GB2317898A - A system for the manufacture of mushroom spawn - Google Patents

Abstract

Water is mixed and cooked with a granular substrate material which absorbs water. The exterior of the substrate is coated with calcium carbonate. The coated substrate is then bagged and mounted on a mobile rack and then delivered to a sterilising chamber. The mouth of each bag is held open during sterilisation. The rack is discharged into a bacteriologically clean cooling room and then on demand is delivered into an inoculating compartment. Inoculant spawn is placed in each bag which is sealed. Each of the bags is shaken and incubated for a preset period, shaken and incubated for a further period. Thereafter the bags are cooled and packed in packing cases.

Description

"A System for the Manufacture of Mushroom Spawn" This invention relates to a system for the manufacture of mushroom spawn.

In mushroom growing when a crop fails it is usually difficult to determine the cause of failure which is often attributed to bad spawn which may or may not be the true cause of the problem. This is obviously expensive for the spawn producer. The spawn producer does not control how mushroom growing mediums are prepared and how they are used by growers. As the spawn is a live organism is may be aversely affected by improper use in the preparation of growing mediums and in the growing of mushrooms.

With many growing mediums often clumping of mushrooms on the growing medium can occur which leads to wastage.

The present invention is directed towards overcoming the problem.

According to the invention there is provided a system for the manufacture of mushroom spawn, comprising the steps: mixing water and a granular substrate material, absorbing the water in the granular substrate material forming a wetted granular substrate material of a desired moisture content, mixing calcium carbonate with the wetted granular substrate material, coating an exterior of the wetted granular substrate material with calcium carbonate, discharging the granular substrate material into plastic bags, a measured quantity of granular substrate material being delivered into each bag, each bag having a microporous filter in a side wall of the bag, mounting a plurality of the filled open bags on a mobile rack, delivering the rack to a sterilising chamber, sealing the chamber, applying a vacuum to an interior of the chamber, injecting steam into the chamber, raising the temperature within the chamber to a selected sterilising temperature, maintaining the temperature within the chamber at the selected sterilising temperature for a preset time period, removing the rack from the sterilising chamber, delivering the rack directly from the sterilising chamber into a bacteriologically clean cooling room having a filtered atmosphere, cooling the sterilised substrate material to a desired temperature in the cooling room, delivering the substrate material on demand from the cooling room to an inoculating compartment, inoculating each bag of granular substrate material in the inoculating compartment with inoculant spawn by delivering a desired quantity of inoculant spawn into the bag and sealing the bag, applying a label to each bag with a code corresponding to the batch of spawn and the batch of sterilised substrate material in the bag, shaking each bag for mixing the spawn through the substrate material in the bag, delivering each bag to an incubation room, incubating the spawn in the sealed bags at a preset desired temperature for a selected time period, shaking the bags during the incubation time period, cooling the bags and packing the bags in packing cases.

In a preferred embodiment the system includes preparing an inoculant spawn by selecting a number of master spawn samples from a refrigerated spawn bank, placing a spawn sample on a number of plates containing a nutrient medium for the spawn, growing a spawn culture on the nutrient medium, selecting a number of the spawn cultures, photographing each selected spawn culture, taking a spawn plug from each spawn culture and placing the plug in an associated master bottle containing a sterilised grain substrate material, the plug being placed against a side wall of the bottle, incubating the master bottles for growing a spawn culture on the grain substrate material in each bottle, taking selected master bottles and distributing the contents of each master bottle into a number of culture bottles, each culture bottle containing a sterilised granular substrate material, incubating the culture bottles for growing inoculant spawn in each culture bottle, and delivering culture bottles on demand to the inoculating compartment.

In another embodiment the system includes holding open each bag of granular substrate material on the rack while the bag is within the sterilising chamber.

Preferably the system includes supporting each bag on its side in an inclined position on a tray on the rack with an open end of the bag uppermost, engaging an open end of the bag with an arm mounted above the tray for holding the bag open during sterilising of the contents of the bag.

In one embodiment the substrate is rye.

In another embodiment the substrate is vermiculate.

Preferably the substrate further includes pumice.

In another embodiment the substrate is used in preparing a growing medium which comprises vermiculate, pumice, wheat bran, gypsum, calcium carbonate and water.

In another embodiment the system includes labelling each packing case with a label bearing a code denoting the batch of spawn culture and the batch of substrate material contained within the bags in the packing case, the label bearing the code in duplicate, a first code being applied on a fixed part of the label which is attached to the packing case and a second identical code being applied on a peel-off removable label part which is removably attached to the fixed label part.

In a further embodiment the system includes incubating the spawn in the bags for 7 days at 25.5"c, shaking the bags, further incubating the bags at about 18.5 c for between 2 and 3 days, cooling the bags to about 10 c over a period of between 10 and 20 hours, and then delivering the bags to a cold store for chilling to between 0 - 1 c.

The invention will be more clearly understood by the following description of some embodiments thereof, given by way of example only, with reference to the accompanying drawings, in which; Fig. 1 is a schematic illustration of a system for the manufacture of mushroom spawn according to the invention; Fig. 2 is a schematic illustration of the preparation of inoculant spawn according to the system; Fig. 3 is a perspective view of a mobile rack used in the system; Fig. 4 is a side elevational view of the rack; Fig. 5 is an elevational view of an identification label used in the system; and Fig. 6 is a perspective view of the identification label, in use mounted on a packing case.

Referring initially to Fig 1 which is a schematic illustration of the system. A granular substrate material such as rye is delivered to a cooker 10 and is boiled in the cooker 10 in water to raise the moisture content of the grain to approximately 45%.

The wetted grain is then delivered to a mixer 12 together with calcium carbonate. The calcium carbonate is mixed with the wetted grain for coating an exterior of the wetted grain with calcium carbonate. This facilitates the handling of the grain and the subsequent sterilisation of the grain described later.

The grain is then filled into plastic bags at a bagging station 14.

Each plastic bag has a microporous filter in a side wall of the bag which provides a microbial filter but allows through passage of air, allowing materials in the bag to breathe when the bag is subsequently closed.

A number of the bags, which are still open at this stage, are arranged on a mobile rack 15 (Figs. 3 and 4). The rack 15 has a tubular frame 42 mounted on wheels or castors 43. Inclined tray receiving rails 44 extend between a front and a rear of the rack 15 at each side of the rack 15. Bag support trays 45 are engagable with the rails 44. The trays 45 are vertically spaced-apart on the rack 15. A number of bags 46 of the granular material are mounted on each tray 45 with a mouth 47 of each bag 46 uppermost. Each bag 46 is laid on its side on a tray 45 which supports the bag 46 in an inclined position with a mouth 47 of the bag 46 uppermost. An upper side 48 of the mouth 47 of the bag 46 is engagable with a hook or arm 49 mounted above the tray 45 on the rack 15 to hold the mouth 47 in an open position. This advantageously assists in the sterilisation of the material within the bag 15 which is described later. A label with a code designating the batch of grain is applied to the mobile rack 15. The mobile rack 15 is then delivered into a sterilising chamber 16 such as an autoclave.

After sealing the sterilising chamber 16 a vacuum is applied to an interior of the chamber 16 to draw air out of the chamber 16. In this regard the arms 49 holding open each bag 46 are advantageous in preventing the collapse of the bags 46 which would inhibit the free flow of air from the bags 46. Steam is injected into the sterilising chamber raising the temperature within the chamber 16 to a selected sterilising temperature. Again, holding the bags 46 open assists in the rapid and complete sterilisation of the grain within each bag 46.

After sterilisation the rack 15 is discharged directly from the sterilising chamber into a bacteriologically clean cooling room 17 having a filtered atmosphere. Within the cooling room 17 the sterilised grain is allowed to cool in the bags 46 over a number of hours.

The cooled grain is then delivered on demand in the bags 46 on the racks 15 from the cooling room 17 directly into an inoculating compartment 18 which is also maintained in a bacteriologically clean condition.

The sterilised grain in each bag 46 is then inoculated with an inoculant spawn by delivering a desired quantity of inoculant spawn into the bag 46 and then sealing the bag 46.

A label is applied to each bag 46 with a code corresponding to the batch of inoculant spawn and the batch of sterilised grain in the bag 46.

Downstream of the inoculating compartment 18 each bag 46 is shaken 19 for mixing the inoculant spawn through the grain in the bag 46. Each bag 46 is then retained in an incubating room 20 for incubating the spawn. Initially the bags 46 are incubated for 7 days at 23.50c.

Then the bags 46 are again shaken 21 to ensure even distribution of the spawn throughout the sterilised grain. Then the bags 46 are incubated 22 for a further 2 - 3 days at a temperature of approximately 18.5"c. Thereafter the temperature is lowered to approximately 10 c over a period of 10 - 16 hours, typically overnight.

Then the bags 46 are moved to a cold room 24 at which the temperature is maintained at about 0 - 1 c. The bags are stored in the cold room 24 until the quality has been passed and the bags 46 are then packed into cases and dispatched.

An identification label 50 (Figs. 5 and 6) is applied to each packing case 51, at a packing station 25, the label 50 bearing a code 52 denoting the batch of spawn culture and the batch of grain contained within the bags 46 in the packing case 51. It will be noted that the label 50 carries the code in duplicate, a first code being carried on a fixed part 54 of the label which is adhesively attached to the packing case 51 and a second identical code being carried on a peel off removable label part 55 which is removably attached to the fixed label part 54. A rear face of each label 50 has an adhesive coating for sticking the label 50 to a packing case 51 or the like. A cover strip 56 (shown in broken outline in Fig. 6) is mounted on the rear face of the label 50 over the peel-off removable label part 55 so that when the label 50 is applied to the packing case 51 the removable label part 55 does not stick to the packing case 51 but can be readily, easily peeled away from the remainder of the label 50. Thus, advantageously when the bags 46 of mushroom spawn are delivered in the packing case 51 to a producer of mushroom growing compost the producer can readily easily peel off the removable label part 55 and attach it to a report which also identifies the compost batch with which the mushroom spawn is mixed to enable the spawn used in each batch of compost to be fully traced.

In another embodiment instead of using grain as a substrate for the spawn other substrate material can be used such as vermiculate which is used in the production of a casing medium. The production of the casing medium is generally similar to that described previously for the mushroom spawn on the granular substrate. It is particularly preferred that the substrate used for the casing medium comprises in combination vermiculate, pumice, wheat bran, gypsum, calcium carbonate and water. The use of pumice has been found particularly advantageous for retaining moisture and slowly releasing moisture into the casing medium over a period during mushroom cultivation. Ideally, also a heavy grade or coarse-grain vermiculate is used as this has been found to be particularly effective in providing an easily handled open structure to the casing medium. The wheat bran provides a food source. It is envisaged that various other food sources may be substituted for the wheat bran if desired. The gypsum and the calcium carbonate provide control of the pH of the casing medium and also help to prevent clumping of the casing medium. The casing medium produced according to the invention has been found to be more effective than the conventional casing mediums of peat, compost or clay. The casing medium according to the invention has improved handling characteristics being easier to spread and evenly distribute. This eliminates clustering during cultivation of mushrooms and a more consistent mushroom product is produced. Further, the growing cycle can be consistently reduced to about 19 days, thus improving productivity.

Referring now to Fig. 2 which is a schematic illustration of the preparation of inoculant spawn. A number of master spawn samples are selected from a refrigerated spawn bank 30, a spawn sample 31 being placed in the centre of agar plate 32. A spawn culture 33 is grown on the nutrient medium and then the best 5 plates 32 are selected. Each of these spawn cultures is then photographed to provide a record of the structure of the culture. A spawn plug 35 is taken from each plate 32 and placed in an associated master bottle 36 containing a sterilised grain substrate material 37. The plug is placed against a side wall of the bottle 36. Thus advantageously the growth of the spawn plug 35 within the bottle 36 can be clearly seen. A number of the master bottles 36 are prepared. The master bottles 36 are incubated for growing the spawn culture on the grain substrate material in the bottle 36. Master bottle 36 having a good spawn development are then selected and the spawn coated granular material then delivered into a number of culture bottles 40 for growing inoculant spawn in each culture bottle. Once the spawn has been developed in the culture bottles 40 the cultures bottles 40 are delivered on demand to the inoculating compartment 18 for use as previously described.

It will be appreciated that the invention provides a system for the manufacture of a high quality mushroom spawn minimising the risk of failure by the manner in which the spawn and the associated substrate material is prepared. Further, the system provides for the tracing of the different batches of spawn produced and the growing mediums with which they are mixed to assist in the accurate determination of the causes of crop failure when it occurs and assist in the elimination of unreliable spawn strains on future production where appropriate. The invention is not limited to the embodiments hereinbefore described which may be varied in both construction and detail.

Claims (12)

Claims

1. A system for the manufacture of mushroom spawn, comprising the steps: mixing water and a granular substrate material, absorbing the water in the granular substrate material forming a wetted granular substrate material of a desired moisture content, mixing calcium carbonate with the wetted granular substrate material, coating an exterior of the wetted granular substrate material with calcium carbonate, discharging the granular substrate material into plastic bags, a measured quantity of granular substrate material being delivered into each bag, each bag having a microporous filter in a side wall of the bag, mounting a plurality of the filled open bags on a mobile rack, delivering the rack to a sterilising chamber, sealing the chamber, applying a vacuum to an interior of the chamber, injecting steam into the chamber, raising the temperature within the chamber to a selected sterilising temperature, maintaining the temperature within the chamber at the selected sterilising temperature for a preset time period, removing the rack from the sterilising chamber, delivering the rack directly from the sterilising chamber into a bacteriologically clean cooling room having a filtered atmosphere, cooling the sterilised substrate material to a desired temperature in the cooling room, delivering the substrate material on demand from the cooling room to an inoculating compartment, inoculating each bag of granular substrate material in the inoculating compartment with inoculant spawn by delivering a desired quantity of inoculant spawn into the bag and sealing the bag, applying a label to each bag with a code corresponding to the batch of spawn and the batch of sterilised substrate material in the bag, shaking each bag for mixing the spawn through the substrate material in the bag, delivering each bag to an incubation room, incubating the spawn in the sealed bags at a preset desired temperature for a selected time period, shaking the bags during the incubation time period, cooling the bags and packing the bags in packing cases.

2. A system as claimed in claim 1 wherein the system includes preparing an inoculant spawn by selecting a number of master spawn samples from a refrigerated spawn bank, placing a spawn sample on a number of plates containing a nutrient medium for the spawn, growing a spawn culture on the nutrient medium, selecting a number of the spawn cultures, photographing each selected spawn culture, taking a spawn plug from each spawn culture and placing the plug in an associated master bottle containing a sterilised grain substrate material, the plug being placed against a side wall of the bottle, incubating the master bottles for growing a spawn culture on the grain substrate material in each bottle, taking selected master bottles and distributing the contents of each master bottle into a number of culture bottles, each culture bottle containing a sterilised granular substrate material, incubating the culture bottles for growing inoculant spawn in each culture bottle, and delivering culture bottles on demand to the inoculating compartment.

3. A system as claimed in claim 1 or 2 wherein the system includes holding open each bag of granular substrate material on the rack while the bag is within the sterilising chamber.

4. A system as claimed in claim 3 wherein the system includes supporting each bag on its side in an inclined position on a tray on the rack with an open end of the bag uppermost, engaging an open end of the bag with an arm mounted above the tray for holding the bag open during sterilising of the contents of the bag.

5. A system as claimed in any preceding claim wherein the substrate is rye.

6. A system as claimed in any of claims 1 - 4 wherein the substrate is vermiculate.

7. A system as claimed in claim 6 wherein the substrate further includes pumice.

8. A system as claimed in claim 7 for in the substrate is used in preparing a growing medium which comprises vermiculate, pumice, wheat bran, gypsum, calcium carbonate and water.

9. A system as claimed in any preceding claim wherein the system includes labelling each packing case with a label bearing a code denoting the batch of spawn culture and the batch of substrate material contained within the bags in the packing case, the label bearing the code in duplicate, a first code being applied on a fixed part of the label which is attached to the packing case and a second identical code being applied on a peel-off removable label part which is removably attached to the fixed label part.

10. A system as claimed in any preceding claim wherein the system includes incubating the spawn in the bags for 7 days at 25.5"c, shaking the bags, further incubating the bags at about 18.50c for between 2 and 3 days, cooling the bags to about 10 c over a period of between 10 and 20 hours, and then delivering the bags to a cold store for chilling to between 0 - 10c.

11. A system for the manufacture of mushroom spawn substantially as hereinbefore described with reference to the accompanying drawings.

12. Mushroom spawn whenever produced according to the system as claimed in any preceding claim.