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Current Category » Practicals on Technology of Milk & Milk Products

Use of Detergents and Sanitizers in Dairy Industry


1. To learn the use of detergents and sanitizers meant for the cleaning of Diary Utensils.
2. To study the scientific method of cleaning diary utensils.

Relevant information:

All the dairy utensils after use contain some milk which after drying forms a thin film which encourages the bacterial growth. This film or dried milk is difficult to clean and remove in order to produce milk with low bacterial content and high keeping quality, it is absolutely necessary to clean and sterilize the utensils. Milk readily absorbs taints from vessels which are not properly cleaned and sterilized. Unclean surface also causes biological fermentation which lowers the quality of milk. Milk often develops metallic taste from can surfaces which are not kept clean or are not coated properly with tin. Unclean cans cause unnecessary financial loss by reducing the keeping quality of milk.

Handle cans/utensils carefully to avoid damage to them and keep them clean. Use cans constructed of heavy gauge material so that they do not dent easily. Reject the utensils which have cracked or are pitted and rusty.

The operation of cleaning of the dairy utensils is achieved by employing detergents. The detergents are a substance which functions to remove milk deposits and other foreign matter from the surface to be cleaned. Many detergents however, combine the action with sterilizing action. For a substance to act effectively as detergent, it should have good wetting properties i.e. the ability to spread itself uniformly over the surface to be cleaned. Besides this it should have the following desirable properties.

A) Wetting and penetrating power
B) Emulsifying power
C) Saponifying power
D) Defloculating power
E) It should be completely and quickly soluble in water.
F) It should be non corrosive. Dairy detergents are broadly classified into four groups.

i) Alkali’s:

Sodium hydroxide, sodium carbonate, sodium phosphate.

ii) Acids:

Phosphoric, tartaric, citric acids are milk acids while strong acids like nitric acid is also used.

a) Polyphosphates or Chelating chemical:

These are used together with acids or alkalies. Tetra Phosphate, hexametra phosphate.

iii) Wetting agents:

These are either used alone or in conjunction with acids or alkalies e.g. teepol.

iv) Sanitizers:

Chemical substances which prevent growth of micro-organisms are known as antiseptics while those with cause death are called “disinfectant “,” germicide”, or “Sanitizer”. Sanitizers should have the following properties.
1. Quick acting.
2. Easily and quickly applied.
3. Relatively inexpensive.
4. Relatively non corrosive to hands and dairy utensils.

Method of washing:

i) Hand washing:
1. Thoroughly rinse the utensil with clean cold or luke warm water.
2. Introduce suitable detergent solution of 0.8 to 1 percent at 50 0 C temperature into the utensil. Thoroughly brush the surface with a clean brush.
3. Wash the utensil with enough fresh water using a clean brush to remove all traces of detergent.
4. Allow the utensil to drain thoroughly and let it dry.
5. Sanitize the equipment surface by steam or hot water after cleaning or by rinsing with chlorine solution just before using.


1. Follow the manufacturer instructions for specially coated surface equipments.
2. For general use employ correct strength of detergent or sanitizer solution.
3. Regular temperature conditions.
4. Ensure that utensils are cleaned prior to sterilization.
5. Avoid deposition of milk stone or other residue on the surface.
6. Preferably use seamless pails or utensils.
7. Use rubber glove to avoid skin injury from detergent action.

Material required / Apparatus:

1. Nylon brushes
2. Scraper
3. Water supply or hose connection
4. Heating source or boiler for steam
5. Soaking tank
6. Detergent mixture sanitizer unit
7. Racks for drying of utensils
8. Rubber hand gloves / gum boots for workers if possible.

Procedure for cleaning and sanitizing of dairy utensils:

1. Remove any residual loose milk or other solid material by rinsing the utensils with cold or luke warm water to remove as much milk residue and other material as possible.
2. After being rinsed and drained, the utensils should be brushed with a hot detergent solution (120 0 F) to remove any remaining from lids.
3. Rinse again with hot water to remove traces of detergents and any loose material.
4. Sanitize the utensils before use either by steam or chemicals to destroy all pathogens and almost all non-pathogenic organisms.
5. Drian the utensils to prevent further bacterial growth.
6. Dry the utensils by keeping it in inverted position.
7. Do not use a cloth or towel for drying.

Choice of detergents in organized dairies:

Sr. No.





Trisodium phosphate wetting agent

850 g

For general use



150 g



Trisodium phosphate sodium

650 g

For aluminium


Meta silicate

200 g



Wetting agent

150 g



Trisodium phosphate

750 g

For tinned Utensils


Sodium Sulphate

100 g



Wetting agent

150 g


(Wetting agents ------------------- Teepol, Idet-10, Common soap etc.)


i) Record the qualitatively observations about the use of different dairy detergent:

1. Solubility
2. Wettability
3. Emulsification
4. Saponification
5. Stability during storage

ii) Record the observations of following utensils for cleaning:

1. Milk cans:
i) Cold/luke warm water required for rinsing
ii) Amount of detergent solution used for cleaning
iii) Time required for scraping
iv) Quantity and temperature of hot water used for cleaning
v) Amount of sanitizers and type of sanitizer used
vi) Time required for complete drying

iii) Glass bottles: As above

Calculations: Calculate the strength of constituents detergents employed to prepare the solution required for washing/sterilizing the utensils on college dairy farm.

Current Category » Practicals on Technology of Milk & Milk Products