Food Communication Bulletin, Issue 31: Cleaning and Sanitising of Mechanical Equipment
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Legislation requires food premises including fixtures, fittings and equipment to be kept clean. Utensils, equipment and surfaces that come in contact with food must also be sanitised. This may include equipment used to clean food contact surfaces, for example cleaning cloths.
Cleaning is the process of using a detergent and water to remove residual food matter, visible dust, grease, dirt, stains and odours from all surfaces, fixtures, utensils and equipment.
Sanitising is the process of killing food poisoning bacteria (what you cannot see) and is achieved by using heat and/or chemicals. This process should reduce the number of microorganisms to a level that does not compromise the safety of food with which it may contact and does not permit the transmission of infectious disease.
It is important to know the general categories of chemical types to ensure you are using the appropriate one.
Detergents are soap in liquid form. They attract and wash away grease, dirt and debris from surfaces. They do not kill bacteria.
Sanitisers are chemicals that are capable of destroying microorganisms including food poisoning and other disease-causing bacteria. When manufacturer’s instructions are followed, they can reduce surface contamination by bacteria to a safe level.
Disinfectants are commonly household cleaning products suitable for toilets and floors but not always for food contact surfaces. They generally contain deodorants. They must not be used as sanitisers for food contact surfaces (unless advised by the manufacturer that it is safe and suitable to do so).
Sanitising is not a substitute for cleaning and is most effective at killing food poisoning bacteria when performed after cleaning. The two most commonly used methods of sanitising are heat and chemicals, or a combination of both.
Hot water must reach a minimum of 77oC for at least 30 seconds to be effective. A heating element should be used to keep the water temperature at 77oC or higher. Water at this temperature can be dangerous, so this method is recommended for use with specialised equipment such as dishwashers or other processing equipment with cleaning-in-place technology.
It is important to note that there is a difference between how commercial dishwashers and domestic dishwashers work. In general, commercial dishwashers use high water temperatures (above 80oC) whilst domestic dishwashers use a lower temperature (around 65 to 68oC). Since domestic dishwashers operate at lower temperatures, it is important that the longest cycle time and hottest temperature setting should be used for effective sanitation to occur.
It is the businesses’ responsibility to ensure the dishwasher used is effectively sanitising. To demonstrate this, businesses may require technical specifications for the specific dishwasher model they are using. For further information, refer to Safe Food Australia, Appendix 4.
Tips for effectively sanitising with a dishwasher:
Chemical sanitisers are also an effective way to sanitise. Some dishwashers are designed to also use chemicals to sanitise. Food businesses must ensure that any chemical sanitiser used is “food grade”, as specified by labelling and material safety data sheets, and that it is used and stored in a manner that will not contaminate food. Food grade indicates that it is safe for food contact surfaces. When using chemical sanitisers, it is important to always refer to the manufacturer’s instructions.
When sanitising manually, the following methods can be used:
In both instances, allow sufficient time for the sanitiser to work and then allow to air dry or wipe off with a clean sponge, cloth or single-use paper towel.
Commercial sanitisers are available from a range of commercial chemical suppliers and retailers. The most commonly used sanitisers used in food businesses contain chlorine or quaternary ammonium compounds (QUATs) as active ingredients. These must be used in accordance with the manufacturer’s instructions. It is also important to check that the sanitiser you use is food grade along with any other information on its effectiveness in sanitising and ensuring it does not inadvertently contaminate food.
Bleach is an inexpensive chemical that can be used to sanitise. Only plain, unscented bleach should be used and generally range from 4% to 10% chlorine (the active ingredient) as indicated on the label. Diluted bleach solutions (see below) should be made up every 24 hours as the chemical breaks down and becomes ineffective after this time. Contact time may vary between brands but 10 minutes is a good rule of thumb. Utensils, equipment and surfaces can be left to air dry (no rinsing required) unless stronger concentrations than recommended are used.
Other chemical sanitisers include organic sanitisers and combined detergent-sanitiser chemicals. Sanitisers with peracetic acid, hydrogen peroxide or organic acids as active ingredients are examples of organic sanitiser and must be used in accordance with the manufacturer’s instructions. Specially designed detergent-sanitiser chemicals may be appropriate for some small businesses with limited sanitation requirements and a single bowl sink. These must be used in accordance with the manufacturer’s instructions and should be effective on lightly soiled surfaces with no protein or fat residues.
Other alternatives such as vinegar, lemon juice and methylated spirits should not be used as sanitisers. Vinegar and lemon juice are weak acids and not effective at sanitising. Methylated spirits can leave chemical residues on surfaces which may taint food rendering it unsuitable. Citrus based cleaners are not proven to have a sanitising effect and should only be used as cleaning agents.
Sometimes, mechanical equipment can look clean on the outside but may be dirty on the inside. Mechanical action may draw food and bacteria into the inside areas of equipment where bacteria can grow, multiply and then contaminate the next food that is prepared with the equipment.
So it is important that all equipment can be dismantled enough for it to be thoroughly cleaned and sanitised.
See the Cleaning and sanitising – mechanical equipment fact sheet (PDF 115KB) for more information on how to effectively clean and sanitise mechanical equipment.