Category: Uncategorized (Page 2 of 3)

Insects as Human Food Part V: The Role of Mass-Rearing

So far, I have discussed several aspects of feasibility and practicality of using insects as a significant source of human food.  I have cited several documents that treat this topic, some with optimism, others with reserve, and I have expressed an overall reserve about the prospects.  I had expressed my opinion that the cultural objections would not be insurmountable, but instead, I suggested that the practicality of such a vision’s becoming a reality was in the production system.  I pointed out that gathering existing insects would not meet the growing need for human food as our population increases from more than 7 billion today (2016) to more than 9 billion by 2050.  I further discussed the gaps in our background that would allow us to farm insects in a production system that is derived from current insect farming such as cricket, mealworm, and silkworm production.

This leads to my major area of expertise: insect rearing (or MASS-REARING).  I have devoted the past 40 years of my life to better understand and contribute to rearing science and technology, so I feel that my views come from a background of serious study of this topic.  This includes my writing more than 100 papers on the topic of rearing, and my having read and reviewed more than 1000 papers on rearing (as an author, editor, and reviewer).

In this experience, I have studied the most successful and unsuccessful efforts to develop mass-rearing technology.  And with this background, I can say that there have been many pitfalls that had to be overcome for mass-rearing systems to become practical realities.  Probably the first true mass-rearing system was developed for screwworms (this somewhat neglects the rearing of silkworms on mulberry leaves, which I discuss elsewhere on this website), and it was not until the full-scale system could be developed over more than two decades of research that the sterile screwworm technique could be applied to a field-scale test.  With tephritid fruitflies, several systems are in operation, but these systems took decades to develop.  Other mass-rearing systems include the pink bollworm sterile release program, the boll weevil program (an area-wide system in the southern US), and several biological control systems.  In every case, it took at least a decade or more of cost and labor-intensive research to get the systems to a point that could be called true “mass-rearing.”  And as I treat in my book on Insect Diets: Science and Technology (2nd Edition), the actual biomass produced in any of these systems falls far short of what could make a significant impact on impending world hunger crises.

In all the cases of successful development of true mass-rearing systems, the most important deciding factor (as to whether or not the system would succeed in achieving mass-rearing) was automation.  Along with the automation advancements, there had to be developments of diets/feeding systems, diet presentation systems, containerization, environmental optimization, management of microbial factors (contaminants and symbionts = bad microbes and good ones), management of potential for genetic deterioration, and waste management (thousands of pounds of scales produced as potentially hazardous waste from pink bollworm production and tons of carcasses, spent food, deteriorated containers, etc.).

These are all parts of mass-rearing systems that required often exquisitely elaborate and deeply thought out research on how to deal with these issues.  Just the most basic example faced in mass-rearing facilities is how to deal with toxins like formaldehyde or sodium hypochlorite (bleach) in surface-sterilizing eggs.  Just this simple sanitation question requires detailed and well designed experiments or tests that guide rearing system managers as to how to deal with these and myriads of other problems in establishing and running complex rearing systems.

It is these issues to which this website is devoted.  And I will discuss some of these issues further in the next few blog pages.  Please stay tuned.

Insect Rearing vs. Insect Farming: Part I

http://www.csrtimys.res.in/structure/seri-engineering-division Central Sericultural Research & Training Institute (CSRTI), Mysore [An ISO 9001 : 2008 Organisation] CENTRAL SILK BOARD - MINISTRY OF TEXTILES - GOVT. OF INDIA

http://www.csrtimys.res.in/structure/seri-engineering-division
Central Sericultural Research & Training Institute (CSRTI), Mysore
[An ISO 9001 : 2008 Organisation]
CENTRAL SILK BOARD – MINISTRY OF TEXTILES – GOVT. OF INDIA

I

 

 

 

 

 

silkworms-in-viet-nam

Raising silkworms Hoi An Quang Nam, Vietnam www.gettyimages.ae

I have been trying to make useful distinctions between insect farming and insect rearing.  The differences that I suggest are that while farming is lower input and less controlled than rearing, rearing can usefully be distinguished with the incorporation of artificial diet.  While silkworms have been farmed for nearly 5000 years on their natural host (mulberry leaves), and honeybees have been managed but allow to feed on natural (or wild) foods, rearing with artificial diets began in the 19-teens when Drosophila species were given modified banana with yeast and agar added.  This set the stage for artificial diet-based rearing, which has been developing over the past 100 years.  I realize that if you grow a pepper plant in your lab or green house, and use that plant to support a colony of aphids, you are in a sense rearing the aphids.  But you are limited in your control over the plant’s nutritional value to the aphids.

So the distinction that I am making is based largely on INPUT and CONTROL.  With pre-farming  activities hunting, fishing, and gathering, the foods and other items like clothing, tools, etc. were not processed at all or not very much.  The early humans probably started off killing small animals by hand, grabbing fish out of the water, and picking plant materials.  As they started to use tools for hunting, fishing, and harvesting, they started to have a little more control, but when they domesticated plants and animals, they had higher levels of control, more predictable outcomes, and they were becoming agriculturalists (farmers).  I see insect farming as having input and control over the intended products.  The next steps add the control of the insects’ environment, its food, which insects breed with one-another, etc.  This tendency towards control gives much more reliable outcomes, and my insistence upon making rearing into a more and more scientific process is in line with the concept of predictable outcomes.

In the film clip on this page, I show the silkworms that I have been rearing on artificial diet.  But also, I include an image of the efforts that silk producing countries are making at reducing the labor and expanding the scope of silkworm farming such as the mulberry field in India where automation and machinery are being adopted to increase the yield of mulberry per hectare of land.  The same engineering organization is adding as much automation as possible to silkworm production, compared with the production of silkworms in the facility in Vietnam (which is still a very impressive process, though it may date back to hundreds or thousands of years of silkworm farms).

More on these points in future pages.

Who’s Who in Rearing: Part I

Please note: these pages on who’s who in rearing are thematically related to the pages that I have been posting on eating insects.  I have taken a slight turn here to work into this website some background on the variety of people and programs where insect rearing is central.

Using mulberry bushes, rather than trees reduces costs of farming silkworms

Using mulberry bushes, rather than trees reduces costs of farming silkworms

 

 

 

 

http://www.tammachat.com/

 

 

 

Laotian woman sorting silkworms: throughout rural Asia, tens of thousands of families make their living rearing silkworms and harvesting raw silk

Laotian woman sorting silkworms: throughout rural Asia, tens of thousands of families make their living rearing silkworms and harvesting raw silk

 

  • Woman removes silk worms from mulberry leaves
  • Credit: Margie Politzer
  • Creative #: 165661631
  • Ban Xang Khong, Luang Prabang, Laos.
  • www.gettyimages.ae

 

 

 

 

Who Is Rearing Insects?

This section of my blog pages is intended to provide an overview of people and institutions that are conducting significant rearing operations.  It cannot cover every high performance rearing operation for several reasons: 1) I cannot know all the people and organizations that do rearing, 2) there are so many rearing operations in existence that there would be no room to cover them all, and 3) many of the operations are doing rearing that is proprietary (such as private companies).  Based on my knowledge of the rearing community, I have estimated that there are at least 10,000 (possibly 20,000) people around the world who make their living or spend most of their time rearing insects.  These people do their rearing as part of research in educational institutions, for production by private companies, as part of government programs, and in a surprisingly diverse number of domains.

After spending a quarter of a century as an insect rearing specialist in the USDA, Agricultural Research Service, I thought that I had a grasp of the scope of insect rearing.  But as a rearing consultant in a private company and later as coordinator of an insect rearing program at North Carolina State University, I have been surprised at the number and kinds of rearing efforts around the world.  Here is a brief list of types of rearing operations:

  1. International Organizations such as the United Nations, FAO (Food and Agriculture Organization), WHO (World Health Organization).
  2. Large federal government laboratories: for example, 1) the USDA has rearing presence in the Animal and Plant Health Inspection Service or APHIS, the 2) Forest Service, 3) the Agricultural Research Service, the 4) Canadian Forest Service, 5) Ag Canada, EMBRAPA, The Brazilian Agricultural Research Corporation, 6) the Australian Centre for International Agricultural Research, 7) French National Institute for Agricultural Research (INRA), 8) Department of Agriculture and Rural Development (Great Britain), 9) IRTA in Catalonia, Spain, 10) CIGAR in Africa (Nigeria, etc.), 11) IAR (Iran Agricultural Research), 12) Agricultural Research Organization, Volcani Center (Israel), 13) ARC or Agricultural Research Center, Egypt (under the Ministry of Agriculture and Land Reclamation), 14) International Food Policy Research Institute (China and Eastern Asia), 15) National Agriculture and Food Research Organization (NARO in Japan), 16) Indian Council of Agricultural Research (ICAR), and many, many others. My references are biased towards North America, but every nation in the world has its own (sometimes multiple) organizations or works within a consortium of countries or umbrella organizations to rear insects for protection of food, for medical purposes, or for research.
  3. State (or province) programs: in the US, for example, every state has its own department of agriculture or plant industry, and many of these have significant rearing facilities including some major rearing facilities.
  4. University rearing laboratories (no matter how small the college or university there are almost always rearing efforts that provide insects used as research and educational tools).
  5. Private Industry: 1) the companies that use insect rearing for their internal research and 2) the companies that produce insects directly for sales where the insects are used for food for other organisms, as biological control agents, as educational resources, and even as live creatures for various kinds of celebrations.

This list of various entities where rearing is practiced, sometimes on a major scale that employs dozens to hundreds of people in a single facility hardly expresses the scope and diversity of insect rearing operations.  Just imagine, for example, how much effort goes into rearing Bombyx mori for silk production.  Just in the silk industry in India alone, for example tens of thousands of families make their living in rural India by farming mulberry and rearing silkworms. I have included an interesting paragraph from the Gangopadhyay (2008) paper where sericulture is described.

From:  Sericulture Industry in India – A Review from India Science and Technology

By D. Gangopadhyay 2008. http://www.nistads.res.in/indiasnt2008/t6rural/t6rur16.htm

“Sericulture is both an art and science of raising silkworms for silk production. Silk as a weavable fiber was first discovered by the Chinese empress Xi Ling Shi during 2,640 B.C. and its culture and weaving was a guarded secret for more than 2,500 years by the Chinese. Silk was a profitable trade commodity in China. Traders from ancient Persia (now, Iran) used to bring richly coloured and fine textured silks from Chinese merchants through hazardous routes interspersed with dangerous mountainous terrains, difficult passes, dry deserts and thick forests. Though, commodities like amber, glass, spices and tea were also traded along with silk which indeed rapidly became one of the principal elements of the Chinese economy and hence, the trade route got the name ‘SILK ROUTE’. Even today, silk reigns supreme as an object of desire and fabric of high fashion. Being a rural based industry, the production and weaving of silk are largely carried out by relatively poor sections of the society and this aspect of sericulture has made it popular and sustainable in countries like China and India.”

It’s tempting to spend considerable time discussing the silkworm rearing industry because of its long-standing importance on the world stage for millennia, but the other aspects of insect rearing are more of the focus of this series on “who’s who in rearing?”  In future posts, I will discuss the overview of rearing and more details about the various rearing operations.

 

Why process control is valuable in rearing

Insect rearing is a process.  However large or small the rearing system is, the principles of process control can be made applicable.  As a result of controlling the rearing process, we have a more reliable, economic, and practical system.  The outcome of process control measures is almost certainly an improved product, which in this case is the insect population that we produce to meet our needs for research subjects, as the fundamental components of pest control systems, as food for other organisms, or whatever else our purpose is in rearing insects.

As processes, insect rearing systems are subject to the “rules” of process control.  These rules include the fact that data-driven processes can be subjected to analysis of where things may be going wrong and how potential problems can be prevented or minimized.  Therefore, statistical process control (SPC) can be a tremendous asset in helping us to organize our rearing systems.  As processes, insect rearing systems can best be improved and made predictable (and more quality-driven) by collection and analysis of data in our rearing process.

Fundamentals of Process Control: Inputs and Outputs

Fundamentals of Process Control: Inputs and Outputs

As an aid to explaining how we can visualize our rearing system in a model, I offer the above diagram that I adopted and modified from the Montgomery 1992 reference.

Eating Insects Part IV: Insect Farming: Alchemy vs. Science

In the past several blog pages that I posted, I discussed issues that are of broad interest rearing using insects as human food.  The following paragraph presents the major issues, and so far, I have discussed 1) through 3).  In this blog I will treat item 4).

Throughout this page, I am using the expression IHFE to name the Insects as Human Food Enthusiasts.

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?

Farming vs. rearing insects: I am making a distinction here between farming and rearing, where I consider farming a lower input process of insect production than rearing (which I consider more input intensive and more rigorously managed than insect farming).  This is my own distinction, which I think will be useful in the overview that I am trying to establish.  We already use what I would consider a hybrid between farming and rearing in production of silkworms fed mulberry leaves, crickets fed various mixtures of grains and supplementary materials such as vegetables and scraps from food processing systems.  Conventional production of meal worms is based on supplying grains and some vegetable materials such as potatoes and carrots as supplements to the grains and sources of moisture.  In each of these cases, millions of insects are handled in the production facilities.

In the case of silkworms, the major input is fresh mulberry leaves, and through the 5000 years of silkworm cultivation many improvements have been made in selection of optimal mulberry trees as well as leaf harvesting and presentation processes.  The considerable expense of maintaining orchards of prime mulberry and the labor in the silkworm farms though somewhat costly are rewarded by the very high price that quality silk brings to the producers.  The cultural implications of silk production is a remarkable story unto itself, but for our purposes, the silkworm model serves as an excellent example of getting a large scale biomass of insects from a fairly simple input.

For crickets, the use as food for other organisms drives the production system, and the question of cost/benefit is clearly understood when we realize that crickets are used by people who are willing to pay very high prices for crickets to feed their pets or for use in zoos and conservation programs.  I have indicated in my text (Cohen 2015) that cricket protein at current market prices is more expensive the protein available from the finest cuts of beef.  When we think about the cost of crickets from local pet stores being upwards of 10 cents per cricket, our incredulity is explained by realization that pet owners may pay 50 to 100 dollars for a pet lizard (some specially bred leopard geckos can be sold for upwards of $1000!)  So pet owners don’t flinch at paying 10 cents per cricket to keep their lizards (or tarantulas) happy.  However, if crickets are going to be used as human food at a scale that truly meets problems of human population growth and world hunger, then 10 cents per cricket would not be reasonable.  Taking for example, a 0.1 to 0.2 gram cricket and an estimated protein content of 10% of the cricket’s biomass, it would take 100 crickets to provide 1 g of protein, and given the FAO/WHO standard of 50 g of protein as a basic human adult requirement, it would take between 2,500 to 5,000 crickets to meet the daily requirements of a human adult male.  At 10 cents per cricket (admittedly a high price of retail crickets), it would take $250 to $500 per day to supply human protein needs from these crickets.  If the crickets’ cost were brought down to 1 cent per cricket, the cost of meeting the human protein needs would be 25-50 dollars a day (way more than we would expect people from emerging nations to be able to pay.  I realize that humans would not be expected to subsist on crickets alone.  The diets of insect-eating people would contain vegetables, other sources of meat, etc.  But the extreme example that I offer is based on the assumption that we are striving to make insects a significant contribution to the nutritional needs of our growing world population.  So how much insect protein would be considered a significant insect protein contribution?  If it were only 10% of the protein needs, then at the rate of 1 cent per cricket, it would require $2.50 to $5.00 per day to meet that need.

Clearly, all this means that the price of cricket production MUST come down to something more like 0.1 cent per cricket.  This means that other ways of cricket farming must be developed, and this is where the promises of the insects as human food enthusiasts (IHFE) need to do some deep thinking (and I think lots more research).  The standard argument that I have been hearing from the insects as human food advocates is that we can use really inexpensive foods for the crickets (or other insects to be produced for human food).  The IHFE folks argue that we can use waste streams such as food wastes and crop residues can be used to produce crickets.  This topic is covered elegantly in the paper in this paper: Lundy ME, Parrella MP (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 ).  These authors showed that there is nothing magical about crickets in terms of ability to convert low quality organic materials into nutrient-rich human food.

This is where I offer the concept of ALCHEMY vs. SCIENCE.  My wife, Jackie,  suggested this metaphor when I was explaining to her what I felt that IHFE people were expecting.  The practitioners of alchemy sought to convert the baser metals such as lead into gold.  The idea is intriguing that a wizard could use some kind of magic to make a cheap, common substance into a precious metal.  Of course we know today that this is not possible: our science teaches us why this kind of expectation is unrealistic, just as the laws of thermodynamics teach us that perpetual motion machines are fancy.  Yet, today, we still hope to get something for nothing or to get a lot of output from little input.

This is what I suggest that we are doing when we pursue conversion of low quality materials into nutritious insect biomass.

Besides the cricket systems, many IHFE supporters are enthusiastic about soldier flies, advocating that we can use poultry manure to rear high quality, high nutrition food (soldier flies) from the wastes that are abundant in poultry production systems.  I hope that I am clear about this: I am very supportive of recycling and systems of waste management that are efficient.  It would be useful to devise farming (or rearing) systems that allow us to use insects to help clean up wastes and at the same time can be used as foods for livestock.  The concept of using waste products as fertilizer is certainly in this line of thinking.  The use of Candida utilis (known as torula yeast) for conversion of wood pulp products that were wastes from the paper industry to a palatable and nutritious yeast product is well-documented as are other fermentation or bio-manufacturing procedures.  Use of algae to convert raw materials to nutritious food or biofuel has been accomplished with a fair degree of success.

So I am not saying that insects cannot be used in well-designed systems to improve waste remediation or other low input and sustainable strategies.  But my seeming iconoclasm is in response to the many claims that I keep reading and hearing about the magic bullet that insects will be to solve world hunger problems.

My major point about this is that there are sizeable gaps in our knowledge of insect husbandry that must be filled before we have any hope of making progress towards the scale of insect production that IHFE people are missing.  Filling that gap is the purpose of this website and the program that it represents.

 

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.

Insects as Human Food: Realistic Goal or Irrational Exuberance?*

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

The prospects of using insects as human food to meet future needs of a growing world population has become a topic of lively discussion.  For example, van Huis (2013) and van Huis et al. (2013) provide arguments about the benefits of what has come to be called “entomophagy” or what I call “entomophagy by humans” in light of my experiences with the many instances when entomophagous animals other than humans are discussed and studied.  And, in fact, in the mix of proposed uses of insects as livestock feed and as human food has stimulated considerable discussion and some research.  I have reviewed some of the papers on insects as human food in the 2nd edition of my diet book, but I did not cite an important and very thoughtful paper by Lundy and Parrella (2015) on the ability of crickets (Acheta domesticus) to capture protein from various diets, including waste streams.

Spoiler Alert: I approach this subject with skepticism. I think that the excitement about really meeting the needs of the growing human population with insects as a significant source of food (or protein, as it is popular to say is somewhat irrational—at least based on our current state of knowledge.

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?

I will be spreading my discussion over several blog posts on this site.  I realize that my answers to the above questions may be discouraging to insects-as-human-food enthusiasts, but I hope that the critical thinking that I am offering will stimulate thought and perhaps help the entomophagy enthusiasts be more prepared to succeed in their enterprise by having a realistic understanding of possible problems.

Cricket stir fry at BugFest 2014 in Raleigh, NC

Cricket stir fry at BugFest 2014 in Raleigh, NC

 

So in answer to the first question about whether or not people will accept insects as food, I see no question about this.  First, people have been eating insects in various cultures worldwide, using locally abundant insects with a great variety of preparation techniques.  Second, there is an increasing effort to render insect nutrients (especially insect proteins) into processed materials such as meal worm meal, cricket flour, and so on.  The processing can concentrate and possibly improve the food quality and simultaneously disguise the insect components.  So a meal worm bread that contains flour made from drying and grinding meal worms can go unnoticed in a person’s meal.

The enthusiasm for insect-eating can be seen at the annual Bug Fest in Raleigh, North Carolina where hundreds of people line up to get dishes prepared by local restaurants where the chefs have incorporated insects into savory dishes.  The video above shows some of this, and the cricket stir fry photo help make this point.  People can learn to eat insects just as they have other arthropods such as shrimp, crabs, lobsters, and crayfish.

 

*I have borrowed the term from Alan Greenspan, chairman of the Fed, and a term which Greenspan is said to have derived from Yale Professor, Robert Schiller (https://en.wikipedia.org/wiki/Irrational_exuberance).

Cohen, A. C. 2015.  Insect Diets: Science and Technology.  2nd Edition.  CRC Press.  Boca Raton, FL.

van Huis A. Potential of insects as food and feed in assuring food security. Annual Review of Entomology 2013; 58: 563–583. doi: 10.1146/annurev-ento-120811-153704 PMID: 23020616

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.

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

 

 

Anticipating and Treating Problems in Rearing Systems by Using Statistical Process Control: Getting Started

Insect rearing is a process.  The desired outcomes in rearing are to have insects that are healthy, representative of their species, readily available, useful for various programs (research, crop protection, conservation, as food for other organisms, etc.)  Being a process, insect rearing can be made more useful by application of process control, specifically statistical process control (SPC).  This concept was realized by a few pioneering authorities in insect mass rearing (including Boller et al. 1981 and Calkins et al. 1994: it should be noted that D. Chambers , T. Ashley, and E. F. Boller were suggesting the application of statistical quality control and SPC back in the 1970s, and a few facilities had adopted their suggestions.)

R. T. Staten and A. C. Cohen checking for problems in USDA, APHIS colony of big-eyed bugs in mass-rearing facility for predators

R. T. Staten and A. C. Cohen checking for problems in USDA, APHIS colony of big-eyed bugs in mass-rearing facility for predators

 

Green lacewing larva eating Cohen diet, feeding through a Parafilm membrane

Green lacewing larva eating Cohen diet, feeding through a Parafilm membrane

 

Getting Started in SPC:

A good first move in developing a process control system is to determine WHAT we are trying to control or what the problems may be = the causes of error or variability that have crept into our system.  A nearly universal tool or model of decision-making about which processes contribute the most to the benefit or the harm of our system is the Pareto analysis.  So, for example, when we were trying to mass rear predators such as big-eyed bugs (upper left figure with R. T. Staten and A. C. Cohen in the Phoenix USDA, APHIS lab in 1995 or the lacewing rearing as in the upper right image), we would try to reduce mortality in our system.  With careful observation by the rearing specialists, we decided that in one rearing unit (one rack) in our system we had the following causes of mortality or loss:

 

Pareto Plot of Mortality in Predators

In this case, we found that 22 deaths could be attributed to mold in the diet, 16 deaths from diet drying out, and cannibalism, poor stretching of the Parafilm membrane preventing the proper feeding seen in the upper right diagram, problems with molting, and escapes accounting for other loses.  In 8 containers, the causes of failure were not determined, possibly unseen pathogens or genetic defects.

The point here is that once we had collected data on the most likely causes of loss and the relative frequency of these causes, we could launch an effort to correct the problems, and clearly dealing with contaminants would be the most fruitful in improving our rearing outcomes (since nearly half the loses came from contamination.  This data-driven conclusion was based on the Pareto analysis, which is a simple tool that helps to shape decision-making about rearing system improvements.

This simple example tells us these things (take home messages): 1) collecting data is where to start, 2) using the expertise that is available is helpful in deciding what data to collect and how to interpret (e.g. how do we know how to recognize mold or desiccated insects?), 3) analysis of the data with graphic techniques can be very useful.

In a soon to be posted blog, we will cover some approaches taken to improve the problem with straggling in the Forest Service gypsy moth colony at Hamden, CT back in the late 1980’s (see ODell 1992 below).  It’s an excellent example of problem-solving approaches.

 

Boller, E. F., B. I. Katsoyannos, U. Remund, and D. L. Chambers.  1981.  Measuring, monitoring, and improving the quality of mass-reared Mediterranean fruit flies, Ceratitis capitata Wied. 1.  The RAPID quality control system for early warning.  Z. angew. Entomol.  92: 67-83.

Calkins, C. O., K. Bloem, S. Bloem, and D. L. Chambers.  1994.  Advances in measuring quality and assuring good field performance in mass reared fruit flies.  Pp. 85-96.  In C. O. Calkins, w. Klassen, P. Liedo [eds.], Fruit flies and the sterile insect technique.  CRC Press.  Boca Raton, Florida.  U.S.A.

ODell, T. M.  1992.  Straggling in gypsy moth production strains: a problem analysis for developing research priorities, pp. 325-350.  In T. A. Anderson and N. C. Leppla [eds.], Advances in insect rearing for research and pest management.  Westview, Boulder, CO.

 

 

Variability, Error, and Process Control in Rearing Systems

Thermal image of 3 hornworm containers

Thermal image of 3 hornworm containers

All processes, regardless of their purpose, are subject to variability or error.  Insect rearing, as a process, is subject to variability, and that variability is often the basis to failures in our systems.  We will cover in other blog posts and discussions on this site more of the details of the importance of variability (error) in rearing systems, and we will suggest ways to deal with it to ameliorate some of the error-caused problems.  For now, we will use an example of thermal variability in rearing systems.

 

These images were captured in my rearing room where I am testing some innovations in diets for tobacco hornworms (Manduca sexta).  The first figure is a thermal image of 3 rearing cages that contain diets that were poured into 8-cell plastic rearing trays.  All 3 cages are on the same shelf, side-by-side.  We opened each container and captured the thermal profile of each.

 

Reading these thermal Images: each image includes a range of colors where (in these images) dark blue is the cooler temperatures, and yellow/white depict the higher temperatures.  Also, the scale at the right shows a key to the temperature scale, and in the upper left corner the temperature of the region within the circle is presented.  So in the top image, the edge of the center rearing container is circled, and the temperature is 26.7 o C.

Thermal Image of hornworm rearing container 1 (26.1 to 32.3 C)

Thermal Image of hornworm rearing container 1 (26.1 to 32.3 C)

Thermal Image of hornworm diet 3 (25.8 to 31.7 C)

Thermal Image of hornworm diet 2 (25.8 to 31.7 C)

Thermal Image of hornworm rearing container 2 (23.8 to 27.9 C)

Thermal Image of hornworm rearing container 3 (23.8 to 27.9 C)

First, let us establish that the cylinders in each of the containers are glass tubes used to hold eggs and release neonates to infest the diet.  Please note that the temperatures in each container follow a thermal gradient and are characterized by a 4 to 6 degree C range of temperature; and furthermore the diets are always cooler than the plastic sides of the diet tray.  In container 1, the diet’s surface temperature (where the insects are feeding) ranges from about 26 C to about 28 C.  This is quite different (in terms of temperature) from container 3 where diet in the lower right hand cell is about 25.3 degrees C.  Therefore, despite the fact that the insects are being held in the same types of containers on THE SAME SHELF in the rearing room, there is chronic (continuous) exposure to temperatures that are at least 1-2 degrees C different from one-another.  Knowing how important temperature is as a growth/metabolic determinant, it is clear that we have inadvertently imposed a temperature factor in the rates of growth–a factor that is going to cause an error that detracts from our interpretation of the diet evaluation!

Take home message: nearly every factor/component in our rearing systems has an inherent variability (error).  If we recognize these factors/sources of error and try to correct them, we will improve our rearing process (i.e. we will CONTROL it).

 

 

 

 

 

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