dish washing

Practical 10

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Dish Washing

 The object of dish washing or cleaning utensils is to remove any dirty material from them on which micro-organisms can develop, and to destroy any micro-organism which are already present in the service ware by sterilizing.

Usually dishwashing is of two types 

1.      Manual Dishwashing

2.      Mechanical Dishwashin

· Manual Method: Dishwashing by hand can be done by the two-sink method or by the three sink method. Both these systems start with the removal of leftover food, followed by a preliminary wash under running hot water, which helps to preserve the cleanliness. The dirt is removed from the utensils by scraping and then rinsing under the forced water stream. 

Two - Sink Method: The simplest way of having germ-free cutlery and utensils is the two-sink method. Washing and rinsing of service ware is done in the first sink that contains hot water at 45degreeC. Rinsed service ware is then sanitized in the second sink containing hot water at 770C and above with sanitising solution. 

Three - Sink Method: After the dishes have been sorted out and the debris has been· removed, the utensils are washed in warm detergent solution in the first compartment, and then rinsed in second compartment at the temperature of 450C. Service ware is then transferred to third sink for sanitization at 77degreeC and above.

The other method of sterilizing service equipment is treating them with a chemical solution prepared with lukewarm water and chlorine or iodine solution or tablets.

https://www.youtube.com/watch?v=bpp1Syx0xec

 Machine Method After removing the debris, the plates are stacked into wooden or wire racks and then are passed through the dishwashing machine. The chinaware is washed, rinsed and sterilized in the washing machine. After passing through the machine, the china is left to drain for two to three minutes and is then stacked on respective shelves. The dish wash machine usually consists of a conveyor belt that assists in transporting the tableware through the machine.

In the dish washing machine, washing happens in four stages – pre wash stage, wash stage, pre rinse stage and final rinse.

In pre-wash chamber, sprays of hot water re-circulated by the pump, removes most of soil from the dishes.

. In the wash stage, the dishes are washed with detergent solution. Here, all the soil and stains are completely removed. The conveyor then passes through the pre-rinse stage, where hot water is sprayed to remove most of the washing solution. In the final rinse stage, the dishes are rinsed with hot water to remove any of the detergent that is remaining. The water at this stage is hot enough to act as a sanitizer.

A rinse additive is injected into the final rinse water to provide a sheeting effect for quick drying and to prevent water spotting