Key Technical Points for High-Quality and Safe Production of Edible Fungi
High-quality and safe production of edible fungi is an important part of the sustainable development of the edible fungi industry. It helps save resources, protect the environment, improve the competitiveness of products in the international market, increase the trade volume and price of exports, and raise the income of mushroom farmers. In recent years, with the increase in cultivated varieties of edible fungi, the broadening of types of cultivation resources, the expansion of cultivation area and the extension of cultivation regions, some production areas arbitrarily change formulas in pursuit of high yields and add some chemical components with unclear uses and mechanisms; and in one-sided pursuit of labor saving, they adopt some unscientific production management measures; in addition, due to the impact of the environment and water quality on the cultivation environment, incidents of contamination in edible fungi cultivation occur from time to time. After China's accession to the WTO, many products must undergo strict inspection in the international market, and a food market access system must also be implemented domestically. Therefore, it is necessary to propose and implement high-quality and safe production of edible fungi, improve product quality, and make products meet the new requirements of "natural, nutritious, and health-promoting."
For safe production of edible fungi, cultivation management should grasp the following principles: first, ensure the safety of raw materials, including the safety of sawdust, cottonseed hulls, bran, crop straw, casing soil materials, and various additive components used as culture substrates. Raw materials contaminated by miscellaneous fungi must not have the contaminated parts reused for cultivation, in order to prevent the accumulation of harmful substances; second, the environmental hygiene and water quality of the cultivation site must comply with the standards and requirements of food production, and water directly sprayed on the fruiting bodies must meet drinking water standards; third, in pest and disease control and the management of the production and processing environment, the principle of prevention first must be implemented, and it is absolutely not permitted to spray pesticides directly on the fruiting bodies. When pesticides must be used, low-toxicity and high-efficiency biological agents should be selected, and the timing and dosage of pesticide use should comply with the regulations for the safe use of pesticides. For space disinfection, ultraviolet disinfection and 75% alcohol disinfection are recommended.
The following 6 specific measures should be implemented well.
(1) Selection of the surrounding environment of the cultivation site. Edible fungi cultivation should be carried out far away from places that may cause contamination. The surrounding environment should meet food hygiene requirements, with no pollution sources or dust. When selecting a cultivation site around towns, even more attention should be paid to staying away from densely populated residential areas and main highways, and it is also necessary to prevent contamination caused by urban household waste, harmful waste gas, wastewater, and excessive human activity.
(2) Selection of topography and landforms. The ideal site for an edible fungi cultivation site should be chosen in a place facing south with a broad terrain, clean water sources, and abundant cultivation resources, while maintaining air circulation to facilitate the growth and reproduction of aerobic edible fungi; as an environment for cultivating green food and organic food, the atmospheric environment should meet the Grade I standard in the national "Ambient Air Quality Standard," and water quality should meet drinking water standards. For edible fungi cultivated with casing soil, such as Agaricus bisporus, straw mushroom, Agaricus blazei, and oyster mushroom, in addition to meeting the soil quality requirements suited to their respective cultivation characteristics, they also need to meet the standards in the "Control Requirements for Various Pollution Indicators in Soil" within the "Environmental Technical Conditions for Green Food Production Areas."
(3) Selection of raw materials. Currently, artificially cultivated edible fungi are all saprophytic fungi, and they are cultivated using agricultural and forestry by-products as the main raw materials to prepare culture substrates. Selecting pollution-free raw materials is an important basic step in preventing contamination of edible fungi products. For those using sawdust as the main cultivation raw material, safety testing should be conducted in advance. If pesticide residues exceed the standard, methods such as soaking in water and fermentation can be used to reduce the residual content before use; for those using manure and straw as the main cultivation raw materials, there is a greater chance of contamination, such as pesticide residues and heavy metal cadmium, so necessary tests should be conducted on the relevant components of various raw materials before cultivation, and raw materials with low levels of harmful components should be selected as culture substrates. During cultivation, various edible fungi should strictly use materials according to the formula, and the composition of the formula should strictly implement NY5099-2002 "Safety Technical Requirements for Edible Fungi Cultivation Substrates."
(4) Control of raw material processing and preparation
Strictly control the processing environment so that raw materials are not contaminated by harmful substances during processing, and prevent the mixing in of harmful oil stains and sawdust from aromatic tree species, etc.; all raw materials in the culture substrate should be safe, and the culture substrate should be prepared strictly according to the formula. Do not arbitrarily add fertilizers, nutrient agents, or other components that one believes can increase yield. The tools and machinery used should also meet safety and hygiene requirements.
(5) Control of cultivated varieties and cultivation modes. At present, nearly 50 species of edible fungi and medicinal fungi can be artificially cultivated, and nearly 100 species can be domesticated for artificial cultivation. Because the suitable temperature, humidity, and growth speed for the mycelial growth of various fungi differ, and their speeds of decomposition and assimilation ability for external substances also differ, for example, some varieties have a strong ability to accumulate certain metals, and some varieties themselves produce formaldehyde during metabolism. Therefore, if products have special requirements for certain components, the characteristics of nutrient metabolism of each fungal species should be considered. For example, oyster mushrooms are relatively likely to accumulate heavy metals, and this accumulation ability also varies by variety. The correlation between cultivation modes and contamination should not be ignored either. For casing soil cultivation, the safety of the casing soil material should be controlled; for bag-removed cultivation mode, when cultivating in beds, attention should be paid to the safety of the soil on the beds and the safety of water quality when soaking; for non-bag-removed cultivation, attention should be paid to the cultivation environment and the safety of water quality used for watering.
(6) Control of the cultivation management process. This mainly refers to the control of water quality and the hygiene of harvesting tools. The water quality directly sprayed on the fruiting bodies must meet drinking water standards; the water quality for soaking fungus bags must at least meet the standards for drinking water for poultry and livestock. Harvesting tools should meet the hygiene requirements for food raw materials. When harvesting products for special uses, harvesters should also wear special gloves, etc.
In short, in the process of edible fungi production, attention should be paid to the environment and all links in production, and NY/T3912-2000 "Environmental Technical Conditions for Green Food Production Areas" and the green food product quality standards in NY-5095-NY-5099, such as "Shiitake Mushroom," "Oyster Mushroom," "Agaricus bisporus," and "Black Wood Ear," as well as the "Safety Technical Requirements for Edible Fungi Cultivation Substrates," should be strictly implemented, so that edible fungi products can become not only pollution-free food but also green food or organic food.