygiene can be dealt with by cleansing the outside of bugs thoroughly and emptying or even removing their guts. More difficult is camouflaging their antennae, buggy eyes and legs, or perhaps the fact that some look like soft, overly puffy worms.

Dutch scientists think they may have a solution to both impediments. They’re using biotechnology to produce vats of insect cells—just isolated cells. The researchers described their efforts last year in Biotechnology Advances.

The goal, explains Marjoleine C. Verkerk of Wageningen University, is to produce a sanitized source of bug proteins that can be dried and added to breads or perhaps molded into pseudo-burgers. Her team is mass producing isolated ovary cells of silkworms, fall armyworms, cabbage loopers and gypsy moths.

Grown in a bioreactor, these cells won’t support the growth of viruses or turn on cancer-triggering genes, things they could do in a whole bug, her group notes. As the researchers analyze the nutrient content of these cells, Verkerk has also begun to survey consumer attitudes on fortifying conventional fare with insect-derived materials. It remains a bit of a tough sell, she admits.

A Japanese consortium has a more far-out use for insects: space food.

Although trained as a chemist, these days Masamichi Yamashita says, “I prefer to be called a ‘space farmer’ wishing to fly to Mars.” At 60, he’s unlikely to be called up as an astronaut. So he’s doing the next best thing. Through his work at Japan’s Institute of Space and Astronautical Science in Sagamihara, he’s helping design a habitat that will allow future generations to survive years aboard cramped spacecraft or planetary outposts.

Key to the effort will be integrating bugs as a potential source of food and of natural plant-waste recycling for astronauts, his team argued a few months back in Advances in Space Research. He and his colleagues are developing an ecosystem that includes pupae of silkworms and hawk moths as sources of food. These metamorphosing insects—especially the silkworms—are popular in Japan and other parts of Asia.

Their taste? “I ate soft-shell crab in Washington, D.C., once,” Yamashita says. “That might be close.”