Cleaning and sanitization of Milk Cans and Tankers

Cleaning is done to remove the residues of milk from the surface of the utensils,while sanitization is done to destroy all types of micro-organisms present on the surface of the utensils and equipments.

 

i. Types of Washers:

The types of washers include manual washing, mechanical washing and cleaning-in place.

(i) Manual washing: Small plants are not equipped with mechanical can washers and employ manual washing methods. Manual washing can be aided by installation of can washing trough, can scrubber, and can rinsing and steaming block. These tools will be helpful in reducing the manual brushing, rinsing and sanitizing the cans.

(ii) Mechanical washer: In mechanical washing, the can is usually passed over a succession of jets emitting water, cleaning solution, hot water, steam and air. Where the operation is big and manual washing is considered difficult and uneconomical, washing is done mechanically. Mechanical can washers are of two types:

a) Rotary type: One man is required to place the cans and lids in inverted position in the machine and remove them after washing and drying. The can and lid are moved through a rotating platform divided into sections.A series of tanks of solutions are located under the platform. Cans get continuous spray of various solutions both inside and outside through circulating pumps and solutions return to respective tanks. The rotary washer rotates at intervals.

b) Straight through or tunnel type: In this type, empty can and lid in inverted position enter into the tunnel at one end of the conveyor and come out at the other end after getting cleaned, rinsed, sterilized and dried in straight-up position. The main operations involved are: pre-rinsing with clean water, steam sterilization, detergent solution washing,hot water rinsing and hot air drying. All these operations are carried out in quick succession and the process is continuous.

(iii)Cleaning-in-place: The permanent line as well as equipment remain intact during the cleaning and sterilizing procedures. Milk tankers can be cleaned by this method. The modern dairies are equipped with CIP system of cleaning which is controlled by electronic device. The cleaning operations are programmed according to the need and the operations have to make necessary connection for the proper flow of liquids. The CIP system consists of essentially 3 tanks, namely cold water, hot water and detergent or lye tank, and an automatic electronically controlled panel. The route sequence selection may be manual, semi or fully automatic. The sequences are programmed operations controlled by card, tape or microprocessor.

 

ii. Sanitizing Systems

 Cleaning is followed by sanitizing. Sanitizing is done chemically or by hot water or steam to kill pathogenic organisms and nearly all non-pathogenic organisms. Dairy equipment can be sanitized with application of one of the following methods:

•  Flushing: All equipment and piping are assembled and flushed out with a hypochlorite solution.
• Spraying and brushing of equipment.
•  Fogging: sanitizing solutions may also be applied by air pressure or atomizing solution in form of a mist or fog. The minimum chlorine strength should be 400 ppm and the strength at the discharge end around 100 ppm. To avoid corrosion,the chlorine should not stand in the tank longer than 30 minutes.
•  Submersion: Small parts, pails and certain utensils may best be sanitized by submersion in a sanitizing solution.