Where can I use What Disinfectants?
Food contact surfaces are different than general sanitation (GS) areas on a mushroom farm. Disinfectants used on walls, floors and compost or casing handling equipment may not necessarily be approved for use on any FCS. Examples of FCS on a mushroom farm are casing rings, scratching tools, water equipment, baskets, lugs, tills or other mushroom packaging containers, harvesting knives, hangers, portable lights or other tools which come in contact with mushrooms or mushroom harvesters.
Mechanical harvesting equipment, conveyors, sorting or packing lines or other food processing or handling equipment, e.g., slicers, mushroom washing and blanching equipment are other examples of FCS, that must be cleaned with the proper disinfectants or thoroughly rinsed with potable water after use with non-FCS chemicals.
All disinfectants/sanitizers are inactivated by dirt load or organic matter loads. Therefore, for the most effective disinfecting, remove all dirt and debris before sanitizing by thoroughly brushing and cleaning all surfaces with soap or detergent and then rinsing with generous amounts of water. Disinfectants are commonly used in breezeway foot baths and the rapid increase of dirt load in these baths has to be considered to insure an effective concentration is maintained. Another concern is worker safety. Only a few chemicals available can be used where nonimpervious shoes or boots are worn.
Dip tanks and foot baths are often filled with some type of disinfectant. The rapid accumulation of dirt and organic matter in these containers will make the disinfectants quickly inactive. Therefore, cleaning or rinsing equipment before dipping is recommended. Any harvesting equipment must be rinsed unless an approved FCS disinfectant is used. Footbaths also raise an issue with worker safety, since only some products are registered to use ONLY with impervious (impermeable) footwear. A general rule is to ensure the proper Personal Protective Equipment (PPE) is used for each chemical.
Spawn/casing crews should use high-pressure hot water to clean their spawning equipment because some chemicals may deteriorate on the bearings or other moving parts. The casing equipment, buckets, cart, track, around the doors, the wharf area and the truck can be sprayed with phenols, quats or idodiphors, however all equipment that comes in contact with compost or casing layer must be thoroughly well rinsed with potable water. Chlorine and several types of oxidizing agents can be used, but rinsing will prolong the life of the equipment. Some people feel that good old soap and water will work just as well.
Make sure that other indirect or inadvertent contact does not occur with either the crop or food contact surfaces. Examples of this would be drift or splashing, use of an aerosol or fogging agent, intake through air ducts, etc.
The most common use for disinfectants may be the sanitation of breezeways (walls, floors and doors) or picking halls. However, it is critical that all picking boxes, trays, and tills must be removed until the area is dry and all volatiles have dissipated. Potential drift may migrate to harvesting containers causing unwanted residues and product damage.
Aerosol application of disinfectants is allowed, however, air handling equipment must be turned off until the product dries and volatiles have dissipated. When using FCS sanitizers, air handlers may be left on to sanitize the internal coils.
HVAC equipment is often a concern for carry over of disease from crop to crop. It may be a common practice on farms to clean and disinfect the coils and ducts of the air handling equipment. Although this equipment is not considered FCS, the potential for a chemical used to clean this equipment to be dissipated throughout a cropping room is a concern.
Unintentional contact with mushroom compost or casing material is a concern because of the resulting inadvertent residues (possibly in only the ppb levels) that could remain on the mushroom tissue. This inadvertent contact may occur when equipment is washed and sanitized prior to daily usage. Several fruits and vegetables have some type of residual tolerance for different types of disinfectants. Unfortunately, at this time, residues for some of the disinfectants used in the mushroom industry have no tolerance established for mushrooms. Efforts by Penn State, IR4 and AMI are under way to pursue some type of "inadvertent tolerance" label for the important disinfectants used in the industry.