How to find out if the fermentation process is contaminated with bacteria? What are the causes of contamination? The way of contamination?
At present, the inspection methods commonly used in production are:
1.microscopic inspection;
2.plate scribing inspection;
3.broth culture inspection.
To determine whether the fermentation is contaminated with bacteria should be based on the results of the aseptic test.
The purpose of the aseptic test
(1) to monitor whether the medium, fermenter and ancillary equipment sterilization is complete
(2) to monitor whether there are stray bacteria invading from outside during the fermentation process
(3) To understand whether there are hidden dangers and dead ends of contamination in the whole production process
Comparison of various inspection methods
The three methods have their advantages and disadvantages, microscopic inspection method is simple, fast, and can be found in a timely manner, but because the microscopic inspection sample issmall,the field of view is also small, so it is not easy to detect early miscellaneous bacteria.
The disadvantage of the plate scribing method is that it takes a long time to culture (generally overnight) to determine the results, and the operation is more cumbersome, but it is less than the microscope can detect miscellaneous bacteria.
Problems in the examination of miscellaneous bacteria
1. Check the results should be the main basis for plate scribing and broth culture results
2. Plate scribing and broth culture should be done in three parallel samples
3. To take regular samples
4. Phenol red broth and plate scribing culture samples should be stored until 12 hours after the can, to determine the sterility before discard
Process and time of inspection
Selecting the production process and time of sample inspection is also a very important issue. Scientific and reasonable choice of inspection process and time, for the removal of contaminated materials, to avoid the next process is contaminated with bacteria, has a direct guidance significance. Sometimes, even if the inspection time is long and the production is not timely, it is indispensable to find out the link that causes the accident of contamination, analyze the cause of contamination and eliminate the loophole of contamination.
Due to the different production of strains of products, the inspection time is not exactly the same: but the general principle is the same, that is, each process or after a certain time should be sampled and inspected.
