Introduction
Button Mushroom (Agarics spp.) is the most popular mushroom variety grown and consumed the world over. In India, its production earlier was limited to the winter season, but with technology development is produced almost throughout the country round the year in small, medium and large farms, adopting different levels of technology. Mushroom is one of the most important horticultural cash crops grown world over, and is least land dependent. A piece of land is required for building of infrastructure. The cultivation is done entirely indoors on substrates prepared from agricultural waste materials specially for the purpose of mushroom growing. Mushroom is a highly profitable cash crop in India, especially when raw materials and labour are available at cheap rates. Mushroom cultivation, which is of recent origin in India, has become popular all over the country especially with advancement in development of environment control systems. White button mushroom cultivation (Agarics Bosporus) was initiated at Solan, Himachal Pradesh in early sixties successfully. Since then mushroom cultivation has been taken up by private and government agencies all over the country. In hilly regions white button mushroom is commonly grown as a seasonal crop because of its low temperature requirement for cropping (15-18C), while as Oyster / Dhingra and paddy straw mushrooms are successfully grown in hot and humid regions, like coastal areas /peninsular India, under natural seasonal growing conditions. It is now possible to grow white button mushroom at any elevation/place with creation of necessary environment. Specially designed insulated cropping rooms are built to cut off the external environment with that of inside environment. The environment / climate inside the cropping rooms is simulated to exact conditions required for mushroom growth. This has enabled growers to harvest excellent crops.
Mushroom forms an excellent protein rich diet for human consumption. Mushroom is valued for its aroma, food value, mineral and vitamin content and fibre value. Mushrooms are one of the richest in protein content amongst the vegetables (3.5 - 4 percent protein content on fresh weight basis), and are valued for the highest content of folic acid required for healthy blood development in human beings. Mushrooms have a high content of fibre and potassium which are useful for lowering blood cholesterol level and control of high blood pressure respectively. Mushrooms above all, are excellent addition to the menu of vegetarians and are now being cultivated at hills and in tropical areas of India under controlled environment successfully. Mushroom cultivation is especially high on the priority list for export which can earn valuable foreign exchange for the country. It is more profitable and economic to grow mushrooms in areas with abundant raw materials and cheap labour, as it is no more economical to grow mushrooms in highly industrialized countries because of high cost of raw materials and Labour.
The entire infrastructure will be built at one place, and the site selected is nearer to the main road necessary for operational convenience. The composting unit is to be built closer to the main road and the bulk chambers will be built on the distant end of the composting yard for reasons of hygiene. The growing rooms should be built on the spawning end of the bulk chamber and away from the composting yard. The spawn production laboratory will be built in the ground floors. In this report details of the following will be given with structural design: of mushrooms, irrespective of external environmental conditions prevailing.
i) Composting yard consisting of phase-I chambers, bulk chamber / pasteurization chambers, composting platform and casing pasteurization chambers,
ii) Four environments controlled cropping rooms for raising of crop.
iii) Canning unit
iv) Spawn Laboratory
v) Training centre for “Mushroom Production Technology”
Cultivation Technology to Be Adopted
A) SUBTRATE PREPARATION/COMPOSTING:
Commonly cultivated white button mushroom Agarics Bosporus is one mushroom which requires substrate preparation with greater skill, as it does not grow best on unfermented Agro-wastes, as is the case with other cultivated mushrooms like Pleurites. The substrate/compost for button mushroom is prepared from agro-byproducts/wastes like cereal straw, sugarcane bagasse, barley/millet stalks, maize stalks and other such materials. The cereal straws/other straws are used as base materials, which are supplemented / enriched with nitrogen rich animal manures like horse dung / poultry manure and other such materials. The materials are wetted / blended in a definite proportion, subjected to solid state fermentation in 2 different phases and a selective medium prepared for the exclusive growth of mushroom mycelium.
The commonly available materials in the form of agro-wastes / by-products are generally used as base materials for compost making. The most common being the cereal straws (paddy straw /wheat straw), sugarcane bagasse, maize stems, barley grass, hay and other such materials. The
commonly used animal manures are the N-rich poultry manure, horse dung and other such materials, which are used as nitrogen rich supplements / activators and total nitrogen content brought to 1.7% of the total dry weight (carbon content) before starting. For this we add some nitrogenous fertilizers and bring the C:N ratio to 35:1 at start of composting process. The mesophilic microbes that have to initiate in the fermentation process with generation of heat in the compost require a basal C:N ratio of 35:1. The availability of base materials like cereal straws and supplements like poultry manure guides a grower for determination of a formulation for compost making. No formulation is recommended as such but the formulation is developed after assessing the availability of raw materials / supplements in a particular area and the costs at which these materials are available.
Base materials
Wheat straw, Paddy straw, Maize stems Jawar stem, Barley stems, Sugarcane bagasse, Hay
Animal manures
Horse manure, Mule dung, Poultry manure, Ixcreta from piggery
N-rich organic activators/supplements
Soybean meal, Cotton seed meal, Soybean cake, Cotton seed cake, Maize cob shells, Cotton seed hulls.
N-rich fertilizers recommended
Ammonium sulphate, Calcium ammonium nitrate, Urea, Other N-fertilizers.
1) Wheat straw - 1000 kg
Poultry manure (dry) - 500 kg
Wheat bran - 100 kg
Cotton seed cake - 60 kg
2) Sugarcane bagasse - 1000 kg
Paddy straw - 300 kg
Poultry manure - 800 kg
Urea - 15 kg
The entire composting process is accomplished in 2 phases, phase-I and phase-II. Phase-I is done in 2 parts, part-I is pre-wetting / mixing / blending and part 2 is outdoor aerobic fermentation either in a stack outdoors on composting platform or in a phase-I aerated bunker. This is followed by phase II process of pasteurization / conditioning.
Phase-I: Pre-wetting:
The raw materials are brought to the composting yard and straws are first wetted, either in a bag or by use of a sprinkler or water hose pipe (-6) day. The straw is thoroughly wetted and turned with forks/front loader so that all portions of straw heap receive water. The wetted straw with water seeping out at the cement floor is left as such overnight/48 hrs. to allow the moisture to be imbibed by individual straw cells in a heap. The water leached out during wetting is collected in a guddy pit, and reused the next day.
The straw is turned and wetted again on (-4) day after 24/48 hours on day-0 (depending upon the type of straw used – paddy 24 hours, wheat – 48 hours). The water from guddy pit is sprayed back onto the straw to utilize the nutrients leached out on first day wetting. The straw is again wetted and turned. This is again left standing in a wet heap for 24/48 hours, to permit water absorption and dewaxing of the wheat straw cells.
On day (-2) the additional composting ingredients like wheat bran, fertilizers, cotton seed cake and poultry manure are mixed with the wet straw thoroughly to blend the composting material thoroughly, and water if required.
PRESENT STATUS OF MUSHROOM PRODUCTION IN IN
The watering/blending are two important activities in compost making which are critical for making of a good compost. At this stage composting ingredients should have 75% moisture. The partially fermenting composting ingredients are left at the pre-wetting yard for another 24/48. The partially fermenting composting ingredients are left at the pre-wetting yard for another 24/48.
On day (0) the composting materials are stacked after thorough mixing/blending/watering. Moisture level of around 75% is maintained at this stage. With addition of poultry manure, the heating of the pile takes a vertical take-off & poultry manure works like a rocket fuel and results in tremendous heat production in first 24 hours after stacking.
Outdoor Composting:
The stack is made on the composting platform on 0-Day or alternatively the
ingredients are filled into a phase-I aerated bunker, for aerobic fermentation. The pile outdoors is made 5 feet wide & 5 feet high and length will depend on the quantity of the material. For outdoor composting, wooden/steel boards are used to give the stack a smooth vertical wall on all sides for proper aeration of the compost pile (chimney effect – meaning that hot air on escape from top will be replaced by fresh air going in from sides).
The stack is given 1st, 2nd & 3rd turnings on day 2,4 and 6 for proper mixing/blending of ingredients and watering of portions not properly wetted. The turnings facilitate uniform fermentation of ingredients/mixing and replenishment of fresh air into the stack for aerobic fermentation. Ensure that the temperature in the stack before each turning is around 70-75°C. Gypsum is mixed on 3rd turning when maximum ammonification has been achieved (0.4% ammonium at 3rd turning/at filling into phase-II chamber). The material is filled into the chamber quickly to preserve heat and phase-II operations resumed.
Alternatively, aerated bunker can be used in place of open stacks for phase-I composting process. The composting ingredients after pre-wetting are filled into the aerated phase-I bunker over the grated floor to the height of 6-8 fee. The material is left in the bunker for 48 hours for high temperature fermentation. The blower of the aerated floor is operated for 5-6 minutes every hour to replenish oxygen in the composting ingredients and drive out foul gases. The oxygen availability is made a limiting factor and with restricted oxygenation of the composting materials, lesser foul gases are produced & emitted. That is why this method is termed as eco-friendly. The composting ingredients are drawn out of phase-I bunker and put on the platform and after a few hours refilled into the phase-I bunker again. This helps in mixing/blending the materials well, inspect the composting materials for production of fire fang/moisture content, and apply corrections if required. As a matter of principal, the watering/mixing should be perfectly done during pre-wet operations and amount of water required should be blended into the material during the pre-wetting operations. The entire process of composting will go out of gear if this stage is not done religiously. The ingredients are allowed to stay in the bunker for another 48 hours and again drawn out 3rd time & poured onto platform after mixing gypsum with it.
The ingredients are monitored for temperature at each filling. The temperature in the core region goes to 70-75%/ or even up to 80°C, but bottom/sides/top show lesser temperature of around 60°C. It is in this region that useful thermopiles are left surviving to be of help in phase-II operation later.
The composting ingredients after solid state uniform aerobic fermentation in phase-I bunker for 6 days with emptying/refilling done after every 48 hours, is ready for filling into the phase-II (pasteurization chamber). The material is quickly loaded onto the grated floor of the pasteurization chamber to the height of 2 meters, chamber closed & the blower switched on.
PRESENT STATUS OF MUSHROOM PRODUCTION IN INDIA AND THE P
Phase-II: Pasteurization/Conditioning:
Phase-II of compost making starts after completion of phase-I of composting. The material after filling into the bulk chamber/peak heating chamber, is maintained in the closed chamber with switching on of the blower fan to equivalize the temperature of compost/air below & above compost. The heat is given out from fermenting compost and this results in heating of air above & below compost mass slowly. The compost is at a temperature of 45-50°C when filled into the chamber and slowly the air above shows temperature rise followed by rise in temperature in air in the plenum. The temperature is equalized in 6-8 hours or even 12 hours with blower continuously on and fresh air inlets closed. After equivalization of temperature, the steam is injected to increase the temperature of the compost as quickly as possible to pasteurization range (57-59°C air tempt.), which may take 8-12 hours depending upon the quality of compost in the chamber and capacity of the boiler. The time is noted when the air temperature above the compost and the plenum reaches 57-59°C. The temperature is held in this range for 8 hours for pasteurization process. The compost temperature may also be in the range of 58-60°C but air temperature should not be allowed to go beyond 59°C. Use of steam is made intermittently, if required, to maintain the air temperature (57-59°C) in the desired range during pasteurization process. After completion of pasteurization process, fresh air vent is opened 20% to let in fresh air for aerobic high temperature fermentation of the compost. The compost temperature tends to fall slowly on opening of fresh air vent and it is allowed to drop slowly to 48-53°C for conditioning process to resume. The temperature of the compost is held in this range for 5-6 days till the ammonia smell is no more discernible. After completion of conditioning, more fresh air is brought in by opening the vent to 50-100% and compost cooled down to 25°C before spawning. In tropical areas use of cooling coils is done to cool compost temperature to 25°C as ambient temperature in summer is around40-45°C. During the process of conditioning the blower fan is kept on non-stop, fresh air vent kept open at 20% fresh air with exhaust of gaseous air from inside through exhaust outlet. Steam can be injected, if required, to keep the compost temperature in the desired range. During the process of conditioning the ammonia (free/ bound) is converted to microbial proteins by thermophilic microbes (mostly fungi). Phase-I is done to bring composting materials to the stage of maximum ammonium production, and phase-II to facilitate the conversion of ammonia/ammonium to microbial proteins in the compost which is selectively utilized by mushroom mycelium later for mushroom production. The compost after completion of phase-II of composting should be dark brown in colour, dull & non greasy looking, with nitrogen content at 2.3 – 2.5%, moisture at 67 ± 1°C, pH in the range of 7-7.5 (even up to 8), and with no presence of off-odour/ammonia (to be detected by smell). If dragger tube is available, ammonia content should be below 3 ppm.
B) SPAWNING AND SPAWN RUN:
Spawning of the compost is done immediately after completion of composting process and when compost temperature has been brought down to 25°C. The grain spawn of A. bisporus is mixed with the compost under aseptic conditions and seeded compost filled into polythene bags or beds, compressed hard and levelled. The mouth of the polythene bag is closed loosely, rather folded to prevent evaporation of moisture from the compost. If filled in trays/shelves, the seeded compost after compression/levelling is covered with a clean newspaper sheet. Bags can be filled from 12”- 20” depth, shelves can be filled up to 8-10” depth. The newspaper is wetted daily to prevent moisture loss from bed. The desired quantity of spawn is directly mixed with the compost thoroughly (0.5-0.7% of wet compost weight) and seeded compost filled into the bag or shelf or tray. spawn can also be added to the compost by layer spawning method, top layer spawning or dibbling into the compost all over. All methods of spawning are at par, and it is the convenience of the grower that decides the method that the chooses for spawning. The spawned compost is placed inside a cropping room, maintaining at a temperature of 23 ± 1°C (air tempt.), RH of 95% and high CO2 conc. (10,000-15,000 ppm strain dependent) for effective spawn run. There is no requirement of fresh air during spawn run, and all vents are kept closed during the process of spawn running, which takes about 12-14 days. Entire compost mass turns light brown after spawn impregnation/spawn run. Ensure that pure culture spawn, freshly prepared, is used for spawning, which is done under aseptic conditions. The spawning area, tools, hands should be sterilized with formation before spawning is done. All the doors/windows in spawning area should be kept closed during spawning operation. The spawn running temperature for A. bisporus is 28°C ± 1C (air tempt.).
C) CASING AND CASE RUN:
PRESENT STATUS OF MUSHROOM PRODUCTION IN INDIA AND THE WORLD
Casing layer is a layer of soil 3-4 cm thick applied on top of spawn run compost and is a pre-requisite to fruiting in Agarics bisporus cultivation.
Casing materials: Earlier sub-soil material or organic matter rich soils were used as casing in button mushroom cultivation earlier. Presently peat is the most desirable casing material used worldwide with excellent mushroom yields and superior fruitbody quality. There are several other alternative materials now recommended for use as casing materials in white button mushroom cultivation. These are well decomposed Farm Yard Manure, well decomposed Spent Mushroom Compost, composted Coir Pith (Coir industry waste), decomposed powdered bark of some forest trees, paper industry waste etc. The casing materials should be soft, pliable, capable of tremendous water holding capacity, capable of permitting maximum air exchange / ion exchange and above all be deficient in nutrient materials supporting vegetative growth of the fungus. The casing materials should have C and N in unavailable form, otherwise there will be no fruitbody formation. The casing material should be almost neutral in pH with low electrical conductivity (400-600 μmoh). Sand, burnt paddy husk, ash and gobar-gas-compost are undesirable casing materials used by many growers in Indian in absence of viable casing materials. Sugarcane-mud press in combination with coir pith has also shown promise as a healthy casing material in India. Casing material should not be sieved but used as such with clumps, which permits more air spaces in casing? The casing surface should have small mounts and valleys.
Casing treatment: Casing material before application is steam treated at 65-70°C for 6-8 hours. The casing material is wetted to 25-30% water holding capacity, filled into the casing pasteurization chamber and steam injected into the chamber till temperature in the casing medium reaches 65-70°C. Hold the temperature in this range for 6-8 hours. The casing material is allowed to cool before application.
Alternatively, casing material is treated with formalin, using 1 litre of Formaldehyde 40 per 1 cubic meter (approx. 1000 kg) of casing material in concentrated form. Heap the wet casing on a cemented platform and apply formaldehyde to the casing directly @ one l /1 m3 and mix with a shovel. Cover the casing with a polythene sheet and seal the outer periphery by pouring sand/soil on outside margin. Allow the casing to stand like this for 24-48 hours in sun for fumigation effect. The formalin gas will be produced at temperature of 25°C and above which will kill all the living microbes, insect pest and fungi, rendering the casing medium safe for use. The casing material before use should be exposed to sunlight, spreading it over with clean tools and permitting the formalin fumes to escape into air for 2-3 days. Care should be taken to prevent re-infection of the casing materials. Store the treated casing material in a sterilized, clean room in polythene bag or synthetic cloth bags.
Casing application: Apply casing layer over levelled fully spawn run compost, 4-5 cm deep uniformly. Wet the spawn run compost by giving a light water spray, then apply casing (Avoid this practice in cultivation of Agarics bitorquis). Use metallic rings 4-5 cm wide or wooden buttons 4-5cm thick for application of uniform depth of casing layer. Water spraying should be given immediately after casing application to make the casing wet and bring it, to maximum water holding capacity. Care should be taken that the water does not run into spawn run compost. It is best to apply water to casing in a few instalments to bring it to maximum water holding capacity.
Case run and pinhead formation: Case run or impregnation of mycelium in casing in A. bisporus is done at a temperature of 24 ± 1°C, 95% RH and CO2 concentration upward of 7500 ppm (strain dependent). Case run in A. bisporus is done at 28°C (air tempt.) It takes about one week for complete case run at above mentioned environmental parameters. There is no requirement for fresh air introduction during case run. The case run is considered complete when mycelium comes in the valleys of casing layer. At this stage the environmental conditions are changed by lowering the temperature to 15-17°C (air), RH to 85% and opening the fresh air ventilation to bring in oxygen and exhaust CO2 to bring the CO2 concentration in a room down to 800-1000 ppm (strain dependent). This change in environmental parameters induces pinhead formation in 7-10 days (strain dependent) time. The pins develop into solid button sized mushrooms in another 3-4 days. The air in the cropping room is changed 6 times in one hour to maintain appropriate CO2 conc. in a crop room, as CO2 is at its peak during first flush (actually peaks at case run).
D) ENVIRONMENT CROP MANAGEMENT:
During the entire cropping period, the air temperature of 15-17°C and 85%. RH is maintained in the cropping room, with CO2 concentration held at 800-1000 ppm. The bed temperature should always be 1-2°C higher than air temperature to permit slow evaporation from casing, necessary for upward movement of nutrients in the compost for obtaining healthier flushes of mushrooms. A flush break lasts 4-5 days or even 7 days depending upon the intensity of the flush. In-between the flush breaks, no stray mushrooms should be left growing on the bed as it will delay the formation of next flush. If possible, raise the air temperature by 2-3°C for 24-48 hours in-between the flushes to accelerate formation of subsequent flushes.
During first & 2nd flush 6 air changes are resorted to per hours to get the desired oxygen – CO2 concentration in the cropping room, and after 2nd flush only 4 air changes are required as lesser quantities of CO2 are produced with passage of cropping time. Use CO2 meter for monitoring CO2 concentration in the cropping room at desired levels. Air temperature, RH and CO2 conc. are three important and vital parameters to be strictly maintained during pinhead formation to obtain a good flush of mushroom.
Deficiency in one out of above parameters during pinning will lead to reduced pin head formation thereby resulting in reduced mushroom yields. All the parameters are interdependent upon each other, and have to be maintained in the right range for optimal results. Possibly, that is the reason why computer-controlled environment maintenance is considered superior as it results in significantly higher mushroom yields for the reasons explained above. Computer control synchronizes the control of environmental parameters in the desired range for greater productivity.
Mushrooms are harvested when buttons are of 4-5 cm in diameter, tough, stout and hard. Hold the mushroom between your forefinger and thumb, rotate it gently to disconnect it from the mycelium in the bed. Dress the mushroom by cutting off the soiled stem portion and collecting different grades of mushrooms in different baskets. Apply fresh casing at places where mushrooms have been removed. Add water at the rate the mushrooms have been harvested, i.e. for every kg of mushroom harvested add 1 litre of water after harvesting. Do not allow the casing to dry, as it will result in sealing of casing and formation.
Watering: Mushroom contains 90% water and that should give us an idea how water is important for the crop raising. Mycelium gets water from compost during spawn run and compost + casing during case run and from casing during fruit body formation. Water level in casing can be maintained in 2 ways at optimal level for growth of mushrooms. One is by regular water spraying when pins are pea sized and second is maintenance of RH at 85% during cropping, ensuring slow evaporation from crop beds for upward movement of nutrients in the compost. If one of the factors, water spraying/RH maintenance during cropping is disturbed, its effects crop productivity. Low RH in the room will encourage quick drying of casing, thereby effecting normal development of the fruit body. Low RH during cropping will result in drying of beds, light weight mushrooms, discoloration of mushrooms and crop losses. Drying of casing will seal the casing medium and result in formation of mat which becomes imperious to water, and results in tremendous crop losses. Water has to be replenished in casing to accommodate the water loss from casing due to mushroom growth and evaporation into the room air. It is not desirable to have 100% RH in the cropping room during cropping as it will not permit slow evaporation from crop beds, thereby preventing the nutrient upward movement in the compost and loss of CO2 + heat into the room air for removal by the AHU. This fact has always to be kept in mind while raising a crop of mushrooms and importance of water realised. Bed moisture and RH are two different factors, directly dependent upon each other. Bed moisture loss by way of crop growth is desirable, as it will ensure harvest of healthy/solid mushrooms but this loss should be replenished immediately and as much of water added to the bed that equals to the weight of mushrooms harvested. That should be the rule of the thumb, as far as watering during cropping is concerned (1 kg mushrooms harvested/1 litre of water added to casing). Avoid watering of beds at pin breaks. The casing should be wet enough when fresh air is brought in and room temperature lowered. That wetness should be sustained till pin heads become pea sized, and that is the stage when bed will require additional watering to allow pea-sized pins to develop into button sized mushrooms. Water management in mushroom crop management is the most critical of factors, requiring experience and skilled application. Watering to beds requires quantification at each stage, and the trained manpower handling watering will ensure proper water management in the cropping room. To monitor the RH in the cropping room, use two ordinary stem thermometers in the cropping room, placing one in the casing/compost bed and one hanging in the air nearby (few cm apart). Ensure that bed temperature is always 1-2°C higher than air temperature, which confirms that the air circulating in the room is humidified enough to prevent heavy evaporation from crop beds. When the air temperature is greater than the bed temperature it indicates the air in the room is dry and is removing moisture + heating from the crop bed, thus showing decreased bed temperature. This is an undesirable situation and will require quick remedial measures to prevent crop losses. Remedy is to increase RH to appropriate levels immediately, ensuring smooth crop production. Computer control of AHU for climate creation in the crop room ensures application of cropping parameters with precision during spawn run, case run and cropping. Use clean water free from salts, heavy metals and other impurities for watering of the crop beds. Water that is good enough for drinking/watering for vegetable/field crops should be good enough for mushroom cultivation. It is desirable to test the quality of water before the mushroom growing is started at a particular site. Test the water for pH, salts, heavy metals like iron/lead and other undesirable residues. Do not use sewage water for watering of crop beds during mushroom cultivation. Avoid use of chemicals/pesticides during crop raising to harvest chemical free mushrooms. Fungi are very efficient in uptake of pesticides from the substrate, and use of pesticides/other harmful chemicals should be avoided as far as possible.
For pest control, selective use of pesticides is recommended under advice. Preventive measures for exclusion of pests during mushroom crop raising is the best method of pest control in mushroom cultivation. Once the infection is established in the crop beds, eradication by chemical control is difficult task and not very successful in mushroom cultivation. Pesticide/chemicals leave heavy residues in the fruitbody, as mushrooms have to be harvested every day after spray application, and hence should be avoided. Use of biocontrol agents/plant products for pest control should be resorted to, if necessary.
E) HAVERSATING AND AFTER CARE:
The mushrooms when fully mature/grown to its right biological stage (hard button size) are ready for harvesting. Button sized mushrooms 2-5 cm in cap diameter, with closed veil and hard pileus is ready for the harvest. Hold the mushrooms between your forefinger and thumb, rotate the mushroom clockwise/anticlockwise to disconnect it from mycelium in the casing. Cut the soiled stem portion and collect the cut mushroom in a basket grade-wise. Do not drop the stem cuttings on the floor or the bed, as these will invite undesirable organisms to develop on it, thereby starting a problem in the cropping room. Clean the beds/floor after harvesting. Pour fresh casing materials at places where mushrooms have been removed/harvested, then spray water over the crop beds to leave it in excellent condition for development of the next flush.
Remove browned pins/mushrooms, if any, from the bed with hand and pour fresh casing at these places. If bunching is observed, address climate controls for creation of optimal environmental conditions during pinhead formation. If onion sized mushrooms/drum sticks are observed, correct air circulation in the room for effective CO2 removal from crop beds. Lack of air movement over crop beds and accumulation of CO2 creates this type of situation on the crop beds. Long stemmed mushrooms are again the outcome of CO2 accumulation in the air around crop canopy due to faulty air movement/air circulation in the cropping room.
Mushrooms after harvest are separated into different grades, packed in PP bags/card board boxes and preferably chilled at 4°C for 6-8 hours before sending to the market. The pre-market chilling enhances the shelf life of mushrooms. While harvesting care should be taken to keep the pileus free of casing soil so that the mushroom is not stained. Washing of mushrooms is undesirable, especially washing with Potassium metabosulphide solution to make these extra whites for reasons of increased acceptability in the market. Unwashed mushrooms stay fresh for a longer period. Mushrooms should be handled carefully, and not bruised during the harvest operation. Bruising will turn the pileus dark/pink on exposure to air. While packaging mushrooms in PP bag, ensure that a small hole (0.2 mm) is made in each PP bag to prevent the development of aflatoxins in transit or storage.
Button mushroom can be stored at 4°C for a few days without any deterioration in its quality but it is desirable to consume/market the fresh mushrooms immediately after harvest. Since button mushroom has a very short shelf life, it cannot be stored for longer periods and hence will require to be processed for longer storage. Mushroom are best preserved in brine solution after blanching, either in cans or jars. The processed mushrooms stay in good condition for over a period of 1 year if canned properly under aseptic conditions. It is possible to transport canned mushrooms in containers over longer distances without any deterioration in its quality. But fresh mushrooms can be transported short distances only in refrigerated vans/by air to reach a remunerative market. Mushrooms can also be freeze dried for export and freeze-dried mushroom retain original food value, flavour, colour and texture. But this method is expensive as the machinery has to be imported from an industrialized country at a very high cost.
F) POST HARVEST MANAGEMENT:
E) Harvesting and after care:
Packing and Storage
Packing and Marketing
The fresh mushrooms after harvest are best packed in plastic pin nets / polythene bags with a small hole, sealed and cold stored at 4-50C for 6 hours before sending to market. This enhances the shelf life of fresh mushrooms. If the mushrooms are to be sent to a distant market, the packets can be packed in an insulated GI box, with small ice pack put in layers in between mushroom packets. But for longer storage it is best to can the fresh mushrooms. The fresh mushrooms are best packed in plastic punnets and covered with a polyform. It is recommended to have a cool chain for transport of fresh mushrooms to distant market as indicated above.
With availability of environment-controlled cropping rooms, hybrid strains of mushrooms can be grown with exhalent yields. There is tremendous scope for marketing a mushroom fresh. Hybrid strains of white button mushrooms can be grown successfully in above designed mushroom growing rooms with perfect environment control, with ensured production. Hybrid mushrooms are good in look, taste and vigour, and are preferred in markets in both in India and western countries over the non - hybrid strains growing earlier.
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