Black Soldier flies for dinner? Nutritional benefits highlighted despite food safety and allergy challenges

30 Oct 2020 --- Potential food safety risks are currently the most significant barrier preventing the human consumption of Black Soldier fly larvae (BSFL). This is according to a scientist from the University of Queensland, Australia, whose comprehensive review details how BSFL’s nutritional qualities could make it a promising foodstuff.

In addition to safety concerns, aspects including allergens, consumer attitudes, technofunctional properties and product applications must be addressed before human consumption of BSFL is widespread. 

“Just like meat, it contains all the nutrients humans need for health. The larvae is richer in zinc and iron than lean meat, and its calcium content is as high as that of milk,” says Louw Hoffman, author of the review. 

One key reason why BSFL is already so widely used as a feed source for animals is its diversity of micro- and macronutrients. 

Obtaining different nutritional profiles
BSFL is typically high in both protein and fat, with protein contents ranging from 30-53 g per 100 g dry matter (DM) and lipid contents ranging from 20-41 g per 100 g DM. 

Meanwhile, chitin predominately acts as fiber in the human body and consists of 2-9 g per 100g of DM BSFL.  

Notably, the nutritional composition is affected by environmental factors and the larvae’s age, meaning that different nutritional profiles can be obtained for different applications. 

For example, as the larvae ages, protein seems to decrease as fat increases. Meanwhile, chitin is relatively low during the prepupae stage and then peaks during the pupae stage. 

Earlier this month, Entoprotech partnered up to investigate the anti-inflammatory properties of Black Soldier fly fat, with potential nutraceutical applications. Black Soldier flies have different nutritional compositions in each life-stage. 

Challenges arise
However, harvesting prior to pupation would introduce a challenge in harvesting the larvae from the waste feed prior to their prepupae stage. This is when they naturally migrate out of their feed source on their own, details Hoffman. 

Additionally, there is currently very little information regarding the functionality of insect proteins in general, and even less on BSFL proteins.

Meanwhile, the lack of standardization in protein isolation methods prevents the determination of the functional properties of insects. 

“Preliminary studies investigating the functional properties of select insect flours and proteins have found that the extraction method influenced the functionality of the extracted insect proteins,” notes the study.

The challenge going forward is to improve the fractionation methods in order to yield optimum amounts of protein, fat and chitin. This must be while maintaining the functionality and integrity of each fractionated component.

Food safety concerns
According to the review, the largest concern regarding BSFL is the food safety risk associated with growing the larvae on waste. 

“While the fly can clean up toxic waste including heavy metals, it’s also recommended flies bred for human food be fed a clean source of organic waste,” notes Hoffman. 

This would reduce the potential associated risks such as heavy metal uptake and potential pathogenic microorganisms. 

Notably, there is already sizable research regarding the safety of using BSFL for animal consumption when reared on a wide range of waste substrates. 

This could also be relevant for human food, with post-harvesting processes such as blanching being used as an effective safety tool.

Mitigating allergic reactions
Another important consideration is whether consumers may have allergic responses to BSFL. There are already reported cases of allergic responses when ingesting carmine dye, which is an insect-based food coloring.

Additionally, there have been reported cases of allergic reactions in China, where eating silkworm pupae is commonplace. 

While some allergenic proteins are stable in heat processing and digestion, others are readily inactivated. In some cases, heat processing might also cause proteins to become more allergenic. 

In the case of mealworms, heating helps reduce allergic reactions, but it is unknown if this would be the case with BSFL. 

Another avenue for mitigating allergens could be hydrolysis, which has been used as a technique to reduce the allergic reaction to food proteins such as soy and crickets. Many cultures have a stigma against eating certain insects. 

Overcoming consumer perceptions
Finally, the widespread human consumption of BSFL would mean changing many consumers’ mindsets. 

While the UN’s Food and Agriculture Organization (FAO) estimates that two billion people around the world already eat insects regularly as part of their diet, many cultures have a stigma against eating them.

“The biggest factor that prevents fly proteins being used in our food supply is Western consumers’ acceptance of insects as food. We will eat pea or oat milk, even lab-grown meats, but insects just aren’t on Western menus,” notes Hoffman. 

However, consumers – who are increasingly eco-conscious – may be swayed by the environmental arguments for larvae consumption. It’s estimated that less than half a hectare of BSFL can produce more protein than cattle grazing on around 1,200 hectares of cattle or 52 hectares of soybeans.

“If you care about the environment, then you should consider and be willing to eat insect protein,” concludes Hoffman. 

In February, the International Platform of Insects for Food and Feed observed that increasing numbers of Europeans are becoming interested in trying insect-based food products. 

Meanwhile, a European policy shift could pave the way for edible insects’ first “novel food” authorizations next year.

Edited by Katherine Durrell