Chapul, Exo and Jungle – three protein bars making their way to supermarket shelves – have one thing in common: crickets. All three include cricket flour, which is touted by their manufacturers as an environmentally friendly alternative to milk or soy protein.

Insects offer a complete protein and a rich source of vitamins, minerals, fat and fiber, and they require less space and water to grow than traditional livestock, such as cows and chickens. They also produce less ammonia and fewer greenhouse gases and can feed on a variety of organic matter, including food waste.

Farmed bugs can also offer a small business opportunity, but current US regulation of insect products is murky. So companies face a twofold challenge: convincing people it’s OK to eat bugs while also trying to find a legal way to produce edible critters.

The United Nations Food and Agriculture Organization sees insects as a potential low-impact source of protein for a food insecure world, which is expected to reach a population of 9 billion by 2050. A key technical hurdle remains in bringing bugs to the table, however: overcoming disgust.

“One of the major, if not the major impediments to large scale increases of human insect consumption, is the strong rejection of insects as food by most of the world’s population,” writes Paul Rozin in a forthcoming paper, Determinants of Willingness to Eat Insects in the USA and India, to be published in the nascent Journal of Insects as Food and Feed.

Rozin teaches at the University of Pennsylvania and has written widely about the psychology of disgust. He is also on the international advisory board of the Nordic Food Lab, a research operation established by Rene Redzepi, founder of Michelin starred restaurant Noma in Denmark.

Rozin said aversion to insect-eating may stem from a belief that food containing bugs is dirty, unpalatable, texturally unpleasant or simply culturally unacceptable. That perception varies by insect, with the cockroach perceived as the least desirable and ants the least offensive. Rozin writes the disgust associated with a specific type of bug like the cockroach may be due to “its perceived moistness or viscosity, which probably accounts for the fact that the caterpillar and mealworm were not as acceptable as the drier and crunchier ant”.

These types of aversions may hold true even in places where insects are commonly eaten. In Thailand, where it may be common to include water beetles and crickets in a diet, insects consumed have typically been gathered, not farmed, and are limited to what’s readily available. A 15-year test project there resulted in the creation of 20,000 cricket farmers, with a thriving export market.

But that doesn’t mean people there are ready to eat maggots or fly larvae, which may be among the most efficient and dense sources of insect protein.

“Even in Thailand, eating fly larvae is considered not really human food,” said Nanna Roos, a professor of nutrition at the University of Copenhagen who is conducting a similar insect test-farming project in Kenya. She said the same holds true for Sardinians who eat “Casu marzu”, also known as maggot cheese. People who eat the cheese, which does in fact contain maggots, would be unlikely to eat the maggots separately from the cheese.

Rozin’s survey found that men were more willing to eat insects than women and that perceptions of texture and cleanliness factored in significantly to decision making on eating bugs. He suggested that sushi, which may seem unappealing to those who haven’t grown up with it, could offer a model in making bugs acceptable as food.

While it may seem like a novelty to those unaccustomed to eating insects, this trend is perhaps as old as eating itself. People consume 2,000 species of insects as food across Asia, Africa, and South America, as well as to a lesser extent in Europe and the US.

Some estimates suggest as many as 2 billion people eat bugs as a part of their diet, though that widely cited figure refers to the number of people in cultures where insect-eating is accepted, not necessarily to the number of bug-eaters themselves.

Small children tend to eat everything they encounter, including dirt and insects, so eating bugs may simply be a matter of exposure and experience. “Everyone in this culture is trained not to do that. You have to reverse the training,” Rozin said.

Should bug-eating find a broader audience, insect farms will have to catch up. In the US, for example, which seems to be leaning toward crickets as the edible bug of choice, cost is still prohibitive.

Mark Finke, who has a background in entomology and nutrition and has developed and tested pet foods for Alpo, Ralston Purina, and PetSmart, said the cost of cricket protein is currently five to 10 times the cost of the same unit of chicken protein. And mechanized systems for harvesting and cleaning them have not been created. “None of that exists for insects yet,” said Finke.

In July of this year, the USDA Small Business Innovation Research program awarded a $100,000 grant to All Things Bugs – which wholesales cricket powder for $35 a pound – and its lead researcher, Aaron T Dossey. The grant is intended to help Dossey mechanize his operation and drive down cost as a model for others interested in doing the same. The company received startup funding in 2012 from the Gates Foundation “to develop a method for the efficient production of nutritionally dense food using insect species”.

Sonny Ramaswamy is the director of the USDA’s National Institute of Food and Agriculture, which awarded the grant. Ramaswamy also happens to be an entomologist with personal interest in the subject. “I love to cook, first. And I also love to use insects in my cooking from time to time,” he said. He added that the legal pathways for insects to be used as ingredients or additives in the US are not entirely clear.

It is currently legal in the US to sell whole insects for human consumption if they are raised for that purpose and if the scientific name is printed on the packaging. But it is not legal to sell insects as animal food for animals that will be consumed by humans, according to Ramaswamy. It is also not legal to grind up insects and extract the protein for sale as a standalone product.

Reading the label of a Chapul bar he happened to have nearby, Ramaswamy pointed out that the amount of cricket powder it contains is actually very small, putting it in a gray area in terms of regulation.

“Technically speaking, what the FDA has not ruled on is where this is at in regards to these sorts of products, and therefore the individuals that are selling these things are caught in a sort of regulatory limbo,” he said. “We do not have regulatory clarity.”

Once insect farming can be cheaply mechanized, protein from insects could conceivably have the greatest impact in countries with lower GDPs, where political unrest or environmental problems such as drought make for an insecure food supply.

The market in the US for insect-based foods will likely remain limited to adventurous eaters and people who already use other types of dietary supplements.

Ramaswamy said he doesn’t anticipate many people heading to the supermarket saying, “I’m going to get me a couple of pounds of grasshoppers.”