Tag: insects as human food

Eating Insects Part III: Gathered or harvested insects vs. farmed insects

In previous posts, I have discussed Questions 1) and 2) with the answers that 1) I think that getting people to eat insects will not be an insurmountable barrier and 2) there are specific concerns that must be addressed to assure people that the insects that they are eating are of proven (vetted) food value and that they are safe in accordance to food safety guidelines.  I expressed special concern about getting right the analytical methods that provide information for food labels (proximate analyses) of insects to be used as food AND I suggested that careful scientific experiments needed to be done to demonstrate the efficacy and bio-availability of insects on a per case basis (i.e., what we learn about how bio-available cricket protein may be for humans does not translate exactly to the bio-availability of mealworms or some other insects.

This leads to my third question from the paragraph in the original blog post on eating insects: gathering vs. farming.

Some Basic Questions and Organizing Principles: 1) Will social or cultural constraints make it unrealistic to use insects as human food? 2) Does the food value and food safety of insects impose impossible constraints? 3) Will gathering insects from nature allow us to make a significant “dent” in the needs for human food? 4) Will systems of farming insects become feasible to make significant advances in the use of insects as human foods? 5) How far can insect mass-rearing go towards allowing us to produce enough quality insect biomass to have a significant impact on the growing needs for food?

In the FAO-sponsored paper by van Huis et al. 2013, the authors make a case for the wide-spread acceptance and cultural tradition of using insects as food for people.  The photographs in this publication are dazzling, and the presentation of the insects makes them most appetizing.  However, most of the insects depicted in this paper are gathered (harvested from nature or as side-products from agriculture.  At this level of making insects available, there is total dependence on existing populations of insects, just as fishing and hunting are used to provide human food from the oceans, fresh water, and from the wild, in general.  Clearly there problem with reliance on gathered insects will meet with the same barriers that fishing and hunting have met when human populations rose to levels that exceeded the supply from nature alone.

silkworms (Bombyx mori) feeding on mulberry leaves

silkworms (Bombyx mori) feeding on mulberry leaves

 

 

Silkworm pupae and emerging adults

Silkworm pupae and emerging adults

 

 

Of course, this gave rise to agriculture.  So the next step that far-thinking “insects as food advocates” suggest is agricultural production of insects: farming insects to be used as human food.  There are several possible forms of “insect farming:” 1) field operations where production takes place in agricultural fields or in greenhouses, 2) production of feeder insects as side-products of existing programs or insect production that is in place with other functions, and 3) in systems where insects are reared for food purposes as the primary goals.

  1. Producing edible insects as a field operation: often our mono-culture system of agriculture results in production of large biomasses of insects that are pests in our crops.  So a possible avenue for mass-production of insects in the field could be a controlled locust swarm where an optimized crop of grass could be grown to deliberately serve as a food for locusts, which would be harvested at appropriate times.  Buildups of locusts and other crop pests take place NOT under human control.  If the pests’ biology could be better understood with all the conditions that lead to massive pest outbreaks managed, this could be a low-input form of insect farming.  Obviously, this is a speculative issue, and much, much more understanding of the natural cycles of pest build-up must be developed.
  2. The production of feeder insects as an outgrowth of existing insect production systems has the advantage that a substantial base of knowledge exists for producing certain kinds of insects.  Silkworms have been domesticated for 5000 years, and their mass- production for silk has long been a practice throughout Asia and more recently, the Middle-East and parts of Europe (and even in the Americas to a limited extent).  It happens, too that silkworms are already a well-accepted food for people, and the pupae, once they have spun their cocoon, can be harvested for food for people.  If the cost of producing silkworms were further reduced with an artificial diet technology that could replace the mulberry with a cheaper food while retaining the mulberry flavor with an extract, it is possible (though challenging) to greatly increase silkworm production, make silk less expensive, and make considerable biomass of tasty silkworm pupae available.  Honeybee drones have been used as as food for people and other organisms, and the cost of producing drones is supplemented by the use of honeybees as 1) pollinators, 2) sources of honey, 3) sources of wax, and 4) other products that can be value-added ALONG WITH DRONES AS HUMAN FOOD.  Again, like with silkworms, this possibility would call for development of technology that would reduce the cost of amplifying bee populations.  In light of the current problems with colony collapse disorder (CCD), this prospect seems challenging, but I feel that too little is understood about nutritional replacements of pollen and nectar, so I can see a possible increase in honeybee production.
  3. Some other insects that are currently produced as feeders, include crickets and meal worms, drosophilid flies, horn worms, among others.  Improvements in mass-rearing these and other potential feeder organisms, can result in reduced costs of production of feeder insects for human food.  This topic requires far more discussion, some of which I will do in a future blog post.  It should be noted that only a few researchers have treated with actual scientific studies the topic of the efficacy of the production and use of feeder insects as human food: this leaves most of the considerable attention that has been given to this topic in the category of speculation.  An example of what I mean by scientific studies is the Lundy and Parrella (2015) paper titled, “Crickets are not a free lunch…:”  These authors did a systematic study of utilization of various quality foods by crickets (Acheta domesticus).  Statements in the popular literature, on websites, and in proposals for funds to support enhancement technology for producing crickets (and other feeder insects) on low quality foods, including portions of waste streams.  Lundy and Parrella showed that the claims by many insects as human food advocates that crickets have a tremendous potential for turning low quality foods into high quality, high nutrient insect biomass.  These authors showed that there are definite limitations to crickets’ ability to make the kind of conversions that they are often touted to make.  I will treat this concept of how much we should expect from insects to make the nearly magical transformations in a near future blog post on the virtually alchemy expectations that are touted for insects.

 

Lundy M. E., Parrella, M. P. (2015) Crickets Are Not a Free Lunch: Protein Capture from Scalable Organic Side-Streams via High-Density Populations of Acheta domesticus. PLoS ONE 10(4): e0118785. doi:10.1371/journal.pone.0118785

van Huis A, van Itterbeeck J, Klunder H, Mertens E, Halloran A, Muir G, et al. Edible insects: future prospects for food and feed security. No. 171. Food and Agriculture Organization of the United Nations (FAO), 2013.

Eating Insects: Part II

Sub-Title: Insects as food for humans: the role of insect rearing Part II

 

 

Price of crickets available online. The cost of a 50 g ration of protein (recommended by FAO/WHO for human adults) is about $12.50 US dollars.

Price of crickets available online. The cost of a 50 g ration of protein (recommended by FAO/WHO for human adults) is about $12.50 US dollars.

In the previous blog page on this topic, I gave an overview of the potential for using insects as human food to make a significant impact on the goal of meeting the growing need for food for a population of humans that is expected to rise from about 7.5 billion in 2016 to more than 9 billion people in 2050.  I introduced the following paragraph and I answered the first question about whether enough people would be willing to accept a new food source to make a difference.  I answered this affirmatively, meaning that based on current cultures and anticipated needs, people WILL be willing to eat insects as a significant part of their diet.  Now, reminding the reader of the overview paragraph, I will discuss the second question.

Some Basic Questions and Organizing Principles: 1) Will social or cultural constraints make it unrealistic to use insects as human food? 2) Does the food value and food safety of insects impose impossible constraints? 3) Will gathering insects from nature allow us to make a significant “dent” in the needs for human food? 4) Will systems of farming insects become feasible to make significant advances in the use of insects as human foods? 5) How far can insect mass-rearing go towards allowing us to produce enough quality insect biomass to have a significant impact on the growing needs for food?

Although standards will differ from country to country and the influence as such organizations as FAO (Food and Agriculture Organization of the United Nations) and WHO (World Health Organization)–(not to mention such organizations as the USDA and the US Food and Drug Administration will provide guidelines or regulations, the issues of food value of various insects and food safety of insects intended to be incorporated into the human food chain must be much better understood than they are currently.

As for food value of various insects, a very well-cited work is the paper by M. D. Finke (2002) which provides proximate nutrients (gross composition of proteins, lipids, carbohydrates, and minerals) of several commonly used feeder insects.  Other papers are appearing with increasing frequency in both entomological journals as well as food science journals.  The papers of Longvah et al. 2011 and Zhou and Han 2006 are good examples of nutritional analyses of insects currently eaten by people.

However, an important caveat is that there is a disparity between what is IN the insects versus what is AVAILABLE to a person eating the insects.  The concept of bioavailability is still poorly explored, though papers such as the one cited here by Xia et al. (2012) tackle the question of how well a target organism can access the nutrients.  The topic of factors that govern bioavailability, though fascinating, is too involved for the current blog entry.  I treat this in more detail in my book (Cohen 2015), but suffice it to say that not all nutrients can be accessed equally well: so a protein that may be present in an insect may not get digested or absorbed because it is surrounded by indigestible cuticle, or it may have a sequence of amino acids that defies digestion.  The same question of bioavailability applies to other nutrients such as vitamins and lipids.  Testing the bioavailability and other aspects of food value of insects requires very specialized expertise, and even if a rat or rabbit model is used, the results may not translate into the human context.

One more point about proximate analysis (something like the food labels on peanut butter or milk cartons): the methods and competency of analysis are very crucial.  I have seen several treatments of insects’ food value presented, and when difficult to measure nutrients such as proteins are presented, there is often an over-estimation of the amount of protein present.  When researchers use standard methods such as elemental nitrogen, they are NOT directly measuring the actual protein.  For many foods (soy products, milk, vertebrate-derived meats, for example), using elemental analysis of total nitrogen and multiplying by a correction factor gives a good estimate of the protein value of that food.  HOWEVER, in insects, total nitrogen (elemental nitrogen) does not reflect exactly the true protein content due to false elevation of nitrogen levels such as the nitrogen in the cuticle and nitrogenous wastes like uric acid, which all give a value that increases the nitrogen but does not increase the protein.  This point has long troubled me because it causes an inflated value for the protein in most insect species.  The other point here is that the quality of the protein is not reflected by the elemental nitrogen analysis.  Low quality proteins that are poor in some of the essential amino acids would give a false high score in a protein evaluation.  Therefore, the appropriate analytical evaluations and interpretations are absolute essentials in judging the food value of insects for people.

The other issue of food safety raises many more questions that can be very challenging.  For example, crickets which are commonly used by entomophagy enthusiasts can carry lots of potentially dangerous microbes, and the concept of using soldier flies fed poultry feces brings with it challenges to deal safely with the Salmonella and other gut microbes know to be present in poultry.  Several websites exist that provide recipes for insects, and some of them are very responsible about suggesting that the insects be cooked by blanching in boiling water for at least two minutes.  These types of standards must become firmly established, vetted, and publicized before the questions of food safety can be put to rest.

This is only a cursory discussion of the issues of food value and food safety, but they are ones that current and future insects as food enthusiasts must be prepared to address.

Finke, M.D. 2002. Complete nutrient composition of commercially raised invertebrates used as food for insectivores. Zoo Biology, 21(3): 269–285.

Longvah, T., K. Mangthya, and P. Ramulu.  2011.  Nutrient composition and protein quality evaluation of eri silkworm (Samia ricinii) prepupae and pupae.  Food Chemistry.  Food Chemistry 128:  400–403.

Zhou, J. and D. Han.  2006.  Proximate, amino acid and mineral composition of pupae of the silkworm Antheraea pernyi in China.  Journal of Food Composition and Analysis 19: 850–853.

Xia, Z., S. Wu, S. Pan, and J. M. Kim.  2012.   Nutritional evaluation of protein from Clanis bilineata (Lepidoptera), an edible insect 58J Sci Food Agric.  92: 1479–1482.

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