MUSHROOM CULTIVATION.

MUSHROOM CULTIVATION.

A potential venture for transformation of economic livelihood for poor farmers in peri-urban and rural areas of Uganda.

Introduction.

Mushrooms are fruiting bodies of fungi belonging to class basidiomycetes. Occasionally grow widely under favourable condition in natural forests, grassland. However when provided with optimum environment they can be grown indoor.

Edible mushrooms are medicinal with high quality protein, essential minerals ( Sodium, Potassium, Iron, Magnesium and Cobalamin), Vitamins (Ascorbic acid, Pyridoxine, Riboflavin, Thiamine) and their carbohydrates ranges from (3-38)%. Hence mushroom have an immune stimulating properties so they are beneficial for HIV sufferers.

Lack of awareness of the profitability of the mushroom venture, limited knowledge sources on mushroom cultivation and ignorance of the nutritional value of mushroom when aggregated, they contribute to the production of mushroom. In Uganda commercial cultivation of mushroom lacks statistical data due to few trained producing growers.

Types of mushrooms. 

Mushrooms are classified according to chemical composition.

Edible mushrooms; these are safe for human consumption. Examples include; oyster, true morels, chanterella, portobello, white button, shiitake, lion mane, flammulina, filiformis, maitake, cremini, porcini, chanterelles, black trumpet, hen of the woods, giant puffball, hedgehog and shimeji.

Poisonous mushroom; these are unsafe for human consumption and some can lead to death. Examples include; death cap, fly agaric, Satan's bolete, panther cap, fool's webcap, blusher, paxillus involutus, ivory funnel, fool's funnel, amanita smithiana, red-pored bolete.

Common cultivated mushrooms.

Oyster mushroom (pleurotis spp)

Button mushroom (agaricus spp)

Shiitake mushroom (lentinus spp)

Staw mushroom (volvarialla spp)

Economic global trend of mushroom production.

1. Market size.

The global mushroom market was valued $50.3 billion in 2021 and expected to grow at a compound annual growth rate (CAGR) of 9.7% from 2022-2030.

Currently it will grow from $66billion in 2024 to $71.62 billion in 2025 at CAGR of 8.5%.

2. Consumer interest.

Consumer interest in specialty mushroom has increased with retail sales of specialty mushrooms more than doubled in the past ten years due to the growing awareness of health and organic products.

3. Distribution 

Companies and producers are increasing distribution channels by collaborating with retailers and online growers.

4. Market shares.

Companies are using merges, acquisition and partnership to expand their market shares.

Mode of feeding.

Most grown oyster strains grown in Uganda are "saprophytic" these feed on dead and decomposing plant and animal debris.

"Parasitic mushroom" include ganoderma spp. These obtain nutrients from living plant hosts.

"Symbiotic mushroom" include termitomycetes spp.  It's a mutual benefit relationship between two living organisms.

Why venture in mushroom growing enterprise.

Advancement in technology has enabled domesticating of given mushroom species in-door.

Mushroom are cultivated on diverse agricultural and industrial wastes known as substrate.

Mushrooms yeild (100-200)%of the dry weight of the substrate depending on the management practices.

Mushrooms mature fast with a short growth cycle of 4 weeks.

Mushrooms can be grown throughout the year indoor.

Mushrooms require lesser capital with cheap resources.

Mushrooms production requires less space with high production rate per unit area.

Mushroom enterprise is easy to integrate and adapt in diverse crop farming enterprise.

The growing consumer interest to health and organic products provides a ready, stable and growing market.

Mushroom cultivation is a suitable source of employment to women, disabled, youths and unemployed with low income sources.

Requirements needed to start mushroom cultivation.

Temporary growing house.

Wire mesh

Substrate (coffee husks, rice husks, cotton seed husks, rice straw, legume trash)

Sterilizer implements. ( Drum, firewood, detergents)

Water

Bagging materials.

Spawn (certified mushroom seeds)

Lime or Gypsum.

Procedure for Oyster mushroom cultivation.

Soak the substrate overnight.

Drain the substrate on a wire mesh to 70% moisture content.

Put the substrate in the sterilizer and steam sterilize for 3 hours.

Leave the substrate to cool within the sterilizer.

Aseptically dispense (4-5) kg into the bagging materials.

Add about 100grams of spawn to each bag and seal.

Transfer the sealed bag (garden) to the incubation room ( dark and at temperature range (25 - 28(⁰C

Use a sharp razorblade, repeatedly slit the bag vertically open.

Mist spray the room regularly in the morning and evening to encourage high humidity in the room as to induce mushroom formation.

Harvest mushroom at the umbrella stage 

Utilize the substrate as animal feeds/ composite

Factors affecting mushroom cultivation.

1. Temperature 

Maintain 20-28⁰C for incubation.

At fruiting stage maintain 18-22⁰C for optimum yeild.

2. Humidity 

Ensure high humidity (80-90)% obtained through regular mist spraying in the morning and evening.

3. Ventilation 

Low oxygen and carbon dioxide content slows down growth. High carbon dioxide level are favourable for mycelial growth and high carbon dioxide level during fruiting lead to development of long stems and smal caps hence proper ventilation is essential for good yields.

4. Moisture content

Extremely high moisture content above 80% clogs airflow. Extremely low moisture content below 55%prevents growth. Optimum moisture content of about 70% is suitable for mushroom growth determined by "squeeze test".

5. pH

Mushroom prefer a slightly acidic medium (5-6). The pH drops during incubation because of the carbon dioxide given off. Lime can be added as a buffer to guard against pH changes at a rate of 1% of the wet weight of the substrate.

6. Illumination (light)

Mushroom require light for fruiting. Inadequate light can lead to long stems and small heads. Light suitable to read notes on a white paper is highly recommended.

7. Quality of spawn

Certied spawn ( mushroom seeds) free from contaminants, desired strain and not expired is recommended for desirable yields.

8. Particle size of substrate 

Optimum particle size of (0.5-2.5)cm enhance availability of nutrients and reduce risk of compaction whereas small particles result to compaction and big particles results to inadequate nutrients available to the mushroom.

9. Nutrient status of substrate, especially C:N ratio of substrate.

Fermentation ensures accessibility of nutrients to the mycelium. C:N ratio percentage of (30-40) is preferable for oyster mushroom.

Some substrate don't require fermentation. If fresh substrate were spawned the mycelium would die because of excessive heat generated by microbial activity 

Common mushroom diseases.

Mushroom diseases are classified into fungal diseases, bacterial diseases and viral diseases as stated below.

1. Fungal diseases include;

Dry bubble caused by verticillium spp.

Cobweb caused by cladobotryum spp.

Green mold caused by trichoderma viride

Wet bubble caused by mycogone perniciosa.

Mummy disease caused by pseudomonas aeruginose.

2. Bacterial diseases.

Bacterial blotch caused by pseudomonas tobasi.

3. Viral diseases

Dieback caused by various virus strains.

 

Symptoms of these diseases 

Green mold: green patches on mushroom buds and beds.

Wet bubble: white mat of mycelium that like cauliflower.

Mummy disease: tilted caps, curved stalks and spongy tissues.

Cobweb disease: Circular patches of cottony white mycelium.

Effects of mushroom diseases.

Less to complete crop failure. 

Lowers productivity.

Reduce quality of yields.

Shorten shelf-life of mushroom.

Controlling of mushroom diseases.

Dip a cotton swab in formalin solution and scrape off affected areas.

Discard the entire garden "cube" if the fungus attack more than half of it 

Burn/ bury contaminated cubes far from the mushroom room.

Post harvest handling of mushroom.

Mushrooms are best consumed as fresh. However in actual practice this may not be possible.

Storage of mushroom at high temperatures results to browning. Mushroom have a high respiration rate and hence proper attention should be given during storage. Common post handling practices adapted include 

1. Instant packing and refrigeration.

Freshly harvested mushrooms are packed polythene bags without making any holes. Immediately after packing they are stored at 5⁰C in a refrigerator. This extends the storage life for (3-5) days.

This process helps to reduce respiratory rate and minimize the water loss. In addition it reduces browning of mushroom and off-flavour development.

2. Freeze drying

The mushroom are sliced and immersed in 0.05% sodium meta bisulphate and 2% common salt for 30 minutes followed by cooling. This is then one minute at -12⁰C and stored at -20⁰C. This process extends the storage life for (3-4) months.

3. Dehydration.

This treatment involves "pre-treatment, drying and storage.

Pre-treatment 

Clean the mushroom and blanch it in boiling water for 2 minutes and immersed it in cold water for 2 minutes.

Dip the mushroom in water containing 0.2% potassium meta bisulphate and 1% citric acid.

Drying.

Sun-drying; the pre-treated mushroom is dried in open sunlight till it reaches 1/10 of the fresh product weight. After drying, it can be stored for 3 months. However colour may turn to brown and the final product appearance is not visually pleasant.

Drying in-flow drier; dry the pre,- treated mushroom at 60⁰C with heated sir (6-8) hours. This process lead to bring the final moisture level to (3-5)%

Vaccum drying; dry the pre- treated mushroom at 40⁰C under vaccum condition instantly. This process yeild a very good quality final product but costly.

4. Canning

Canning is adopted on a very large scale, especially for preservation of button mushroom. For canning purpose, the mushroom should be harvested at an early stage. The mushroom of uniform size are selected and stalks are cut before processing.

Procedure of canning.

Wash the mushroom in clean water to remove foreign materials.

Dip the mushroom in boiling water for 2 minutes, take it out and dip it in cold water for 2 minutes.

Fill the mushroom in the specialized can upto 3/4 capacities.

Add salt solution consisting of 2% common salt, 2% sugar and 0.3% citric acid just to fill upto the brim.

Place the lid on the can and keep the cans in boiling water/steam till the temperature in the center of the cans reaches (80-85)⁰C.

Seal the can on a seamee to get an air tight seal.

Sterilize the cans in an autoclave at 10Ib pressure for (20-25) minutes.

Keep the cans immediately after sterilization in clean cool water for cooling 

Wipe the the can with a dry cloth and store in a cool dry place. This process extends the storage life up to 12 months.