Manual cleaning has in many instances become unrealistic and uneconomic due to the high volume of items required by modern businesses with, for example, a large bakery requiring 2,500 baskets an hour to keep production flow on track.
Washing machines come in a variety of forms, generally being built for the cleaning of a specific type of item and it is important that they are used only for this intended purpose.
These machines must looked after and maintained with; regular cleaning including the filters, the changing of the wash solutions, the inspection of rinse nozzles and control & monitoring of detergent temperatures and strengths.
All washing machines are either tunnel type or single tank machines.
Items are placed on a conveyor which transports them through the various stages of the washing process, with each stage occurring in a different section of the washer; pre-rinse, wash with detergent, rinse, disinfect chemically or by temperature and then dry.
With single tank machines the item is placed in a cabinet and the wash process takes place in the cabinet by sequencing the cleaning stages: prerinse, wash, rinse and disinfect.
The detergent is commonly a low foaming detergent appropriate to the equipment being cleaned and the nature of the soiling, Caustic based detergents are usually the most efficient and cost effective types of detergents used for this method of cleaning. A chlorinated detergent must not be used above 55C as it can attack stainless steel. A neutral or inhibited detergent may be employed for cleaning of sensitive items, such as aluminium trays.
Carried out with water fed directly from a heat exchanger or from a separate enclosed non-recirculating tank and where rinsing is not followed by a final disinfection stage, the rinse water should be maintained at a minimum of 82C. Attention must be paid in hard water areas, as there could be a significant problem of scale drop out and so the relevant machine must be regularly de-scaled.
Certain cleaning solutions are reused such as detergents, and when these become contaminated with soil from washed items this becomes a way for allergens to transfer, making validation of the washing process being carried out vital.