Sanitization Methods,Factors and Applications

The aim of sanitization or disinfection in dairy plant is to reduce the number of living microorganisms to a level which is considered safe for dairy processing operation.Usually sanitization does not kill bacterial spores.

 

i. Methods

An effective disinfection/sanitization method requires thorough pre-cleaning. The following sanitization methods are generally used:

Heating by Live steam or hot water: The surface is heated by hot water or steam to inactivate the microorganisms. High temperature will denature protein residues and take them on the surface of equipment so, it is important to remove all debris by initial cleaning. Steam is found highly effective due to high penetration power to reach difficult surfaces. It also takes less time to heat the surface and easy to carry to various places like corners, end places (without use of pump). The high temperature helps in fast drying of equipment surface and achieving extra mileage for reducing water activity. This type of sanitization process requires proper time – temperature combination for better results. The steam is directly exposed to the cleaned surface, whereas hot water is filtered before spraying or circulated over the surface. 

By applying chemical solutions: This method is used where heat sanitizing is not practicable particularly to heat sensitive surfaces/processes. It has been also observed that continual use of a particular sanitizer may lead to the development of resistivity in microorganisms and therefore, it should be changed after some time. Following types of chemicals are used depending upon their suitability.

•  Chlorine & chlorine based products: These are generally used in the form of liquid hypochlorite.
•  Idophors
•  Quaternary Ammonium Compound
•  Amphoteric Surfactants

Application of radiation like Ultra Violet rays: This type of application is getting attention day by day for disinfection of packing machine and materials, air required in the processing for ice-creams manufacture and drying products like peda, kalakand, milk cake etc.

 

ii. Sanitization Effectiveness Factors

Following factors need to be considered while using a sanitizer:

•  The concentration of the chemical sanitizer.
•  The temperature.
•  The contact time required to reduce bacteria to a safe level. The time of surface exposure to disinfectant solution – general wet exposure time of no less than 10 minutes.
•  Condition of surface as sanitizers work best on soil free surfaces.
•  Extent of pre-cleaning. Pre-cleaning removes soil which harbours and protects microbes. Once this protection is removed, microbes are more venerable to chemical sanitizers which can kill or inactivate microbes.

 iii. Sanitizer Application

Application of sanitizers depends upon the method of sanitization and characteristics of sanitizers are discussed below:

•  Flooding: Surfaces requiring sanitization are flooded with sanitizer solutions through circulating solution or dipping the container/machine parts in to the sanitizer solution of desired concentration for desired contact time.
•  Fogging: Fogging of suitable chemicals is done over the place requiring sanitization to inactivate the microorganisms.
•  Spraying: Sanitizer solutions of desired concentration are sprayed over the surface by means of sprayer jets.
•  Effectively exposing the surfaces to the live steam through suitably designed nozzles for killing the microorganisms.
•  Use of radiation for inactivation of microbes. The use of radiation waves placed suitably creates sanitization effect in the close vicinity.