BASIC TECHNIQUES FOR MUSHROOM CULTIVATION
Table of Contents
1.0 INTRODUCTION ......................................................................................................................1
A. Mushrooms.................................................................................................................................1
B. Mushroom Biology......................................................................................................................1
I. Classification ...........................................................................................................................1
II. Occurence ...............................................................................................................................1
III. Growth ................................................................................................................................1
IV. The Structure of Mushrooms..............................................................................................1
V. Life cycle of a mushroom/Fungus...........................................................................................2
VI. Ecological types...................................................................................................................2
VII. Species diversity of mushrooms .........................................................................................2
C. Mushroom hunting/Mushrooming.............................................................................................2
D. Identification of Edible and poisonous mushrooms...................................................................2
E. Mushroom poisoning..................................................................................................................3
I. Reactions Due To Consumption of Poisonous Mushrooms....................................................3
II. Management of mushroom poisoning ...................................................................................3
III. Guidelines on avoidance of mushroom poisoning (Gour, 2010)........................................4
F. World mushroom organizations and movements......................................................................4
I. International Society for Edible mushrooms-.........................................................................4
II. International movement for Medicinal mushrooms..............................................................4
III. International movement for wild mushrooms ...................................................................4
2.0 MUSHROOM CULTIVATION TECHNOLGY........................................................................5
A. Importance of mushroom cultivation.........................................................................................5
G. Stages in mushroom growing .....................................................................................................6
I. Stage 1: Selection of mushroom type to be grown ................................................................6
II. Stage 2: Production of starter culture/Fruiting culture..........................................................6BASIC TECHNIQUES FOR MUSHROOM CULTIVATION1.0 INTRODUCTION
A. Mushrooms
Mushrooms are fruiting bodies/reproductive structures of large fungi/fleshy fungi/macro
fungi. Majority are edible while other is not poisonous and thus not edible
B. Mushroom Biology
I. Classification
Fungi belong to the Kingdom Mycetae. They mainly belong to the order Agaricales of class
Basidiomycetes. Some however belong to the class Ascomycetes (e.g. Morels).
II. Occurence
Mushrooms have different sizes, shapes and colour. Mushroom can be emergent or
underground. A fungus spends most of its time underground or in decaying wood and these
surroundings are not ideal for the dispersal of spores. A fungus needs to make large numbers
of spores and it needs to disperse them efficiently to increase the probability that the spores
will find new sources of nutrients to exploit. The mushroom serves this purpose well by
rising above the substrate to get its spore producing apparatus into the air.
III. Growth
Mushroom-producing fungi perform valuable roles in ecosystems. They are decomposers,
responsible for recycling dead organic matter -- notably wood -- back into molecular form to
be used over and over again by other organisms as nutrients. Most are beneficial, but a few
are parasitic on living trees.
Mushroom formation is triggered by some combination of environmental conditions. Usually
a cool spell accompanied by adequate moisture (rain) is needed.
Mushrooms begin as Primordia, which are little bumps of cells that appear at the place from
which a mushroom is to develop. If the moisture is sufficient and the humidity high enough,
the promordia go on to produce fully developed mushrooms.
IV. The Structure of Mushrooms
The basic parts of a mushroom (technically known as a basidiocarp) are the stipe (stem), the
pileus (cap) and either lamellae (gills) or tubes which are covered (or lined in the case of
tubes) with reproductive cells call basidia from which spores are produced. The spores are
usually actively ejected from the gill or tube surface to float down and out of the cap, to
where even the slightest breeze is enough to transport them far and wide.V.
Life cycle of a mushroom/Fungus
A fungus has two main phases of growth: Vegetative and reproductive phases (sexual or
asexual). Vegetative stage is the stage of expansive mycelia development colonizing
substrates while the reproductive phase is the stage at which mushrooms (fruiting
bodies/reproductive structures) are produced.
VI.
Ecological types
They are classified into three (3) groups:
Parasites
Symbiotic (mycorrhizal)
Saprophytic
VII.
Species diversity of mushrooms
By 1990, the number of known species of was 70,000. Out of these 2,000 of these species
from 31 genera are edible. Of the 2,000, 100 species are experimentally grown and 50 are
economically cultivated, 30 species are commercially cultivated. Six (6) of the commercial
species have reached industrial level. 1,800 species are medicinal.
The number of poisonous mushrooms is only 10% of the known species. 30 species of the
poisonous species are lethal. (Miles and Chang, 1997)
C. Mushroom hunting/Mushrooming
This refers to the process of identification and collection of mushrooms
D. Identification of Edible and poisonous mushroomsV.
Life cycle of a mushroom/Fungus
A fungus has two main phases of growth: Vegetative and reproductive phases (sexual or
asexual). Vegetative stage is the stage of expansive mycelia development colonizing
substrates while the reproductive phase is the stage at which mushrooms (fruiting
bodies/reproductive structures) are produced.
VI.
Ecological types
They are classified into three (3) groups:
Parasites
Symbiotic (mycorrhizal)
Saprophytic
VII.
Species diversity of mushrooms
By 1990, the number of known species of was 70,000. Out of these 2,000 of these species
from 31 genera are edible. Of the 2,000, 100 species are experimentally grown and 50 are
economically cultivated, 30 species are commercially cultivated. Six (6) of the commercial
species have reached industrial level. 1,800 species are medicinal.
The number of poisonous mushrooms is only 10% of the known species. 30 species of the
poisonous species are lethal. (Miles and Chang, 1997)
C. Mushroom hunting/Mushrooming
This refers to the process of identification and collection of mushrooms
D. Identification of Edible and poisonous mushrooms Seek medical help with a sample of the mushroom that caused the poisoning for
purposes of administration of specific-fungus-antidote
III.
Guidelines on avoidance of mushroom poisoning (Gour, 2010)
Do not eat mushroom because it is beautiful or has pleasant smell. Amanita muscaria
is the most beautiful but the most poisonous
Never eat an uncooked mushroom unless you are sure that it is edible
Avoid gathering and eating wild mushrooms at button stage because button stage
species cannot be identified easily.
Do not eat over mature, insect infested or wilting wild mushrooms.
Avoid mushrooms oozing a white milky juice when cut
When eating an edible species of mushrooms, for the first time, eat only in small
amounts.
Do not eat mushrooms partially eaten by animals or insects because they may not be
safe for human consumption
F. World mushroom organizations and movements
I.
International Society for Edible mushroomsIt was created in 1950 and it is concerned with mushroom production.
This society evolved into International Commission on Mushroom Science and later into
International Society for Mushroom Science (ISMS) which is mainly concerned with
production of Agaricus bisporus
II.
International movement for Medicinal mushrooms
It is mainly concerned with medicinal mushroom products (mushroom derivatives)
III.
International movement for wild mushrooms
It is concerned production of wild mycorrhizal mushroom2.0 MUSHROOM CULTIVATION TECHNOLGY
Mushroom cultivation is a farming activity that can be simple and it may involve high
technology. It is an art and a science because it requires practical experience and at the same
time it is developed through scientific research.
A. Importance of mushroom cultivation
They are highly nutritious food.
A good source of high quality protein. They contain 20% – 35% protein on dry weight
basis(Gour, 2010)
Contain good amount of Vitamin and Vitamin B complex
They are a source of potassium, phosphorous and Sodium. They have a very high
K:Na ratio and thus suitable for patients with high blood pressure
Have low calories, little fats and sugars and without starch and cholesterol.
Extracts from mushrooms have medicinal properties.
Extracts have antifungal and antibacterial properties
They are used in production of pharmaceuticals for treating various diseases.Genera
with medicinal species include Lentinus, Coriolus, Ganoderma amd Schizophylum.
They have high amount of retene known to fight cancer
They can induce the formation of interferons good protecting the body against viral
infections
They have the ability to lower cholesterol levels
Mushrooms are useful in recycling of agricultural waste materials which would
otherwise cause environmental pollution.
It provides an avenue for increasing food supply
It is a source of foreign exchange
Mushroom growing promotes women economic development without sacrificing their
household responsibilities.
Provides employment for youth and women Spent compost substrates (by-products of mushroom growing) an be used as fertilizer
or animal feed.
G. Stages in mushroom growing
I.
Stage 1: Selection of mushroom type to be grown
You cannot grow mushroom without knowing what you are growing. In the choice of
mushroom to be grown, one considers the following:
Market- the chosen mushroom type must be acceptable locally and internationally for food or
medicinal purposes. Always ask yourself who your customer will be.
Availability of suitable substrate- e.g. distance from the source to the farm or the cost that
you will incur in acquiring the substrate
Environmental conditions for growth- the conditions for growth must be met without
incurring excessive cost of production or high technology. For instance, mushrooms which
require fermentation/composting of substrates may not be suitable for beginners or small
scale mushroom farmers. Oyster mushroom (Pleurotus) is always the simplest and the
cheapest mushroom to grow and manage.
II.
Stage 2: Production of starter culture/Fruiting culture
Starter culture is the first line mycelium that is propagated as “seed” strain. The starter culture
must have the genetic qualities of good yield, flavour, texture and fruiting time (mature
faster).
Sources of starter culture
Tissue culture
Spore culture
Sub-cultures from research laboratories
Cultures from other sources e.g. from existing spawn
Starter culture media
Mushroom mycelia grow on a variety of culture media on different agar formulae which
could be natural of synthetic. The following media are commonly used for culturing fungi.
PDA (Potato Dextrose Agar)
WEA (Wheat Extract Agar)
MEA (Malt Extract Agar)Preparation of Potato Dextrose Agar (PDA)- Culture Medium
PDA is the simplest and the most popular medium for growing mushroom mycelia. PDA
powder can be bought from any shop that supplies school laboratory equipment and
chemicals.
Requirements
PDA
Distilled water
Glass rod
1000ml beaker
Measuring cylinder
Source of heat
Autoclave/pressure cooker
Test tubes
Procedure
Measure 39g of PDA powder and pour into 1000ml beaker with 500ml distilled water
Heat the mixture while you stir until it completely dissolves
Increase the volume of the mixture to 1000ml by adding distilled water
Measure 5mls of the liquid mixture into test tubes and plug with cotton wool
Sterilize the media in a pressure cooker or autoclave for 15-20 minutes at 1210C
Place them in slanting positions before they solidify and wait for the to cool and solidify. The
agar slants provide large surface area for growth of mycelia.Preparation of Potato Dextrose Agar (PDA)- Culture Medium
PDA is the simplest and the most popular medium for growing mushroom mycelia. PDA
powder can be bought from any shop that supplies school laboratory equipment and
chemicals.
Requirements
PDA
Distilled water
Glass rod
1000ml beaker
Measuring cylinder
Source of heat
Autoclave/pressure cooker
Test tubes
Procedure
Measure 39g of PDA powder and pour into 1000ml beaker with 500ml distilled water
Heat the mixture while you stir until it completely dissolves
Increase the volume of the mixture to 1000ml by adding distilled water
Measure 5mls of the liquid mixture into test tubes and plug with cotton wool
Sterilize the media in a pressure cooker or autoclave for 15-20 minutes at 1210C
Place them in slanting positions before they solidify and wait for the to cool and solidify. The
agar slants provide large surface area for growth of mycelia.13. A “fuzzy” mycelium begins to grow in a few days to a week.
14. If molds are seen (Usually detected by their green, blue, black or other coloured
spores) or bacteria (usually creamy or otherwise coloured slimy material) the culture
should be discarded immediately. Preferably sterilized.
Spore culture procedure
This can be through – monospore or Multispore culture.
Multispore culture procedure
1. A newly opened mushroom fruit is cleaned and left flat on a filter paper in a Petri
plate with the gills downwards. The set up is then covered with a breaker. All the
glassware and filter paper should be sterile.
2. The gills of the mushrooms will discharge the spores into the filter paper within a day
or two.
3. The breaker and mushroom are removed and a sterilized lid in placed on the dish.
4. The filter paper with spore print is cut into stripes aseptically.
5. Such a stripe is placed in 10 ml of sterile water in a test tube.
6. The spore suspension is mixed with liquefied agar medium and poured into sterilized
Petri dishes or test tube before slanting.
7. The agar medium is allowed to solidify. In a few days, the fused mycelium will grow
on the surface of the medium. Another method can also be used for multispore:
8. Dip a sterilized needle into sterilized water.
9. touch the moistened tip of the needle to a spore suspension of spore print.
10. The mass of surface spores will stick on the needle tip.
11. This in then aseptically streaked directly on solidified agar medium either on slants or
in a Petri dish.
12. The spores will germinate to form mycelium.
Monospore/Single spore culture
1. A spore suspension is made as above.
2. The suspension is diluted in such a way as to give few number of spores.
3. (One) 1ml of diluted spore suspension is then placed onto sterilized solid agar
medium in a petri plate and shaken well to separate them.
4. Isolated spores will germinate in a few days.
5. Germinating spores can be seen on the inverted plates by transmitting light.
6. Mark the single germinating spores on the inverted plate by use of glass marking
pencil.
7. The portion with a single germinating spore is cut with a sterilized flat needle and
transplanted to new agar medium.
8. N/B All the operations above should be done aseptically in a laminar flow hood or
cabinet previously exposed to U.V light for 1 hoPreservation and storage of starter culture
Pure cultures of cultivated mushrooms are necessary to maintain vigour and productivity.
There are various methods preserving cultures.
1. Periodic transfer: stock culture is maintained by periodic sub-culturing in fresh
media. Monthly transfers into new agar tubes should be done to maintain their vigour.
It is advisable to change the culture after four subcultures since the culture loses
vigour with subsequent sub-culturing.
2. Refrigeration: Once the mycelium has fully covered the agar surfaces, the tubes
should be refrigerated at 40C.
3. Freeze drying/Lyophilization: it is the most effective method for long term
preservation. The spore or the starter culture are frozen and at the same time dried
using a Lyophilizer (under low pressure in a vacuum)
4. Cryogenic freezing: involves freezing with the aid of compounds that protect the
living cells against damage during freezing. The culture are sealed in ampules and
then stored in a freezer or liquid nitrogen.
5. Using mineral oil: Sterilized/autoclaved mineral oil is added to fully grown starter.
The oil depth should be up to a depth of 1cm above the slant. Culture and kept in the
oil for up to 3 years.
III.
Stage 3: Preparation of Mother Spawn/ planting spawn (“seed”)
A spawn is basically means mycelia of fungi used for propagation. In mushroom production,
spawn is the mushroom seed or the substrate into which a mushroom mycelium is developed.
Type of Spawn
-Liquid spawn
-Grain spawn
Spawn Production
Grains of wheat, barley, sorghum and millet are suitable media for spawn production.
Farmers should therefore, use whichever grain is cheaply available in their locality. All the
grains should be less than a year old and free of any other debris.
Methodology
1. Wash the grains thoroughly, removing the dead ones or those that float in water and
other debris.
2. Soak the grains in water overnight and wash them again the following day3. Boil the grains with an equal amount of water on weight basis for 20 -30 minutes. The
idea is to make them soft. Caution should be taken not to split the grains since this
might lead to loss of starch.
4. Take out the grains from water and spread them on a sloppy surface in order to drain
off excess water.
5. Mix the grains with Calcium carbonate and calcium sulphate at 2% each on wet
weight basis.
6. Fill the mixed grains loosely to 2/3 rd in spawn bottles ( about 500 – 600g of mixed
grain per bottle). Glucose bottles or 500 ml conical flasks or heat resistant polythene
bags can also be used as spawning containers. Plug the spawn bottles with cotton
wool.
7. Sterilize the spawn bottles with mixed grains for two consecutive days at 1210C for
one hour
8. Allow the spawn bottles and their contents to cool prior to inoculation.
9. Inoculate grains in each spawn bottle with 2 – 4 (depending on amount of grains in
spawn bottles) mycelia agar disks of 5 – 6 mm in diameter cut from the edge of
vigorously growing my mycelia culture of the mushroom species of choice. A cock
borer can be used to cut the mycelia agar discs.
10. Incubate the setup at 250C.The grains will be fully colonized within two to three
weeks and the spawn is ready for seeding the final substance.
11. If the spawn is not to be used immediately, it should be refrigerated at 40C. However,
prepared spawn should be stored for more than two months as this leads to loss of
vigour.
12. It is important to note that spawn production is a highly specialized activity, requiring
skills in media preparation, sterilization and aseptic transfer or inoculation techniques.
The facilities used in spawn production may also be expensive to most small – scale
farmers. Since the spawn quality has direct influence on the final yield, it is advisable
that farmers who cannot produce quality spawn should consider buying it from
commercial spawn producers.
Qualities of Good Spawn
Should be free from fungal and bacterial contaminants.
The spawning medium should be fully coated with the mycelium.
Should be easy to spread evenly on the final substrate
Should have a strong mushroom smell.
Should not be more than two months oldIV.
Stage 4: Preparation of substrate and spawning/planting
Wheat straw, barley straw, maize cobs, banana pseudo stems, water hyacinth, sawdust, hay
and many other agricultural wastes are suitable substances for pleaurotus production.
Farmers should therefore, choose the substrate that is cheaply available in their region so as
to reduce the cost of transportation.
Procedure
1. All the substance should be allowed to dry to a moisture content of about 12%.
Substrates with moulds should be avoided.
2. Cut the substrate into 2 – 3 cm pieces. This is ti increase the surface area and at the
same time ensures suitable compactness to allow for penetration of the mycelia. If
pieces are too large, mycelia find it difficult to cross between pieces, if too small, the
substrate will be too compact hence difficult for mycelia to spread.
3. Soak the chopped substrate in clean water for 12 hours, drain off excess water after
this. Soaking makes them soft to improve workability.
4. Pasteurize the substrates by dipping it in hot water at 90 – 1000C for one hour.
Transfer the sterilized substrates into the inoculation chamber. Other methods of
pasteurization include use of steam and of use chemicals.
5. Sterilize the supplement of choice (cotton seed cake, sunflower seed cake, gram flour,
wheat bran, fishmeal or a combination of them) by autoclaving at 1210C for 15
minutes. A pressure cooker may be used where an autoclave is not available. Take the
sterilize supplement into the inoculation chamber also.
6. Thoroughly mix the pasteurized substrate with the sterilized supplement at 5% for
grain flour, fish meat, cotton and sunflower seed cakes, and at 20% for wheat bran.
Various other combinations of the supplements may also be used.
7. Fill the mixture into clear polythene bags (30 x 45cm in size) with holes of 1cm
diameter and 5 – 6 cm apart all along the sides. During the filling, add grain spawn/
mushroom seed (at 3% wet weight basis) in two layers. Each bag will contain about 1
kg of dry substrate.
8. When the spawned bags are white and compact(three weeks) cut the polythene bags
on the sides and remove them. Care should be taken not to disturb the compact bed.
9. Once the bags are opened, increase the humidity to about 80 – 90% by spraying water
on the beds at least twice a day and hanging moist gunny bags at around the
mushroom house. You can use two thermometers, one dry and the other wet a chart of
coordinates to read the humidity. Care should be exercised not to confuse high
humidity with dampness, as the later will encourage diseases.
10. The sporocaps are expected to start appearing within three to four days. Harvesting
should be done just before the mushroom edges start curving upwards. Harvesting is
done by grasping the stalk and twisting and then pulling it out, cutting by use of a
knife is discouraged since it increases chances of infection.
11. Depending on the intended use of the mushroom produce, various treatments may be
taken to ensure that it does not go bad before reaching the consumer
H. Mushroom pests and diseases
Bacteria, other fungi, nematodes, mites and insects affect growing mushrooms.
All the pests and diseases can be avoided/minimized by observing proper hygiene.
V.
Control of bacterial pests/diseases
Proper Hygiene
Use chlorinated water as a routine spray. Dissolve 150ml of hypochlorite in 100l of
water used for spraying or watering.
VI.
Control of fungal diseases
Proper hygiene
Use of fungicides eg.use of Bavistin, Benomyl and Bravo. Chemicals are not
recommended for routine management.
Use of 2% formalin on exposed surfaces e.g. On polybag holes
VII.
Control of insect pests
Remove all spent compost away from the mushroom house
Use of insecticides especially pyrethrins3.0 HARVESTING AND POST HARVEST HANDLING
A. Harvesting of mushrooms
Button mushrooms are ideally handpicked. However, other mushrooms like Pleurotus are cut
with retractable knives or at the base. Only harvest the ones, which are mature and leave the
small ones.
I.
Preservation and Processing of mushrooms
Mushrooms are consumed fresh or preserved. Shelve life of fresh mushrooms vary from 1
day to 2 weeks depending on: structure and condition of the mushroom, relative humidity and
temperature of the environment and air movement over the mushroom in the package.
The shelf life can be extended by refrigeration at 1- 4 ⁰c and only suitable for short term
storage.
For long term storage, canning, pickling and drying processes are employed. These methods
are not suitable for all types of mushrooms because they modify the quality and taste of the
finished products.
VIII.
Canning:
This involves cleaning, blanching, sterilization, cooling, labelling and packing.
1. Clean the mushroom thoroughly and soak for 30minutes in water small amount of
ascorbic acid.
2. Rinse the mushrooms and blanch for 2 minutes
3. Place the blanched mushrooms in cans containing 2.5% Sodium chloride solution
(Dissolve 1.46g in 1L of water) and 0.5% citric acid
4. Seal the cans and sterilize in autoclave for 1 hour at 1210C
IX.
Pickling:
It similar to canning.
Special equipment:
2 pint jars, canning pot
Ingredients
1 pound oyster mushrooms 3.0 HARVESTING AND POST HARVEST HANDLING
A. Harvesting of mushrooms
Button mushrooms are ideally handpicked. However, other mushrooms like Pleurotus are cut
with retractable knives or at the base. Only harvest the ones, which are mature and leave the
small ones.
I.
Preservation and Processing of mushrooms
Mushrooms are consumed fresh or preserved. Shelve life of fresh mushrooms vary from 1
day to 2 weeks depending on: structure and condition of the mushroom, relative humidity and
temperature of the environment and air movement over the mushroom in the package.
The shelf life can be extended by refrigeration at 1- 4 ⁰c and only suitable for short term
storage.
For long term storage, canning, pickling and drying processes are employed. These methods
are not suitable for all types of mushrooms because they modify the quality and taste of the
finished products.
VIII.
Canning:
This involves cleaning, blanching, sterilization, cooling, labelling and packing.
1. Clean the mushroom thoroughly and soak for 30minutes in water small amount of
ascorbic acid.
2. Rinse the mushrooms and blanch for 2 minutes
3. Place the blanched mushrooms in cans containing 2.5% Sodium chloride solution
(Dissolve 1.46g in 1L of water) and 0.5% citric acid
4. Seal the cans and sterilize in autoclave for 1 hour at 1210C
IX.
Pickling:
It similar to canning.
Special equipment:
2 pint jars, canning pot
Ingredients
1 pound oyster mushrooms 2 1/2 cups rice vinegar
1 small onion, sliced
1 tablespoon pickling salt
1 tablespoon sugar
1/4 teaspoon black peppercorns
2 garlic cloves, peeled and sliced
Procedure for pickling Oyster mushrooms
1. Wash oyster mushrooms well and chop them into pieces.
2. Bring a pot of salted water to a boil and simmer the oyster mushrooms for 8-10
minutes, until they’re tender.
3. In a medium pot, combine vinegar, onion, salt, sugar and peppercorns. Bring to a boil.
4. When the oyster mushrooms are tender, drain them well and transfer them to the
brine.
5. Cook mushrooms in brine for 5 minutes.
6. Divide bay leaves and garlic between two prepared pint jars.
7. Pack oyster mushrooms and onions into jars and top with brine, leaving 1/2 inch
headspace.
8. Use a wooden spoon or chopstick to remove air bubbles from jars. If necessary, add
more brine to return the headspace to 1/2 inch.
9. Wipe rims, apply lids and rings and process jars in a boiling water bath for 15
minutes.
10. When time is up, remove jars from canning pot and let jars cool on a folded kitchen
towel.
11. When jars are cool, check lids to ensure a good seal. Any unsealed jars should be
stored in the refrigerator.
12. Let pickles rest at least 48 hours before opening.
13. Sealed pickles are shelf stable for up to one year.
X.
Drying:
dried mushrooms are convenient for long-term storage and transportation.Mushroom are sun dried or oven dried at low temperatures up to a moisture content of 10 –
13%. Drying takes 2- 4 days.
Dried mushrooms are the put in put into clear polythene bags, kept in dry cool (2 – 5 0C) and
dark place. They polybags should be packed in cartons or wooden boxes in a low temperature
store
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