Growing Oyster Mushrooms (Pleurotus ostreatus) at home

Pleurotus ostreatus, the oyster mushroom, is a common edible mushroom. It was first cultivated  in Germany as a subsistence measure during World War 1and is now grown commercially around the world for food. 
Culinary uses 

The oyster mushroom is frequently used in Japanese, Korean and Chinese cookery as delicacy: it is frequently served on its own, in soups, stuffed, or in stir-fry  recipes with  soy sauce. Oyster mushrooms are sometimes made into a sauce, used in Asian cooking, which is similar to oyster sauce. The mushroom's taste has been described as a mild with a slight odor similar to anise. The oyster mushroom is best when picked young; as the mushroom ages, the flesh becomes tough and the flavor becomes acrid and unpleasant.

Oyster mushrooms are widely cultivated and used in Kerala, India  where a wide variety of dishes are prepared from them. Oyster mushrooms are mainly cultivated in large clear  polyethylene  bags with buns of hay layered in the bags, and spores sown between these layers.

Oyster mushrooms contain small amounts of arabitol, a sugar alcohol,  which may cause gastrointestinal upset in some people.

Manual of instructions fully copied here for future reference and illustrated below:

Opening the box on 10/12/13 found the octopus or coral form that forms sometimes inside the box before opening due to lack of light

Is is completely edible and was cook and eaten that same day

Here we see images of primordial evolving into fruiting bodies  on 12/18/13  this white- beige form grows  between 55-75 F 

They needed moist and were misted 3 times a day and covered with humidity tent

Fruiting bodies fully developed by 12/21/13

.... Only after 11 days, the first harvests was made on 10/21/13

Producing substrate bags

These materials were taken from the FAO Website  from a program called Mushroom cultivation for people with disabilities 

http://www.fao.org/docrep/004/ab497e/ab497e07.htm#TopOfPage

1. Prepare materials:

• Plastic bags (polypropylene 7” x 12.5”)
• Plastic necks (about 4 cm diameter)
• Cotton plugs Cover filters (square piece of filter paper)
• Rubber bands Sawdust (cover top of substrate pile with rice sacks to maintain humidity)
• Rice bran
• Calcium sulfate
• Calcium carbonate
• Magnesium sulfate

Note: Substrate is the material used to grow mushrooms. This material or substrate is a mixture of all ingredients or “food” necessary for mushrooms to develop. Although sawdust is the most common and easy to use basic material for making mushroom substrate bags, other alternate and sometimes lower cost materials can be used. For example, in Asia, because of intense rice cultivation, rice straw can be used since straw is readily available in most rural areas. Because of its lower cost (and local availability) it may be better suited as a substrate than sawdust. Furthermore, rice straw generally generates higher yield and better quality mushrooms; both texture and taste of mushrooms are improved when using straw instead of sawdust. Nevertheless, straw needs to be prepared before use requiring harder work, and fermentation for a period of 9 - 12 days.

2. Preparing rice straw as substrate:

Put straw in grinder to reduce its size. Soak paddy straw 100 Kg. With water and mix with urea 1-2 % by weight, ferment for 3 days. Turn over the pile, then mix with 2% lime and ferment it again 3 days. Turn over the pile again, mix with 0.2% magnesium sulfate, and ferment 3 more days. The last turn over makes the straw readily composted for using as substrate. Check moisture and for a urea smell. If there is no urea smell and the moisture is 65-75%, the substrate is ready for packing. If there is some urea smell, it is necessary to ferment further until there is no more smell. Then pack in size 8” x 12” PP. Bags.

3. Substrate preparation

100 kg

Sawdust

Add to sawdust

5 kg	Rice bran
2 kg	Calcium sulfate
1 kg	Calcium carbonate
0.2 kg	Magnesium sulfate
0-1 kg	Sugar

Note: Substrate recipe should serve as a reference. Recipe can be changed by adding some rice flour, sticky rice flour, corn flour, cassava peels, cotton waste, Soya-bean residue, and other nutritious agricultural waste. In cool climates, it is possible to use additives or complementing materials up to 20%. Beware: for hot climatic zones, do not use more than 7.5% additives. (If rice straw, recipe needs to be modified as above mentioned)

4. Weigh all components using scale.

5. Mix well all ingredients in mixer or manually using shovels or paddles

6. Add water to keep moisture content between 65-75 %.

7. Make sure all ingredients are well mixed and that there are no lumps.

8. Sitting on floor, fill plastic bags with substrate using small shovel.

9. Compact substrate by hitting bags with empty bottle, hand.

10. Place plastic ring on bag

11. Pull out top of bag through plastic neck.

12. Fold-down on plastic ring.

13. Tie with rubber band.

14. Introduce stick with pointed head through plastic neck of bag to make hole almost to the bottom of the bag; DO NOT TOUCH BOTTOM of bag.

15. Check weight of bags (should be between 800-1000 grams per bag)

16. Prepare plastic caps to close bags by adding cotton.

17. Close bags with plastic caps.

18. Fill iron racks (9 bags per rack for commercial chamber).

Transfer bags to pasteurization chamber.

Multiplying spawn on sorghum seeds

These materials were taken from the FAO website from a program called Mushroom cultivation for people with disabilities 

http://www.fao.org/docrep/004/ab497e/ab497e07.htm#TopOfPage

1. Prepare materials:

• Sorghum seeds
• Bottles (flask type)
• Cotton (gauze)
• Paper squares 7 cm x 7 cm
• Rubber bands
• Alcohol lamp
• Alcohol bottle

Note: Various types of grains can be used: Sorghum, millet, wheat

Grains must:

• Have been recently harvested
• Contain few broken kernels
• Little contamination
• No fungi, no insects
• No more than 12% humidity

2. Soak sorghum for one night; 2 liters of water per 1 kg of grain.

Wash and strain sorghum seeds to remove all water.

3. Steam sorghum seeds for 30-45 minutes to soften grains and cook about 25%.

4. Drain water and spread sorghum seeds to cool down and decrease moisture.

5. Fill ¾ of bottle with sorghum seeds.

6. Carefully prepare cotton plug

7. Tightly plug mouth of bottle with cotton and leave out for ventilation.

8. Transfer all prepared bottles to the sterilization chamber.

Close chamber. Fire-up burner or stove to heat chamber. Make sure to release all air from the chamber before starting. Keep pressure in the chamber at 15 lb./sq.inch. or 121^o Celsius for 30 minutes for small chambers and 45 minutes for medium chambers.

Let bottles cool down.

9. Transfer bottles to a clean and cool place.

10. Bottles must be cleaned and well prepared.

Prepare the well verified PDA bottles

11. Clean laminar flow chamber using alcohol.

12. Transfer PDA, sorghum seed bottles, paper and rubber bands in laminar flow chamber. Light UV lamp for 10 - 15 minutes before starting. Place needle in alcohol.

Turn off UV. Clean both hands with alcohol and insert hands into the chamber.

13. Using 2 fingers, take out needle, pass through fire as to burn alcohol, and disinfect needle. Make sure the needle turns red.

14. After the needle cooled down to normal state, use needle to cut small square (5mm x 5mm) of PDA with mycelium (white color).

15. Close bottle immediately. Remain near flame at all times.

16. Using other hand flame around the mouth and shoulder of the sorghum seed bottle.

Using other fingers, open spawn bottle near flame to avoid contamination.

17. Insert needle and inoculate sorghum seeds with PDA mycelium by placing small square piece in the middle of the bottle. Make sure the PDA mycelium does not touch anything before entering the sorghum seeds bottle.

Note: The mouth of the bottle should be near the flame. The mouth should remain higher than the bottom part at all times. Do not touch mouth of bottle with piece of PDA.

18. Close bottle immediately.

19. Place square paper over cotton and tie with plastic neck or rubber band.

20. Label inoculated sorghum bottles writing: Date, Spawn no., ref., and inoculation time.

Note: It takes about 10 - 15 days to get full-grown sorghum grain mycelium, depending on the species.

21. Keep mature sorghum seeds in a cool place or in the vegetable compartment of the refrigerator. Check for infection regularly.

22. Remove contaminated bottles.

Transfer contaminated bottles to cleaning site. Clean bottles as normal glassware.

23. Observe and collect data. Take notes to draw conclusions.

Note: A loss of about 3% is to be expected