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UTILIZATION
OF USEFUL INSECTS AS FOOD SOURCE
Joseph
Allotey*1 and Sisai Mpuchane1
INTRODUCTION
There
has been an upsurge of interest in the use of insects as food. Recently,
at an international conference outside Africa, some edible caterpillars,
two types of canned caterpillars (in brine and in tomato paste)
and some plastic-packaged caterpillars, which were on display, generated
profound interest among the participants. There was expression of
elation, wonder, and curiosity on the faces of those participants
who consumed this important food product. A number of questions
were raised by the participants on edible insects. The caterpillars
were from Africa. The canned caterpillars were left with the organizers
of the conference who expressed their desire to inform their colleagues
about edible insects. Suffice to say, edible insects are and have
been traditionally and nutritionally important food for Africans.
They have been utilized as food in Africa, Asia, Australia and Latin
America for many years.
Insects
are regarded as the most successful group within the animal kingdom.
Over 80% of all living animals are insects. About one million species
of insects are known and over 7,000 new species are described every
year. Prominent reasons for their success are: ability to live in
and adapt to diverse habitats, high reproductive capacity, ability
to consume different kinds and qualities of food, and the ability
to escape quickly from their enemies [1].
Insects
play both negative and positive roles in the lives of humans. They
may destroy our crops as pests and transmit diseases to man as vectors.
However, not all insects are pests or vectors. The majority are
harmless and many are beneficial. A number of insects including
winged termites, grasshoppers, locusts, crickets, beetle grubs,
ants and caterpillars are edible.
Insects are high in protein, energy and various vitamins and minerals.
Food insects are eaten raw or roasted or are dried and added to
other foods. The mature larvae of the palm weevil, Rhynchophorus
species have been utilized as food source by people of the tropical
areas of Africa, Asia and Neotropics for centuries. Different ethnic
groups in Africa may consume insects based on preference and abundance
of particular insect species. The natives of southern Africa have
used a number of insects as food, including caterpillars, locusts/grasshoppers,
ants, termites and beetles [2, 3]. The larval stages, or caterpillars
of various emperor moth species (Saturniidae) are some of the best
known and are presently the most commonly utilized food insects
in southern Africa. For example, in Botswana, the edible caterpillar,
commonly known, as "phane" is the larval stage of the
emperor moth, Imbrasia belina. The larvae are collected
when they reach the 4th or 5th instar. These
are degutted, cooked in brine and dried to make an edible product,
which is a delicacy in many parts of southern Africa.
Occasionally,
the caterpillar is also used as a protein supplement in poultry
and cattle feeds. It contains 38+ % protein, 16+ % fat, ca 13+ %
carbohydrate and some chitin [4, 5, 6, 7]. The lipids are made up
of C16 and C18 saturated fatty acids and C18:1 and C18:2 unsaturated
fatty acids [8]. It has been estimated that 100 grams of dry phane
may provide 76% of an average human daily protein requirements and
100% of the daily requirements of vital vitamins and minerals and
that it compares favorably with meat and fish in terms of protein,
fat, vitamins and calorific content [9]. It has been recommended
as a supplement for high cereal diets and infant foods [4]. Evidence
now shows that it is also being exported even to far away countries
such as the USA and Korea for other purposes [10]. Phane is available
as a street food, being sold by vendors, as canned food and now
in restaurants. It is therefore important that consumers be supplied
with wholesome caterpillars. The technology for preserving this
delicacy was developed generations ago. Unfortunately, to date we
still are concerned about post harvest problems that are associated
with this edible caterpillar that result in its short shelf life.
The proper processing and storage of the worms become therefore
important not only for the extension of the shelf life but also
for providing consumers with sound caterpillars. That this caterpillar
is of economic importance is shown by its depiction on Botswana's
new 5 Pula coin. The choice of mophane worm (phane) is especially
appropriate since it is an important source of protein throughout
Botswana. The image of the adult stage of this emperor moth, I.
belina is on postage stamp in Botswana.
Certainly
this edible caterpillar has come along way regarding its acceptance
nationally, regionally and perhaps internationally. However, entomophagy
or the eating of insects is decidedly conditioned by cultural biases.
Many areas of the world have and still derive part of their protein
from insect sources. Why then have we not taken advantage of the
presence of many and diverse species of insects on the continent
by promoting their incorporation into diets? Considering the chronic
or seasonal shortage of vertebrate protein reserves in sub-Saharan
Africa, utilization of insects, as alternative food source on a
wide scale should be encouraged. Nutrients useful in the maintenance
of human health may be obtained by direct consumption of insects.
Food supplies in many countries in Africa are inadequate in quantity
and quality, contributing to the widespread malnutrition on the
continent [11].
Since
insects are so abundant and contain many useful nutrients, including
proteins and calories, they may help in solving the problem of malnutrition
in Africa. Malnutrition continues to kill many children, act as
a catalyst in various childhood diseases, exacerbate rates of illiteracy,
and unemployment and impede overall socio-economic progress in Kenya
[12]. Several ways to use phane as a high protein food component
have been explored [4]. The most promising of these was the addition
of phane to weaning food. Sorghum was mixed with phane at a ratio
of 80:20 to give a protein content of about 18%, and with Bambara
nuts and Phane at 40:40:20 (sorghum: bambara nuts: phane) to give
a protein content of about 20%. These mixtures were reported to
be the best mixtures suited for people that are 10 years and older.
The
microbial load of contaminants in phane can be effectively reduced
by vinegar treatment during processing, and in post-processing stage.
In the case of weaning food, microbial quality becomes especially
important. The results of a study that sought to test the hypothesis
that the addition of phane to maize can improve the pasting characteristics
of the maize/phane blends have been reported [13]. In general the
addition of phane resulted in a decrease in pasting characteristics
for blends containing either unfermented or fermented maize, with
the reduction becoming more pronounced with increasing levels of
phane [13]. The presence and concentration of phane and/or fermentation
is crucial in determining the eating consistency of the product.
It is envisaged that given the necessary inputs and support in terms
of research funding, scientists could bring to full realization,
hope of increasing the production of edible insects as well as tackling
health related issues.
There
are more than 400 known species of edible insects. As the population
of the world grows, greater demands are being placed on food production.
Since insects are so abundant and since they contain many useful
nutrients [14], including protein, it seems reasonable to eat them
[15]. The present food situation in Africa makes it obligatory to
search for new food alternatives that enrich the basic diet and
fit within traditional African food habits. Studies in the traditional
lifestyles of southern Africa suggest that insects may have supplied
a substantial amount of 'animal' protein in the diet [2,3]. The
encouragement of entomophagy in many rural societies, particularly
those with a history of insect use, may help diversify peoples'
diet. However, there are concerns with regard to the safety aspect
of edible insects. Improving food safety is an essential element
of improving food security, which exists when populations have access
to sufficient and healthy food. Good food is basic to good health
and food safety is receiving increased attention due to several
worldwide trends affecting food system. Standards such as the joint
FAO/WHO Codex Alimentarius Commission (Codex, in short) was established
in 1962 to protect the health of consumers and at the same time
to ensure fair practices in food trade by promoting the harmonization
of food standards applied by various members of the Codex. According
to United Nations, a household is food secure when it has access
to adequate food for a healthy life for its members (adequate in
terms of quality, quantity, safety and acceptability) and when it
is not under risk of losing such access.
The
traditional methods of preparation of edible insects can be improved
to provide a high quality and acceptable product. It is important
to determine the sanitary quality of edible insects and sources
of contamination. For example during processing, phane comes into
contact with soil and consequently becomes recontaminated with microorganisms
that cause spoilage during drying and storage. In storage, phane
may lose quality characterized by increased infection by fungi.
During fungal infestation, there is a loss of dry matter through
utilization of proteins and lipids leading to reduction in nutritional
value. In food spoilage, fungi rank second to insects as a cause
of deterioration and loss. The species of Chaetomium 13.8%,
Aspergillus 12.4%, Fusarium 5.5%, and Mucor
racemosus 4.1% were the most prevalent in the intestinal contents
of phane, whereas Aspergillus 42.1%, Penicillium
33.9%, and Mucorales 5.7% were present in laboratory stored
phane. The important mycotoxigenic fungi A. flavus, A.
parasiticus, A. ochraceus, P. aurantiogriseum, P. citrinum
and P. verrucosum were isolated from the laboratory-stored
phane. The genera isolated from both intestinal contents and the
stored phane were Alternaria, Aspergillus, Chaetomium, Drechslera,
Fusarium, Mucor, Phoma and Penicillium suggesting
recontamination during drying and storage [16].
Poor
sanitation is an important factor in the contamination of dried
phane. Therefore, educating the harvesters/processors on the proper
disposing of intestinal contents would reduce contamination during
drying. For safe storage of phane, methods recommended for other
products should apply [17,18]. To maintain quality, phane should
be dried quickly and evenly after harvesting and processing and
kept in cool and dry storage area. Food contamination by biological
agents of disease is now recognized as a major public health problem
all over the world. HACCP (Hazard Analysis Critical Control Point)
system is a system that identifies, evaluates and controls hazards
that are significant for food safety. It has been used to ensure
quality, food safety and suitability of consumption of food products
from primary production to final human consumption. HACCP, in some
form is now the food management method of choice for most countries
through out the world and pressure for its adoption is growing [19].
Certain
food hazards are closely linked with sanitation, water supply, food
preparation, and marketing of food. Hazard analysis of phane should
consist of observing harvesting, food processing (degutting, boiling),
hot charcoaling, cooling, drying, bagging, transportation, storage,
point of sale and consumption, to identify sources and mode of contamination.
Currently,
some of the preventive measures that need to be observed by traditional
processors to avoid contamination are:
Degutting
stage
i. Ensure that holes have been dug for disposal of the gut contents
of phane during degutting.
ii. Holes must be covered immediately after degutting.
Drying
stage
i. Ensure that infested bags (hessian and polypropylene) are disinfested
through boiling for at least 30 minutes and drying in the sun for
at least two hours before usage in the field.
Storage
i. Ensure that bags are highly clean and without infestation before
putting phane into them.
ii. Ensure that bags are immediately tied with rope and seams sewed
up, covered with polythene material and placed on a raised platform
to prevent cross- infestation from the surrounding, and moisture
from the ground penetrating the bags.
Hazard
analysis at vending sites is necessary to assess risks leading to
microbial growth and potential food borne illness. Consumers need
to be assured that foods appearing on their markets, where ever
they come from are safe. Food insects should be well packaged. Packaging
for aesthetic presentations for consumer appeal is a marketing strategy
that goes hand in hand with food processing. Co-operative efforts
at training are required to deal effectively with infestation/infection
problems in the manufacture of consumer products. Food insects are
highly valued in Africa and in South Africa, the Pedi preferred
the caterpillars of I. belina to beef [3].
Not
all insect species are safe to eat. Some insects are distasteful
and some people can develop allergies to insect materials. There
are some insects that secrete toxins, produce toxic metabolites
or sequester toxic chemicals from food plants. More attention should
be directed toward assessing the risk factors in edible insects.
In general not many people have accepted the concept of entomophagy,
though some insects are equally or perhaps more palatable and nutritious
than other related Arthropod groups (eg Crustacea) such
as shrimps, crayfish, and crabs. The growing awareness and the interest
people have shown in utilizing insects as a valuable protein source
cannot be overlooked. If carefully regulated, cultivating food insects
for protein should be less environmentally damaging than other animals.
Insect farming is compatible with low-input, sustainable agriculture
and most insects have a high good conversion efficiency compared
with conventional meat animals. The unpredictability of many wild
populations of food insects needs to be averted by development of
culture techniques especially as over-harvesting from the wild could
threaten the viability of some insect populations.
Research projects on edible insects should be:
| i. |
to obtain background information on the existing processing
technologies of selected edible insects and to identify the
spoilage agents associated with these insects, and estimate
the loss during processing and storage. |
| ii. |
to study
the effects of microbial and insect infestation on the chemical
composition and nutritional value of the selected edible insects. |
| iii. |
to study
the effect of packaging and packaging materials and their interaction
with insects/molds/processed food insect during storage; and
to evolve effective control measures. |
| iv. |
to improve
the technology presently available and developing training programs
in the production of new insect foods. |
| v. |
to study
the probability of insect farming as a means of increasing production. |
Multi-dimensional
expertise of researchers (entomologists, food microbiologists, biochemists,
mycologists, food scientists/technologists, ecologists, and social
scientists) should be involved, to obtain a holistic picture in
relation to factors surrounding edible insect production. The environmental
dimension will look at the impact of commercialization, the role
of women, men, and children in this regard, including type of conservation
methods employed. Training programs will be useful in disseminating
findings.
It
is easy to love insects for their beauty and not as food. Maybe
before we look at entomophagy with disdain, it is possible that
one may inadvertently have consumed insects milled along with infested
grain or flour used for baking bread. We should not forget also
that honey, which is an important human food, is an insect product.
Finally,the
authors would like to close this column by thanking the Editor-in-Chief
and founder, Hon. Prof. Ruth Oniang'o, for her vision, dynamism
and foresight, and all the editorial staff and editorial board members
for creating and fostering this multi-disciplinary international
research journal, the African Journal of Food, Agriculture, Nutrition
and Development (AJFAND), which is widely accepted worldwide.
Disclaimer:
The authors
are not responsible for gastric distress, allergic reactions, feeling
of repulsion, or other problems resulting from ingestion of food
insects.
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