Prevention
A lens inventory should be made and the high use, less valuable lenses may not require any really special care particularly if one is in a dry and cooler climate than say Florida or in the tropics. High value, less often used lenses and gear it might be worthwhile to consider some special care.
It seems to be a given that the fungus spores are everywhere and that they require a humid atmosphere and a warmish temperature range.
Addressing the atmosphere side of the equation presents a number of options. The free exchange of air should be controlled by an air tight method.
A: Zip Lock freezer plastic bags. There are inexpensive, are see-threw, low cost, reusable, low weight, durable and are about 99.9% air and water tight. They also take up little space in storage and one can wrap a lens and insert it in the factory storage case or pouch for storage and travel. They come in many sizes and are available in most any super market. OK for air travel.
B. A water tight Pelican style case. Great for storage and travel all though every time it is opened the atmospheric lock will be broken. Spores and humidity can enter. These are usually sealed by an o ring or foam gasket method. Everything you have in the case will get a fresh load of humidity and spores. OK for air travel.
C. Storage cabinet. This method slows down the exchange as most cabinets are not air tight but do a good job of excluding dust and spores. They don’t do too much for humidity by themselves. Again every opening of a cabinet brings in fresh spores and humidity too. Great information on engineered "dry cabinets" can be found here:
http://www.totechamerica.com/productincludes/faq.php Keeping that enclosed space of your choice really air-dry and spore free: A. Desiccant (silica gel) bags. These are inexpensive and dry the air out by absorbing the water molecules similar to a sponge. OK for air travel. Obviously they have an absorbing limit and you can bet old ones have reached their effective maximums and should be replaced with dry fresh ones or you are fooling yourself. Many have saturation indicators on the bag to warn you the max has been reached.
(Sorb-It packaged silica gel desiccant is made from amorphous silicate. It is a hard, translucent material with an extremely high capacity for moisture at temperatures below 75°F and at humidity levels above 40% RH. Sorb-It is designed to control moisture levels within packaged products. The function of Sorb-It when controlling moisture is like that of a tiny sponge with millions of microscopic pores. Under very low humidity conditions, a small amount of water vapor will be adsorbed in the smallest pores. As humidity increases, the large pores will begin to fill. Unlike a sponge, however, Sorb-It remains dry and free-flowing, even at maximum adsorption capacity) For information
:Desiccant City: Sorb-It Silica Gel Desiccant bags can be refreshed by warming and driving the water out. You can Google desiccant recycling.
B. Rice: Probably better with kung pao chicken but it does have a small water absorbing ability. Some restaurants used to put it in the salt shakers before they start adding anti stick chemicals to salt grains.
C. Camphor: Sometimes used to displace water molecules in machinists tool boxes. This would keep iron and steel tools from rusting. I am not sure what the camphor vapors can do to plastics, electronics or lens coatings. Personally I would avoid it for camera equipment.
D. Atmosphere displacement: If an air tight housing (Zip Lock bag) is used you might consider and atmosphere flush of nitrogen, or dry compressed air. You can obtain dry air in pressure cans that are used for watch making, electronics and such. Dry air is also available in SCUBA dive tanks if in the field if you do under water photography. I think I would avoid CO2. There are some studies of fungi stimulation in CO2 atmospheres. You might consider a wine preservation gas. This one is reportedly a nitrogen and argon mix and is used to displace oxygen in wine bottles to stop oxidation and degrading.
http://www.wineenthusiast.com/wine-enthusiast-private-preserve-wine-preserva...CJ You obviously cannot take a pressure cylinder aboard an airplane.
E. Ultra violet light: This might be used for large cabinet storage. They use UV lights in washing and dryer machines to sterilize. UV light is also used in water reclaimation plants to kill bacteria and such. This should kill any cabinet spores. A small UV light would improve a not-so air tight cabinet. A paper on UV light used for building fungi control:
http://aem.asm.org/content/67/8/3712.full