Wednesday, 6 June 2012

Shiitake mushrooms cultivation

Shiitake mushrooms cultivation is popular in the eastern countries. The product has a striking taste, high nutritional value, medicinal properties and high market prices. Shiitake mushrooms are at times also referred to as ‘Japanese’ type. Traditionally shiitake mushrooms cultivation is mainly done on hardwood logs. However its cultivation can also be on other substrates such as sawdust [from soft or hard wood], corn cobs, rice straw, and coir dust using the plastic bag cultivation technology. The substrates to be used for cultivation should also be sterilized instead of pasteurization due to the slower growth of mycelia, in order to avoid contamination and reduced production. Some commonly used substrates preparation formulations consists of 100kg sawdust, 1 kg ammonium sulphate, 5 kg rice bran, 5 kg urea, 1kg calcium hydroxide and 70% moisture. These materials should be composted for at least 30 days turning at 4 to 5 days interval until the compost turns dark brown and has no smell of ammonia prior to cultivation.

The compost bags are prepared and filled, and then spawning is done. Incubation follows in the darkroom at a temperature of 24 to 28 ºC. It takes about two months before the mycelia can completely penetrate the substrate. Another one month is required to allow the fruiting bag to mature completely. When the shiitake mushrooms mycelia begin to turn brown and ‘popcorns’ start to appear  on the substrate the bags are ready to be opened at the top and placed in the fruiting room. The cultivation room should be well ventilated and lighted for good fruiting body formation. The fruiting bodies start forming after two to three weeks. The room should be watered at least 1 to 2 times a day to avoid watering the shiitake mushrooms bags directly. This keeps the relative humidity at about 85 to 95% .The temperature for fruiting should be 10 to 20 ºC depending on the strain.

The fruiting bodies are ready for harvesting once they are slightly open. The bags will continue to fruit as long as the right conditions are maintained.
The yields can be upto 35% - 100% of dry weight of the substrate within 5 to 6 months. The produce can be stored fresh in the refrigerator in perforated polythene bags for at least 3 to7 days. Shiitake mushrooms are usually dried to improve smell and taste. Drying of Shiitake mushrooms  should be done gradually under the sun or in special driers with adjustable heat control, starting at 30 ºC and increasing every hour by 1 º to 2º, then 12hrs at 50 ºC and finally 60 ºC for one hour to increase the luster of the cap. In conclusion shiitake mushrooms cultivation is therefore a worthwhile agribusiness activity.