Mushroom Culture

PHT - Preservation of Mushrooms

A. Harvesting:

• Proper stage of harvesting have been worked out in case of most of the cultivated mushrooms.Generally they should be harvested while the partial veil are still intact or before they open.
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Fig. 10.1 Harvesting button mushrooms gently with two fingers and a thumb
Fig. 10.2 Harvested mushrooms along with their rootbuts

• The time and stage of harvesting matters a lot from the marketing point of view. Button mushrooms are harvested with delicate hands with the help of two fingers and a thumb.
• Harvesting is the most labour intensive activity in mushroom cultivation as individual mushroom has to be handpicked at the proper stage as in case of tea industry.

 

Fig. 10.3 Paddy straw mushrooms- ready for the harvest
Fig. 10.4 Heavy flush of milky mushrooms

B. Grading, packing and storage:

• Soon after harvest, mushrooms have to be cleaned and graded before sending to the market or storage in a cool atmosphere. The grading and sorting is done according to their colour ( pure white , slightly brown , damaged ), size , stage of the cap or partial veil ( Intact , slightly open , open ), length of the stem etc. Grading is generally done on the basis of size of the button, shape of pileus and opening of gills , also known as buttons, cups and umbrellas , respectively . The mushrooms for fresh market are packed in plastic containers, perforated polythene bags of 100 gauge thickness or loose bags at varying packages.

Fig. 10.5 & 10.6 Button mushrooms kept in the container after
removal of rootbuts and packed in in plastic trays after grading



Fig. 10.7 & 10.8 The milky mushrooms and button mushrooms packed in perforated polythene bags after harvesting and cleaning.

• Mushrooms can be stored in cold storage at 1-2ºC for a number of days or in deep freezers at below 0ºC or in vacuum freezers where water in cell walls and interhyphal spaces is evaporated with a vacuum that brings temperature from ambient to 2-3ºC in 15-20 minutes. Mushrooms should be packed generally in polythene bags ( perforated ) and placed gently inside the cardboard boxes with some paper packings so that they do not get pressed or jerked during transportation.

C. Transportation:

• Mushrooms can be stored at low temperature ( 4-5ºC ) for 3-4 days only. These are to be transported in cool environment, either in ice boxes or in refrigerated vans and once they reach in the market , they must be immediately transferred to the deep freezer.

D. Preservation of mushrooms:

a) Canning and Freeze drying:

• For canning, mushrooms are harvested at the appropriate stage i.e. before opening, cleaned properly in cold water, blanched by dipping in boiling water for 4-5 minutes, graded and filled in standard canning jars which are then filled up to the brim with hot and boiling citric acid or vinegar solution and cooked by passing through a seamer for 4-5 minutes before sealing with a cap or lid . These sealed can jars are then pasteurized in an autoclave at 10 lbs. psi for 30-40 minutes, cooled and kept under observation for sometime before labeling.
• In freezing method, ninety percent water content of mushroom fruit bodies become crystallized and mushrooms are held together by ice crystals rather than by their own cellular structure. The ideal method of drying and freezing is the freeze-drying technique. Here every part and content of mushroom is preserved, including the flavour, form , nutritional and medicinal contents. But it is a very costly method and only few can afford it.

b) Drying:

• When mushroom production increases manifold, it becomes difficult to market fresh ones, especially in favourable peak season. During that period prices also come down and it is not affordable for small growers from hilly areas to send their produce in the market. The only alternative for them is either to dry their produce or go for preservation. Most of the mushrooms have 90-95 % water, hence very difficult to dry them and some like A .bisporus, Calocybe indica , Stropharia sp etc; can not be dried as they possess poor rehydration quality and become brown and black due to heat. Many other mushrooms like species of Pleurotus, Auricularia, Morchella, Lentinulla, Ganoderma, Flammulina, Sparassis, Pholiota etc; can be dried and packed for long duration storage.

Fig: 1) Sun dried fruit bodies of Morchella, 2) Flammulina, 3) Pleurotus and 4) Ganoderma

• In hilly areas people generally stitch garlands of freshly picked mushrooms in steel wire or thread and keep them hanging in the sun or near their kitchen for 6-7 days for drying and thus preserve them. Now-a-days apart from sun drying, bigger and sophisticated Mechanical Dehydrators are available in the market. A good dryer should have the capacity to dry mushrooms within 24-48 hours by passing warm air not hotter than 110 ºF. The damaged and insect infested fruiting bodies should never be dried but discarded. Once properly dried ( 0.1 - o .5 % moisture content ) , these should be carefully packed in airtight polythene bags and hermatically sealed so that air does not pass through it.

 

E. Marketing:

• Since mushrooms are highly sensitive and early perishable products, these should reach to the market as early as possible, immediately after the harvest. In most of the farms, workers get up at about 1or 2 AM in the morning and operations like harvesting, cutting, cleaning and packaging are completed by 4 AM so that they may reach to the market along with their produce by 6 AM. The white colour is preferred by the consumers, hence to increase the whiteness and shelf life, most of the growers in Asian countries treat or wash their button mushroom produce in 0.05 per cent KMS or Potassium metabisulphite solution for 1 minute ( 5 g in 10 litre water ) .
• In India mushrooms are sent to the market either in loose packing or in poly packets of different weights and sold through auction in vegetable markets or through vegetable vendors. Mushrooms packed in attractive boxes and covered with attractive papers are known to fetch higher price as compared with the mushrooms in ordinary packings.
• Individual farmers going to the markets for selling their produce are generally exploited by the traders. The growers must form a cooperative society and members should abide by its rules and regulations which will work for the production as well as marketing of their mushrooms in a joint manner. Society can also get the latest market trend through internet and inform its members regularly so that they may be able to sell their produce in the market where higher prices are being offered.