Causes of Spoilage in Salted Mushrooms and Detailed Prevention and Control Measures

During the salting process, if a film (pellicle) and bacterial blooms appear, it indicates that the surface has been contaminated by yeasts or molds. These can soften the tissue, cause it to lose its gelatinous quality, and lead to spoilage. If contaminated by putrefactive bacteria, proteins and amino acids can be broken down into indole, hydrogen sulfide, and other substances, producing off-odors and other toxic substances.

Causes of spoilage:

(1) Low brine concentration or high pH: Generally, the brine is required to have a salinity of above 22 Baume degrees and a pH between 4 and 5. Adjustments must be made promptly during the salting process.

(2) Improper salting method: Enoki mushroom (Flammulina velutipes) is not suitable for the dry-salting method (one layer of mushrooms and one layer of salt). Dry salting typically results in the upper layer becoming moldy and sour, the lower layer turning black, and only the middle layer remaining relatively normal. This is caused by uneven salt distribution among the mushroom bodies in the jar. The upper layer has less salt, and the mushroom bodies are often exposed to air, making them susceptible to contamination by bacteria and molds, leading to spoilage. After the salt dissolves, it sinks to the bottom, increasing the salinity of the lower layer and causing the mushroom bodies to turn black. The middle layer has moderate salinity, so the salting effect is relatively good.

(3) Poor brine sealing: During the salting and preservation process, the container opening must be sealed with brine so that the mushroom bodies are preserved below the liquid surface. When the mushroom bodies float to the surface and are exposed, prolonged contact with air will not only cause rot and spoilage but also destroy vitamin C (vitamin C) in the mushroom bodies through oxidation. In addition, the quality of the water used for salting also affects the quality of the processed product. Iron compounds or substances such as hydrogen sulfide in the water can cause the mushroom bodies to turn black. Therefore, the water quality must comply with the national drinking water sanitation standards.