Commodity employed in food industry

1. Batch & Continuous sterilization
Techniques

2. Batch sterilization:
 Batch sterilization can be done by injecting the steam into the medium or
direct electrical heating of medium.
 The culture media are subjected to sterilization at 121°C, in the bioreactor for
20-60 minutes.
 For the direct batch sterilization, the steam should be pure, and free from all
chemical additives.

3.  Batch sterilization is the reduction of contaminant organisms.
 The batch sterilization, a system goes through 3 steps:
 Heating, Holding, and Cooling.

4.  The temperature is increased until it reaches the sterilization
temperature where it is held for a set period of time.
 During this phase, most of the unwanted microorganisms are
destroyed.
 Finally, the system is cooled to bring the sterile media back to
the desired temperature.

5. There are two disadvantages of batch sterilization:
1. Damage to culture media:
 Alteration in nutrients, change in pH and discolouration of the
culture media are common.
2. High energy consumption:
 All this process involves wastage of energy, and therefore batch
sterilization is quite costly.

6. Advantages:
 Most widely used technique
 Simple operation
 Low risk of contamination

7. Continuous sterilization:

8.  Continuous sterilization is carried out at 140°C for a very short
period of time ranging from 30 to 120 seconds.
 This is based on the principle that the time required for killing
microorganisms is much shorter at higher temperature.

9.  In Continuous sterilization the culture medium continuously
pumping holding loop.
 Once the media is in a holding loop, steam is injected to the
system via a nozzle.
 The sterile culture medium again pumped into the flash cooler to
bring culture medium to normal temperature.

11. Advantages of continuous sterilization:
3. This process involves less wastage of energy, and
because sterilization complete with in short period.
4. Low risk of contamination.

12. Disadvantages:
 The certain chemical compounds in the medium become
precipitated (e.g., calcium phosphate, calcium oxalate) due to very
high temperature.
 The starch-containing culture media becomes viscous in
continuous sterilization and therefore is not used.

13. Sterilization of Air:
 Industrial fermentations are carried out under continuous
aeration.
 Air can be sterilized by filtration, heat and UV radiation.

14. Air sterilization by heat:
 In the early years, air was passed over electrically heated elements
and sterilized.
 But this is quite expense, hence not in use these days.

15. Air sterilization by filtration:
 Filtration of air is the most commonly used sterilization in
fermentation industries.
 Depth filters:
 Membrane cartridge filters:

16. Depth filters:
 When the air is passed through a glass wool (fibrous) containing
depth filters the particles are trapped and removed.
 The air is pass through this depth filter the microbial cells are
removed by physical screening or entrapment.

17. Membrane cartridge filters:
 Membrane filters made up of cellulose ester or nylon.
 Membrane cartridge filters are smaller in size, simpler for operation
and replacement.
 Membrane cartridge filters has capability to remove Bacteriophages
form air.

18. Thank you .