Detailed Explanation of Fresh-keeping Methods for Edible Fungi and Introduction Notes

I. Quick-freezing method

Suitable for keeping oyster mushrooms and similar fungi fresh. After harvesting the fresh mushrooms, use scissors or a knife to separate them into individual fruiting bodies, rinse them clean, and sort them by size and by tenderness. Bring water to a boil in a large pot, then add the fresh mushrooms; the amount of fresh mushrooms added should be 20%-30% of the boiling water volume. Stir with a slotted spoon or spatula in one direction; when the oyster mushrooms become soft, turn them over, and once the pot comes to a boil again, scoop them out and place them in a large vat filled with cold water. After cooling, scoop them into a sieve to drain, then pack them into non-toxic plastic food bags at 1 kg or 0.5 kg and seal. Put the mushrooms into food crates and store them in a -18°C cold storage.

II. Low-temperature method

Suitable for the storage and transport of edible fungi such as straw mushrooms at 60%-70% maturity. Use wooden crates or plastic crates 40 cm high; place a 5 cm thick layer of crushed ice on the bottom, cover with plastic film, place 20 cm thick fresh straw mushrooms on the film, and cover with plastic film. Spread a layer of crushed ice on the film, stack the crates one by one and load them for transport. Alternatively, use cardboard boxes 25 cm high, and immediately send them into a refrigerated truck with a cooling unit, lowering the temperature to 14°C. The above two methods can extend the storage period of straw mushrooms by 3-4 times.

III. Cooling method

Suitable for keeping edible fungi such as shiitake mushrooms fresh. Put the fresh mushrooms into plastic bags 30 micrometers thick and store them in a 1°C environment; the fresh-keeping period can reach 18 days, 13-14 days at 6°C, and 5 days at 15°C.

IV. Controlled atmosphere method

Suitable for keeping mushrooms and similar fungi fresh. Use silicone rubber film to make gas exchange windows, inset into the side walls of plastic bags, to keep mushrooms fresh; the effect is significant within 3-5 days. Alternatively, after removing soil, sand and other debris from freshly harvested mushrooms, pack them into wooden crates. The thickness of the packed mushrooms is 30-35 cm. After packing, seal the crate opening and store in an 18-20°C environment.

V. Chemical method

Generally suitable for the fresh-keeping of all edible fungi. The chemical fresh-keeping method using mushrooms as an example is introduced below.

1. Salt solution

Soak the mushroom bodies in a 0.7% salt solution; the effect is better 4-6 hours after picking.

2. Sodium metabisulfite

Soak in 0.01% sodium metabisulfite water for 30 minutes, scoop out and drain, then pack into plastic bags for storage; under 10-15°C conditions, the fresh-keeping effect is better.

3. Kinetin

Soak in 0.01% 6-aminopurine solution for 10-15 minutes, then take out and store conventionally.

4. B9 spraying

Place the mushrooms on a clean plastic film and evenly spray once with 0.1% daminozide (B9), then spray once more after 3-5 minutes. Then put them into plastic bags and store in a dark place; under 5-10°C conditions, they can be stored for 8 days.