After salt water mushrooms are stored for more than 3 months, acid film (or fungus flowers) may appear, the upper layer of mushrooms rots and smells, and slowly turns black, the whole barrel of mushrooms becomes waxy yellow, the juice is yellow and turbid, sour and smelly. , Causing losses.
(1) Acid film
There are two types of acid film, one is off-white or creamy yellow with wrinkled film, which is produced by the growth of film-producing yeast and pseudo-yeast on the surface of the salt solution; the other is milky white and smooth
Membrane, which is produced by hop yeast. These are aerobic, salt and acid resistant microorganisms that can oxidize sugar, ethanol, acetic acid, and lactic acid to produce carbon dioxide and water, which have an adverse effect on the quality of saltwater mushrooms.
To control the growth of these microorganisms, there are two methods:
1. Fill up the salt water, screw the lid tightly to isolate the air and form an oxygen-free state.
2. The saltwater of the brine rises above 22 Baume, and the pH drops below 2.5. You can also add 0.1% preservatives (such as sodium benzoate)
(2) Rotten and smelly
As mushrooms rise to the surface of the liquid and come into contact with the air, bacterial activities produce toxic gases such as indole, methyl indole, and hydrogen sulfide, which make them smelly. The way to overcome it is to use bamboo curtains to press the mushrooms under the liquid surface and keep the mushrooms out of the liquid surface.
(3) Mushrooms slowly turn black
Tyrosine produced by proteolysis is found in mushroom tissues.
Under the action of tyrosinase in the cell, melanin (melanin) is formed by oxidation. In addition, the interaction of amino acids and reducing sugars in the cells will also produce black substances, making the mushrooms black. The way to overcome it is to add 0.4% citric acid to restore the pale yellow color of the mushrooms.
(4) Mushrooms turn waxy yellow, turbid juice, and sour and tasteful. This can happen: one is excessive fermentation during the color conversion process (for the secondary pickling method), and the other is that the salt concentration is too low during pickling and the lactic acid bacteria , Heterogeneous lactic acid bacteria and bacterial activity. The way to overcome it is to add salt and pickle in time after the color changes, and pay attention to inspection during storage, and control it to be above 22 Baume.
