Due to a slow selling season this year, some growers may be hanging on to roots for an extended period for future sale. If handled properly, dried ginseng roots should have a long storage life. There is minimal scientific information on the exact storage/shelf-life of ginseng, but by following some basic principles used for other dried root crops, ginseng should still be marketable up to 3 to 5 years after harvest.
There are 6 main things that affect storage/shelf life of dried products:
- Product Surface Area
The more moisture there is in the root, the faster it will degrade. Insufficiently dried roots can lead to mould growth. Even if the root is dried properly, small amounts of moisture re-absorbed from humidity in the air can facilitate chemical reactions in the root that lead to loss of quality. Roots should always be stored in a low-humidity environment. This can either be achieved by sealing well-dried roots into plastic bags or storing unsealed roots in a humidity-controlled room. Relative humidity in the storage room should never exceed 50% and should ideally be much lower. Humidity less than 15% will prolong shelf life as much as possible, but may be difficult to achieve.
Exposure of roots to light can lead to chemical changes on the surface of the root, a process called photodegradation. For most ginseng growers, this should not be an issue because roots are usually already placed in barrels or boxes that exclude light. This would mostly apply to roots stored in bulk in a room that is not completely in the dark. Avoid exposure to light as much as possible.
Exposure of roots to oxygen will lead to oxidation of the surface of the roots, which will alter the chemical quality of the roots. Since modified atmosphere storage is probably not an economic option for ginseng growers, the only way to control this is to vacuum pack and seal the ginseng roots. Even with regular exposure to oxygen, whole roots should still have a long storage life, but storage life will be extended to as much as five years if oxygen is excluded.
Both warmer temperatures and fluctuating temperatures can accelerate the chemical degradation caused by excess moisture, light and oxygen. The colder the temperature, the slower any degradation will be. Freezing is an option but is probably not worth the added expense. Keep temperatures steady and low for maximum shelf-life. Temperatures should not exceed 21°C at any time and ideally be at or below 10°C the majority of the time. Temperature and humidity interact, so temperature can be maintained a bit higher if humidity is very low.
All the factors listed above will work from the outside of the roots in. As a result, products with more surface area will degrade faster. Ground ginseng will have the shortest shelf-life (<1 year), followed by fibrous roots and root slices, then small roots, then larger roots. It is best to keep the roots in the whole form for as long as possible.
Even if all the above factors are controlled, the product can be destroyed by pests if left alone with no pest controls. Rodents and insects that can live in low-moisture products (e.g. Indian meal moth) are the main concerns. Rodents can be controlled with bait stations and ensuring roots are stored in vessels that are impenetrable to them. It is unknown what insect pests, such as Indian meal moth, may affect ginseng. These are best controlled by sealing the products into containers. Meal moths and other similar insects can chew through cardboard and thin plastic, so these are insufficient to control these pests. Cold temperatures will limit the development of insect-related problems. Ensure the storage area is free of other plant/animal debris such as dead leaves, branches, dead insects and general dust as these may be initial sources of insect pests. Insect traps are often used in other storage facilities to monitor for insect issues, but since it is unknown what insects may affect dried ginseng, these are not advised for ginseng. Monitor the storage regularly and contact OMAFRA if an insect issue develops and we may be able to assist with monitoring and control options.
Consistent monitoring of the storage room is required to ensure humidity remains low, temperatures are constant and low, and pests are not becoming an issue.