Food processing equipment can get dirty during production, and even the tiniest splatter of spilled ingredients can leave a biofilm that pathogens will love to colonize. For machines on the production floor that are too large to move, you’ll need to do a washdown in place.

Washdown procedures help sanitize food equipment by removing organic matter residue that can harbor dangerous bacteria. In order for the washdown program to be effective, however, it must be thoughtfully designed.

From selecting production components to coordinating sanitation schedules, every element of your washdown procedure needs to be carefully considered. When developing a washdown procedure, start with the basics and have a plan to avoid the common pitfalls.

Part of the Plan

The Food Safety Modernization Act requires a proactive approach to controlling contamination hazards before they become an issue, so a washdown procedure needs to be part of your facility’s Food Safety Plan. Your washdown protocol needs to be in place—complete with thorough documentation and lab-based verification—before a contamination hazard arises.

The washdown process should be both routinely scheduled and triggered by unexpected events. Your plan should include a calendar for regular washdowns, and a washdown should automatically follow events that leave machinery unusually dirty, such as ingredient spills or equipment malfunctions.

Staff for Success

Like every element of your Food Safety Plan, washdown procedures will ultimately fall under the authority of the facility’s Qualified Individual. The QI will need to put together a sanitation team with the expertise to make sure the job’s done right: you’ll want workers with a background in sanitation and safety, but you’ll also need crew members who understand the maintenance needs of the machinery, as well as teammates watching for quality control issues. The sanitation team will require annual training, with supplementary education any time the line machinery is updated.

Equipment To Make It Easy

Well-designed equipment can make the washdown process go smoothly. Hygienically designed production equipment built to the 3A, EHEDG, or AMI specifications will be designed for easy cleaning, with an absolute minimum of crevices where biofilms can hide and mirror-smooth surfaces that are hard for bacteria to colonize.

The materials matter too: 316 stainless steel is the gold standard for sanitation—it has a far smoother finish than copper, and cleaning agents won’t oxidize it like aluminium. For components that can’t be made from stainless steel, synthetic polymers offer a strong combination of corrosion-resistance and impermeability.

The IP ratings of electrical components will tell you the switch or sensor’s water resistance. IP 67-rated components are waterproof, but an IP 69K rating indicates the component will stand up to high-pressure, high-temperature sprays. Remember, your machinery is only as durable as the weakest component—so if your washdown relies on streams of scalding hot water, make sure you select components that are similarly rated to withstand it.

Stages of the Washdown

The washdown procedure can be broken down into six basic stages:

• Prewash: A prewash to remove caked-on grime will prepare the surface for sanitation. The prewash should remove all visible soiling from the machine, leaving only thin biofilms that can be broken down by detergent in the next step.
• Soak: Next, the machinery is sprayed from top to bottom with a foaming detergent, coating every surface in a solution that will dissolve oil and sugar residues.
• Scrub: Mechanical action is necessary to ensure the removal of all traces of organic matter. Soft-bristled brushes are gentle on equipment and can squeeze into tight corners, but stiffer brushes may do a better job of removing stubborn materials.
• Sanitize: The cleaned surface is now ready for a sanitizing agent, which will kill any lingering pathogens. Many quat-based sanitizers are designed to be “no-rinse,” and can be left to dry on the equipment.
• Dry: Pockets of moisture are not compatible with a sanitary environment. Bacteria thrive in puddles and pools, so your washdown should conclude with the equipment in a fully dried state.
• Verify: Finally, you will need to verify that the washdown has successfully removed all traces of food residue. Whenever possible, visual inspection should be complemented with an ATP laboratory test, which will verify that no organic material remains on the machine’s surface.

Dodging Washdown’s Pitfalls

Improper washdown procedures can actually create new contamination hazards. When planning your washdown, watch out for the following pitfalls:

• Equipment Fatigue: Cleaning agents and mechanical scrubbing will gradually wear down production equipment, creating permeable surfaces that are impossible to thoroughly clean. Look for scratches, pitting and discoloration, all of which can indicate the formation of crevices where bacteria can hide.
• Turning to Scouring Pads: It’s tempting to use scouring pads to mechanically remove grime. Unfortunately, the pads’ fibers shred at a microscopic level as they clean, which introduces specks of foreign material into production equipment.
• Cranking Up the Pressure: A high-pressure spray will quickly blast off food residue, but an intense spray can splatter—and even aerosolize—harmful bacteria like listeria. The droplets from a high pressure spray can then condense onto equipment that has already been sanitized. This is why you should always use the lowest pressure possible in your washdown.
• Dry Detergent: Detergent only works when it’s wet, so you need to be careful not to allow foaming agents to dry. A dried detergent can form a soap film that retains organic matter, creating a contamination hazard.
• Leaks and Pools: The fittings and couplings on washdown hoses can drip, leaving pools of water and an unhygienic floor. Watch carefully for drips, and be sure your post-washdown inspection includes checking underneath machinery for pooled water.

Carefully consider every element of your washdown procedure. If you start with the basics and stick to a plan, you can avoid the common pitfalls.