Dry cleaning versus wet cleaning in grain processing plants

Housekeeping in Grain Processing Plants
 

In grain processing plants, wet cleaning is not considered necessary to control microbial growth, if the equipment and environment remain dry. Most grain processing plants use dry cleaning procedures to prevent grain contamination, because wet cleaning provides favorable conditions for microbes. Dry cleaning methods include sweeping, brushing, scraping, vacuuming, using pressurized air, etc. 

Developing a housekeeping program

Develop a written housekeeping program that outlines all cleaning activities and the frequency at which these should take place. House keeping programs need to cover all areas where grain is handled and stored, including exterior and interior surroundings and grain-contact surfaces, such as bins and elevators.

• Dry cleaning versus wet cleaning in grain processing plants
   

• Developing a housekeeping program
   

• General guidelines for housekeeping in grain processing plants
   

• General guidelines for wet cleaning sanitation

General guidelines for housekeeping in grain processing plants

• Ensure the grain storage conditions (temperature and humidity) remain the same during cleaning  to prevent moisture accumulation.
   

• When using pressurized air, make sure to relocate or protect all exposed grain to avoid cross contamination. For example: use grain pile covers, tarps or other material that will not contaminate grain.
   

• Make sure grain contact surfaces (table tops, inside surface of carts, bins, etc.), grain handling equipment and tools that are in direct contact with grain, are clean and free of foreign material (ex: rust, lubricating grease, cleaning compounds) before operation begins.
   

• Clean overhead equipment (ex: lights, pipes, beams, vent grids) often enough to prevent insect infestation, mold, or accumulation of dust, grain residue and foreign matter.
   

• Make sure that floor sweepings, dust and dockage created by cleaning are not reintroduced into the grain flow.

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• Clean grain spills quickly.
   

• Clean areas and surfaces that are not in direct contact with grain (ex: floors, walls, scales, tables, platforms) regularly and make sure to schedule regular maintenance and cleaning.
   

• Clean service equipment or equipment that is no longer in use regularly and leave it either open to facilitate access or completely covered to avoid grain and dust accumulation.
   

• Make sure areas or surfaces that are not likely to contaminate the product are cleaned periodically (ex: walls behind large pieces of equipment, stairways, windows, floors).
   

• Clean and maintain air handling systems and filters regularly to allow proper dust extraction.

• Bins

• After grain is transferred, grain dockage easily accumulates under the false bin door or on the bin floor. Make sure these areas are cleaned regularly to avoid insect infestation and mold growth.
   

• Remove all residual dockage and clean the bins before putting new crops in them, to avoid insect infestations.  
   

• Remove grain spills around bins. By cleaning the areas surrounding the bins, you remove weeds and grain residues where pests can develop.

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• Grain elevators

• A great amount of dust accumulates in various locations in grain elevators. Make sure elevators and areas where dust accumulates are cleaned regularly. The accumulated dust provides food and nest sites for stored grain insects and can possibly trigger a dust explosion.

• Augers

• Clean augers using a broom, air hose, or flush it to remove residual grain and foreign material.

• Dryers

• Clean dryer interiors with a brush, metal scraper, vacuum and/or air hose. Dryers can also be cleaned by opening the bottom and letting grain residue fall out, as long as all residue where insects and mold can grow are removed.

General guidelines for wet cleaning sanitation

• If wet cleaning is necessary, keep the amount of water used to a minimum. Ensure that all water and steam are contained within the immediate area.
   

• After wet cleaning, completely dry machinery, equipment and tools that are in contact with grains.

Benefits of following a housekeeping program include: reduced insect infestation and mold, improved aeration and air quality in grain processing areas and cleaner, safer grain.

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For information on the Food Safety Program contact the CVO/Food Safety Knowledge Centre.  For technical information, call 204-795-7968 in Winnipeg; or e-mail foodsafety@gov.mb.ca. For general information, contact your local GO Centre.