9 min readPathway sheetOften a 10-mark answer; cleaning vs sanitising is a favourite 2-mark question

Cleaning compounds and sanitation methods

Clean first, then sanitise: detergents remove dirt and grease, then heat or chemicals such as chlorine, iodophors and QACs cut germs to safe levels.

CleaningRemoves visible dirt, food residue and grease

SanitisingReduces germs on a clean surface to a safe level

Chlorine sanitiserUsually 50-200 ppm for food-contact surfaces; follow the label

OrderScrape → wash → rinse → sanitise → air-dry

Cleaning, sanitising, disinfection and sterilisation

CleaningRemoves visible soil (food bits, grease, dust, scale) with water, a cleaning compound and scrubbing. A surface can look clean and still carry germs.

SanitisingReduces the number of microorganisms on a cleaned food-contact surface to a safe level, using heat or an approved chemical. Used on boards, utensils, slicers and tables.

DisinfectionDestroys most disease-causing microbes, usually with stronger chemicals, on non-food-contact areas such as toilets, drains, floors and bins. Spores may survive.

SterilisationDestroys all microorganisms, including spores, e.g. retorting cans or autoclaving. Not used for daily kitchen cleaning.

Sanitisers do not work on dirty surfaces, because food residue uses up the chemical and shields the germs. Always clean before you sanitise.

Cleaning compounds

Type	Examples	What it removes	Points to note
Alkaline cleaners	Strong: caustic soda (sodium hydroxide). Milder: washing soda (sodium carbonate), sodium metasilicate, trisodium phosphate	Fat, oil, grease and protein soil (ovens, tandoors, fryers, meat tables)	Strong alkalis burn skin and eyes; wear gloves and goggles; they can corrode aluminium
Acid cleaners	Strong: phosphoric, nitric acid. Mild: citric, acetic (vinegar), gluconic acid; tamarind on brass is a household acid cleaner	Mineral deposits: hard-water scale, milkstone on dairy equipment, rust	Corrosive; never mix with chlorine bleach, which releases toxic chlorine gas
Detergents (surfactants)	Synthetic detergents in dishwash liquids and powders; soaps	Lower surface tension, wet the soil, emulsify grease and hold dirt in the water so it rinses away	Soaps form scum in hard water; most detergents contain water softeners (builders)
Abrasive cleaners	Scouring powder, scrub pads, steel wool	Stubborn, dried or burnt-on soil	Can scratch surfaces where germs then hide; loose steel-wool strands become a physical hazard; avoid on non-stick and soft metals

Sanitisers

Sanitiser	How it is used	Advantages	Limitations
Heat: hot water or steam	Immersion in hot water at about 77 °C for at least 30 seconds (a common standard); dishwashers use a hotter final rinse; steam for large equipment	No chemical residue; cheap; reaches cracks	Fuel cost; risk of burns; the right temperature must be reached and held
Chlorine (sodium hypochlorite, bleaching powder)	Usually 50-200 ppm for food-contact surfaces, for the contact time on the label; made fresh	Cheap, fast, kills a wide range of microbes	Corrodes metals; irritates skin; weakened by food residue, heat, sunlight and standing
Iodophors (iodine with a detergent carrier)	Diluted to label strength; the amber colour shows it is active	Less irritating than plain iodine; colour shows strength; less affected by hard water	Stains plastics and some surfaces; works best in warm, not hot, water; costlier
Quaternary ammonium compounds (QACs), e.g. benzalkonium chloride	Diluted to label strength; sprays and wipes for surfaces	Odourless, non-corrosive, stable; leave a film that keeps acting	Inactivated by soap and hard water; weaker against some bacteria and spores
Others: hydrogen peroxide, peracetic acid, ozone, UV light	Mainly in food factories and for packaging	Leave little residue	Need special equipment and trained staff

The cleaning procedure (the order never changes)

Small items are washed by hand in a three-compartment sink (wash, rinse, sanitise) or in a dishwashing machine. Pipes and tanks in dairies and beverage plants are cleaned by clean-in-place (CIP): the same solutions are pumped through without taking the plant apart. Follow the chemical label for strength and contact time.

1
Prepare: switch off and unplug equipment; take apart removable parts; wear gloves (and goggles for strong chemicals).
2
Pre-clean: scrape or wipe off loose food and pre-rinse.
3
Wash: scrub with warm water and detergent.
alkaline for grease, acid for scale
4
Rinse with clean water to remove detergent and loosened soil.
5★
Sanitise with hot water or a chemical sanitiser at the right strength, for the full contact time.
6
Air-dry on a clean rack.
do not wipe with a cloth
7
Store covered, put equipment back together, and sign the cleaning record.

★ one-way, controls the pace

Activity: work instructions for sanitation and cleaning staff

A work instruction is a short, step-by-step card displayed where the job is done. Write it in simple words, in the staff's own language, with pictures if possible. Example: cleaning and sanitising the vegetable-cutting table and chopping boards at the end of each shift.

1
Heading: title of the task, area (vegetable section), frequency (end of every shift), person responsible and the supervisor who checks.
2
Materials and protective wear: detergent, sanitiser with its dilution chart, colour-coded brush and cloths, bucket, gloves, apron, goggles for strong chemicals.
3
Prepare: remove food and waste; put boards and knives in the sink; make the sanitiser solution fresh, exactly as the dilution chart says.
4
Clean: scrape, wash with detergent and hot water, scrub corners, edges and knife marks, then rinse.
5
Sanitise: wipe or spray the table and dip the boards in sanitiser for the contact time on the label; stand boards upright on a rack to air-dry.
6★
Safety: never mix bleach with acid cleaners or ammonia; keep every chemical labelled in its own container, away from food.
7
Check and record: the supervisor checks visually (and with swab tests where available); staff sign the cleaning log and report deeply scored boards for replacement.

★ one-way, controls the pace

In kitchens and food businesses

A hotel or hospital kitchen keeps a master cleaning schedule (what, when, who, which chemical, how) and a dilution chart beside the sink. Colour-coded boards and cloths, for example red for raw meat and green for vegetables, stop cross-contamination.

Exam angle

2 marks: “Differentiate cleaning and sanitising.” Cleaning removes visible soil with detergent and water; sanitising reduces microbes on the cleaned surface to a safe level with heat or chemicals. Clean first, then sanitise.

5 marks: “Write short notes on chemical sanitisers used in the food industry.” Chlorine, iodophors and QACs (plus peracetic acid): how each is used, two advantages and two limitations each; heat as the non-chemical option; follow the label.

10 marks: “Describe the cleaning compounds and sanitation methods used in food establishments.” Define the four terms; table of cleaning compounds (alkaline, acid, detergents, abrasives); sanitisers (heat, chlorine, iodophors, QACs); cleaning steps; methods (three-compartment sink, machine, CIP); safety; master cleaning schedule.

Remember it

Cleaning order is S-W-R-S-D: Scrape, Wash, Rinse, Sanitise, Dry (air-dry). Cleaning power is TACT: Time, Action (scrubbing), Concentration, Temperature.