Washdown Safety Standards: Cleaning Without Ruining Electronics

A costly misconception is that stainless-steel construction makes a commercial food machine waterproof. While stainless steel provides good durability and corrosion resistance, it is not immune to scratching, chemical attack, or pitting. The internal components remain vulnerable to water ingress. Aggressive or improper washdown practices are a primary driver of premature equipment degradation.

Incorrect washdown practices can result in water ingress, corrosion, electrical faults, damaged bearings, unplanned downtime, and food-hygiene failures.

What Is the Difference Between Cleaning, Disinfection and Washdown?

To establish a safe hygiene routine, you must distinguish the cleaning process:

• Cleaning: Removing food deposits, grease, dirt, films, and allergen-containing residue from a surface.
• Disinfection: Reducing microorganisms on an already clean surface to an acceptable level using chemicals or heat.
• Rinsing: The removal of residues using clean water.
• Washdown: Cleaning equipment with water, usually alongside detergents or disinfectants.
• Dry Cleaning: Removing dry soils, dust, or powders without water by using scrapers, vacuums, or cloths.

Disinfection is not a substitute for cleaning. Food deposits can prevent a disinfectant from reaching the underlying surface and can reduce its effectiveness.

When selecting a food-surface disinfectant, check that it is suitable and follow its dilution, temperature, and contact-time instructions. The Food Standards Agency recommends checking product labels for standards such as BS EN 1276 or BS EN 13697.

Which Rules and Standards Apply?

Safe washdown is governed by several overlapping requirements:

• Food Hygiene: All food-contact surfaces and machinery must be cleaned and disinfected frequently to prevent cross-contamination.
• PUWER (Provision and Use of Work Equipment Regulations 1998): Requires work equipment to remain safe, suitable and properly maintained. Cleaning is included within the regulations’ broad definition of equipment use.
• Electricity at Work Regulations 1989:Electrical systems must be constructed and maintained to prevent danger.
• COSHH (Control of Substances Hazardous to Health): Employers must assess and control exposure to cleaning chemicals that are hazardous to health.
• Manufacturer Operating Instructions: These establish the approved cleaning method, permitted disassembly, chemical restrictions, and any pressure or temperature limits.
• Ingress Protection/IP Codes: IP ratings classify the protection an electrical enclosure provides against access, solid objects, and water ingress.

Different Cleaning Methods

As a general framework, commercial food equipment can be divided into four broad cleaning categories. These are not formal legal classifications.

Dry-cleaning is usually required for retail weighing scales, electronic labelling units, and other equipment that has sensitive electronics. Do not directly spray water on these products. Instead, use a vacuum, brush, scraper, or damp cloth.

Manual damp cleaning is used on most table-top appliances such as meat slicers, blenders, and vacuum packers. To do so safely, turn off the power, remove components to wash separately in the sink, and wipe down the body of the machine with a damp cloth.

Low-pressure washdowns are used on the majority of heavy-duty equipment such as bandsaws, sausage fillers, and meat mincers. A low-pressure hose uses water on specific areas of the machine, staying clear of the controls.

Full wet washdowns are only suitable for industrial processing lines, carcass washers, and inline tray sealers. Always consult the manufacturer’s guidance for water pressure, temperature, spray distance, and chemical limits.

Frequently applying a pressure washer directly to equipment causes mechanical and electrical damage such as seal displacement, bearing contamination, thermal vacuum ingress, cable gland ingress, and invisible corrosion traps. Never use a high-pressure washer on commercial food machinery unless the manufacturer explicitly permits it in the user manual and specifies the water pressure, temperature, nozzle distance, and spray zones.

Understanding IP Ratings

IP stands for Ingress Protection. Ingress is the act of entering something, which, in this case, outlines moisture and contaminants entering the electrical components. IP ratings are not a measurement of how "waterproof" a machine is, or proof of chemical, steam, or thermal shock resistance.

An IP rating normally contains two numbers. Each number describes a different type of protection. The first number relates to protection against access to hazardous parts and the ingress of solid foreign objects, while the second number relates to protection against harmful water ingress.

A Safe Cleaning Procedure

Before applying water or cleaning solutions to food processing equipment, staff must isolate all energy sources. Follow this hygiene process to safely clean commercial machinery:

Step 1: Remove Food Residue

Use a plastic scraper or brush to remove food residue, fat, and other debris. Avoid carbon-steel tools or wire wool, as these can scratch the surface and create rust staining.

Step 2: Dismantle Removable Components

Strip removable parts. Do not place sharp blades loose in the sink.

Step 3: Clean Removable Parts Separately

Clean removable food-contact components using detergent and following the required concentration, temperature, and contact time. Do not immerse electrical or motorised attachments.

Step 4: Clean the Fixed Machine Body

Wipe or wash down the machine body using the lowest water pressure necessary. When applying low-pressure spray, direct the water stream away from sensitive areas:

• Electric motors and cooling fan cowls.
• Digital control panels, touchscreens, and membrane keypads.
• Push-button stations and emergency stop switches.
• Cable entry glands and flexible conduit fittings.
• Shaft seals and main drive bearing housings.
• Electrical enclosure door seams and latch points.

Step 5: Rinse

Follow the cleaning product’s instructions. Some chemicals must be rinsed from food-contact surfaces, while others may be specified as no-rinse. Do not assume that every product is the same.

Step 6: Apply Food-Area Disinfectant

Apply a disinfectant at the correct dilution rate. Allow the chemical to remain for the required contact time.

Step 7: Drain and Air-Dry

Remove standing water and allow parts to drain and air-dry. Do not use high-pressure compressed air to dry food machinery. It can spread contamination and force moisture into seals and inaccessible areas.

Step 8: Inspect and Reassemble

Inspect cleaned surfaces for residues or films and reinstall dry components and safety guards, verifying that all seals and mechanical latches are correctly placed.

Step 9: Verify and Release

Complete the cleaning record and carry out any pre-start checks. Reconnect the power only when the machine is dry, correctly assembled, and safe.

Choosing Chemicals That Will Not Damage Stainless Steel

Stainless steel maintains its bright, corrosion-resistant surface from a Chromium Oxide passive film. Certain chemicals and conditions can locally damage this protection and cause staining or pitting.

Chemical To Avoid

• Bleach: High concentrations of chlorine bleach or chloride-based cleaners attack chromium oxide, causing deep "pitting corrosion" on stainless steel.
• Hydrochloric Acid: Extremely destructive to stainless alloys; should never enter a food processing environment.
• High Chemical Concentrations: Over-dosing detergents accelerates the degradation of rubber door gaskets, flexible cables, and clear plastic viewing panels.
• Extended Contact Times: Allowing chemical foam or sanitisers to dry on stainless surfaces concentrates active salts, leaving permanent water marks and surface pitting.
• Incompatible Cleaning Tools: Using carbon-steel wire brushes, metal scouring pads, or steel scrapers embeds iron particles into the steel, creating rust spots.

Under the Control of Substances Hazardous to Health (COSHH) Regulations, food business operators must assess the health risks associated with cleaning chemicals before use. A Safety Data Sheet provides important information, but it is not itself a COSHH assessment. HSE provides specific guidance on disinfectants in the food industry and chemical safety data sheets.

Buying Machinery for a Wet-Cleaning Environment

If your processing facility relies on daily wet washdown cleaning, you must take extra care when investing in new equipment. Ensure that you have checked the manufacturer’s manual and IP ratings for cleaning specifications. Also consider any warranty terms that state that water-ingress damage is not covered.

Protect Your Investment

Effective equipment cleaning must remove food residue and contamination without introducing electrical, chemical, or mechanical hazards.

The safest approach is to follow a machine-specific cleaning procedure, isolate the equipment correctly, use compatible chemicals, and inspect the machine before it returns to service.

SMS Food supports UK food businesses with commercial machinery, manuals, genuine replacement parts and servicing expertise. If you need model-specific cleaning information, consult our manuals and documentation, browse our spare parts, or arrange equipment servicing.

For further assistance, call 01625 827 827 or use our contact page.