Presco Environmental technician, Jeremy, cleaning the soil from louvres (9,680 of them!) before he can sanitise.  

You Can't Sanitise Dirt: 7 steps to clean

Saskia Prestidge
April 27, 2020

That’s right, you need to use that ‘C’ word first, sorry!

For thorough sanitising in the food industry, the key (and hopefully not overlooked) step is pre-cleaning. Clean first. Sanitise afterwards. In that order. Always. No exceptions. Period. To head off any potential disagreement or passive aggressive protest, let’s boil each step down to its most basic function.

Cleaning: removal of visible soil (food, dirt, dust, grease, stains) and odours from a surface.
Sanitising: killing of microscopic pathogens on a surface.

There are 7 key steps that need to be incorporated in a cleaning and sanitising program, if sanitising is to be effective:

1. Pre-clean

  • Like many things in life, the outcome is largely dependent on the preparation put in. So here it is, the more effort you put into this step, the better the outcome from all other steps!
  • Remove as much soil as possible before hitting anything with water. (Water is a solvent and spreads what was solid soil out into a dirty liquid over a much wider area. Don’t make life any harder for yourself than it needs to be!)
  • Removal methods commonly include: scrape, brush, sweep and vacuum clean. (Please don’t blow down with compressed air, you’ll contaminate every hard -to-reach high surface and ledge in the room!
  • Recover/contain this soil and dispose of it

2. Apply chemical or detergent

  • Once the bulk of soil accumulation has been removed, its time to tackle the stubborn and hard to reach nasties that remain.
  • An approved detergent will break down the remaining soil and contain ‘surfactants’ that help the soil release and move/flow away much more effectively.
  • Use the detergent at the manufacturers suggested dilution rate. Don’t mix up more than you need for each time.
  • Let the detergent dwell for the time recommended by the manufacturer. Ensure it does not dry out in this time, re-apply if it does. (Trust me, this is where you’ll save some sweat and tears. This step saves a lot of elbow grease, let the chemical do its job by not rushing it.)

3. Wash off with hot water

  • Hot water helps dissolve fats and greases and generally cleans much better than cold water. It also speeds up dry time. (just need to ensure your ventilation system remains on to prevent the room steaming up.)
  • Moderate pressure adds a beneficial ‘mechanical’ action to washing. Use of an adjustable nozzle to increase tip pressure or a moderate electric pressure washer system is preferable.
  • Avoid the washing water running down over chemical on an unwashed surface. The best effect is when the water is hitting a surface that still has chemical soaking on it. This means starting at the bottom and washing up (counter-intuitive though it may first appear. Don’t worry, this is all sorted out in the rinse step next.)
  • Avoid splashing dirty wash water over cleaned surfaces, plan your clean and regularly rinse your wash area to keep bringing all soil with you.

4. Rinse down

  • Start at furthest point away from the floor drain and start high. Clean down and towards drains always moving away from the rinsed clean areas
  • Avoid contaminating cleaned surface with rinse water splashes.
  • Clean any debris out of all floor drain filters after rinse down.
  • Be thorough, don’t rush this step.

5. Sanitise

NOW its time to sanitise.

  • Mix sanitiser to the manufacturer’s recommendations (stronger, is not necessarily better) each use to keep it fresh and effective and use it all up.
  • Apply sanitiser as a fine spray mist. To get the best effect use a thermal fogger, Ultra-Low Volume (ULV) mister or electro-static sprayer to get the sanitiser into every nook and cranny.
  • Pay attention to required dwell time on the sanitiser manufacturers label. (Often minimum of 30 seconds) Ensure surfaces stay wet during this time, re-apply if necessary.

Note: temperature can be used in place of or as well as sanitiser chemical.

6. Post-sanitiser rinse 

Rinse down food contact surfaces, if required, after the sanitiser has had correct dwell time (as per chemical manufacturer, government body requirements.) If possible, use a non-rinse food grade sanitiser to void this step.

7. Dry

  • Air dry is best, (wiping down can re-contaminate surfaces.)
  • Surfaces need to be completely dry again before being used for food processing

And there you have it, not so bad now was it? Just remember, jumping straight to step 5 is a waste of time and chemical. You can’t sanitise dirt!

  • (Anyone from the USA has permission to substitute ‘sanitize’ for ‘sanitise’ wherever it appears in this article, either works, as long as you have CLEANED first! 😁) 

Bonus tip:

Remember the cleaning acronym; clean using TACT. To get a better cleaning effect, you need to increase one or more of these four cleaning factors.

T = Temperature. Usually refers to using hot water. (Can include cold – google Dry Ice Blasting)
A = Action. Mechanical or manual cleaning actions (scrub, scrape, pressure wash)
C = Chemical. An appropriate chemical to soften and move the target soil.
T = Time. Covers both dwell time for chemical and time allowed for the cleaning task in general

Ref: Standard 3.2.2 Food Safety Practises and General Requirements