This time our guest blog comes from Euan MacAuslan – Food Safety and Freelance Trainer, Author & Environmental Health Practitioner.
You can find out more from Euan here at LinkedIn .
About 40 years ago I was an Environmental Health Assistant in the Royal Army Medical Corps at the then School of Army Health. One of my roles was to train troops about medical entomology and pest control relevant to where they may be posted to in the World. In addition, I was responsible for the insectary full of creepy crawlies deemed to be vectors of disease. It was during my time there that I purchased a book called “Why Not Eat Insects?” by Vincent M. Holt. Why not indeed! Well, quite simply it had the potential to spruce up composite rations we consumed in the field. Food allergens were not even discussed back then.
If someone is allergic to shellfish and crustaceans, it may ring true that they could also be allergic to edible insects. Some constituents of insects are also found in shellfish and crustaceans. These constituents are summarised in a simplistic way below. But ,what is clear, much more research is required for a definitive answer to questions, such as:
- “If someone is allergic to crustaceans and shellfish, can they eat insects?”
- “Can a shellfish or crustacean allergic consumer eat meat from livestock fed on insects used in animal feed?”
- “What are the implications for allergen labelling if the ingredients contain constituents of insects?”.
In the UK there is a small, but noticeable, move away from animal protein-based foods to plant-based foods. How long will it be before insects are accepted as a standard menu or recipe item? For environmental reasons ground insects are also being used in animal feed to reduce the carbon footprint associated with beef production.
Did you know insects already form a significant part of diets around the world and the global edible insect market is set to exceed £406 million by 2023? (The Independent )
The Natural History Museum in London has a website page headed “Eat Insects and save the World”. What kind of insects? These include crickets, mealworms, grasshoppers, silkworms and giant ants. Insects are generally rich in vitamins like iron and zinc, as well as essential fatty acids like Omega-3. They are also low in fat and a good source of protein – a 100-gramme portion of crickets can contain as much as 69 grammes of protein. Insects require 12 times less feed than cattle.
In 2018, the Evening Standard published an article about where to eat insects in London’s restaurants. Ethnic shops and market stall have for many years sold edible insects. It was not until 2018 that Sainsbury’s became the UK’s first supermarket chain to sell edible insects. BBQ Crunchy Roasted Crickets were sold in 250 of the chain’s supermarkets. Now, many supermarket chains sell edible insects, including cricket flour.
Increasingly, around the World (including the UK and EU) cattle feed is being made from insects. Insects are replacing fishmeal.
Did you know that shellfish is a known risk factor for Cricket Anaphylaxis ?
A sugar called Chitosan is obtained from the hard outer skeleton of shellfish, including crab, lobster, and shrimp. In addition, it is found in insects. It is used for medicine. Research has shown that it is not thought to cause a problem. Various papers are inconclusive in their research findings about links with allergies. Others may be more positive, but more investigation is required.
Chitin is an amino polysaccharide polymer occurring in nature. It is the building material that gives strength to the exoskeletons of crustaceans and insects. Through enzymatic or chemical deacetylation, chitin can be converted to chitosan. The Anaphylaxis Campaign advises that “Chitin, derived from shellfish shells, is used in commercial “fat absorbers” such as Chitosan HD, and should be avoided. Moisturisers can also contain shellfish-derived chitin. Some calcium supplements may contain ground oyster shells.”
Chitinase degrades Chitin in digestion in humans. It is thought that for some humans, Chitinase may lead to allergic reactions. However, the precise roles of Chitosan, Chitin, and Chitinase in causing allergic reactions in humans are still under review. One published paper reports on allergic reactions following the consumption of insects. It states that within a given area of Thailand “approximately 7.4% of people experienced an adverse reaction indicative of an edible-insect allergy and 14.7% of people experienced multiple adverse reactions indicative of an edible-insect allergy. Furthermore, approximately 46.2% of people that already suffer from a known food-based allergy also experienced symptoms indicative of an allergic reaction after insect consumption.”
Like shrimps, insects are arthropods. It is known that crustaceans and shellfish can cause severe allergic reactions. A major trigger of shellfish allergies is tropomyosin (a muscle protein). The protein sequence of tropomyosin is similar in insects and crustaceans, and people with shellfish allergies may also react to insects. It could be that tropomyosin is the major hazard when eating insects. Ground insects may be used as ingredients in protein drinks. Tropomyosin has been described as an important food allergen in shrimp, lobster, crab, oysters, squid, and other invertebrates. Allergic reactions to shellfish and molluscs are often cross-reactive, which may be explained by the highly conserved amino acid sequences of tropomyosins among invertebrates, but vertebrate tropomyosins are not known to be allergenic. A paper entitled Allergenic tropomyosins and their cross-reactivities discusses this matter further.
So where does all this leave the issue of labelling? For many in a range of disciplines connected with allergies and allergen controls, and also for an increasing number of consumers, the 14 allergens that in the UK legally need to be listed in ingredients or on menus if present are wholly inadequate. Declaration of allergens varies across the World. In Japan, for example, there are seven designated foods which manufacturers are legally obligated to indicate on the label when they are included as ingredients. These foods have been selected either because a significant portion of the population is allergic to them, or due to the severity of reaction symptoms. They are shrimp, crab, wheat, buckwheat, egg, milk, and peanut. But it is also recommended that a further 20 foods are listed!
Where does this leave edible insects as allergens and allergen declarations? I don’t expect any changes soon in the UK, but it is worth keeping under review on as animal rearing and dietary habits change.
