Understanding Contact Times for Kitchen Surface Sanitisers

What Contact Time Actually Means

Every kitchen sanitiser carries a contact time on its label, sometimes called dwell time. It is the length of time the diluted product must stay visibly wet on the surface for it to achieve the kill rate it claims. It is not the time it takes you to spray, and it is not the few seconds before you reach for a cloth.

It helps to separate cleaning from sanitising. Cleaning removes grease, food debris and the film that microbes hide in. Sanitising reduces the number of microorganisms left behind to a safe level. If you sanitise a dirty surface, the sanitiser is used up on the soil instead of the microbes, and the contact time on the label no longer means anything.

Contact times vary widely between products. Some ready-to-use sprays work in thirty seconds, others ask for sixty seconds, and some concentrated dilutable products need two to five minutes. Always read the label for the product in your cupboard rather than assuming they are all the same.

Why It Matters in a Working Kitchen

A kitchen is a constant stream of interruptions. A quick spray and an immediate wipe feels thorough, but it may leave the surface no cleaner in microbiological terms than a plain soap-and-water wipe. The sanitiser simply has not had time to do its job.

The problem is worse on warm surfaces, near fryers, grills and ovens, where a fine mist can evaporate in seconds. Once the film dries, the active ingredient is no longer in solution and the clock stops. On a cold stainless steel prep bench in a cool room, the same product may stay wet comfortably for the full dwell time with no effort at all.

High-touch points deserve particular attention: fridge and cupboard handles, tap levers, bin lids, light switches, till areas and the edge of the prep bench where hands rest. These are touched dozens of times per shift and are often the last things anyone thinks to sanitise properly.

Getting the Dilution and the Surface Right

Concentrates are economical but unforgiving. Over-diluting gives you a weak solution that will not meet its stated contact time, while over-strengthening can leave residue, taint food and damage surfaces. Some actives also perform poorly in hard water, which is common across much of the UK.

• Measure with a proper jug or dosing pump, not by eye.
• Mix fresh solution for each shift; many diluted products lose potency within hours.
• Use the correct concentration for the job — food contact surfaces often differ from floors and drains.
• Check the label for the temperature range the contact time was tested at, usually around 20°C.
• Store diluted product in a clearly labelled bottle, never an unmarked spray.

How to Apply So the Surface Stays Wet

Work in manageable sections, roughly a square metre at a time, rather than spraying an entire kitchen and hoping. Apply enough product to leave a uniform wet film — a light mist that flashes off in five seconds is not enough.

• Clear the surface of food and loose debris first, then clean with detergent and rinse.
• Spray or apply directly to the surface, not onto a dry cloth, unless the label says otherwise.
• Start a timer or count deliberately. Thirty seconds of tidying elsewhere is not thirty seconds of contact.
• Re-wet any patch that dries before the time is up rather than restarting the whole surface.
• Wipe with a clean cloth once the dwell time is complete, and change cloths often.

A simple two-cloth method works well: one cloth for the detergent clean, a second, colour-coded cloth for the sanitising step. Never dip a soiled cloth back into your fresh sanitiser solution.

Rinsing and Food Contact Surfaces

Not every sanitiser needs rinsing, but many do. If a surface comes into direct contact with food — chopping boards, prep benches, utensils, worktops — check the label for whether a potable water rinse is required. No-rinse products are formulated to be left in place at the correct dilution; anything else should be rinsed and left to air dry where possible.

Air drying is worth building in. Wiping dry with a re-used tea towel can undo the work you have just done, and damp surfaces encourage bacterial growth between tasks.

Making It Work in a Busy Shift

Realistic routines beat perfect ones. Sanitise at the start of the day, at natural breaks, and at close. During service, keep a ready-to-use sanitiser and a clean cloth at the pass for quick turnarounds on boards and benches, and accept that a thirty-second product will be more useful at peak times than a five-minute one.

Train everyone on the same three facts: the correct dilution, the contact time, and whether the surface needs rinsing. Write them on a small laminated card by the sink. Note the products you use in your food safety management records, keep safety data sheets accessible, and review your routine when you change product — a new sanitiser often means a new contact time, and the old habits will not always fit.