1. Batch sterilization

2. TOPICS COVERED Design of batch sterilization Del factor
Kinetics of batch sterilization

3. DESIGN OF BATCH STERILIZATION PROCESS
Points to be considered before designing a batch sterilization process-
The profile of increase and decrease in temperature during heating and cooling periods.
Total no. of microorganisms initially present in media.
Themal death characteristics of design organism.

4. It is less successful in avoiding the destruction of nutrients than a continuous one. But still used with minimum loss of nutritive quality.
Highest temp achieved in batch sterilization is 121ᵒ.
In this the contributions to sterilization during heating and cooling peroids is considered.

5. DEL FACTOR
It is the measure of fractional reduction in the number of viable organisms over certain heat and time regime. It is numerically :-
∇=ln (N0 /Nt )
where,
Nₒ= no.of viable organisms before sterilization
Nt = no. of viable organisms after sterilization time t.
Also, ∇ =kt

6. KINETICS OF BATCH STERILIZATION
If the original no of organisms present (Nₒ) is known and (Nt= 10-3) ,the required Del Factor can be calculated.
For e.g: if a specific case in which unsterile broth was shown to contain 1011 viable organism then the Del factor may be calculated as-:
∇= ln (1011 / 10-3 )
= ln 1014
= log 1014
∇ OVERALL =

7. Therefore the overall Dell Factor required is 32. 2
Therefore the overall Dell Factor required is however, the destruction of cells occurs during the heating and cooling of the broth as well as during the period of 121ᵒC, thus the over all Del Factor may re presented as:
∇ OVERALL = ∇ HEATING + ∇ HOLDING + ∇ COOLING

8. ADVANTAGES OF BATCH STERILIZATION OVER CONTINUOUS STERILIZATION
Lower equipment cost
Lower chances of contamination
Easier manual control

9. THANK YOU