Broth fills sterilization

Extensive process simulation (broth fill) results for BFS effectively demonstrate that high levels of sterility confidence can be obtained with a properly configured and validated machine. However, in order to maintain high levels of sterility assurance, it is important that levels of microbial contamination are controlled within the filling environment. 

There is no appropriate defined sterility confidence level which can be translated directly into acceptance criteria for broth fill contamination for BFS processes. The most commonly recognized acceptance criterion is a sterility assurance level (SAL) of 10 although modem aseptic filling techniques such as BFS can achieve a higher SAL. This should be reflected by broth fill results and acceptance criteria for this advanced technology. 

During the course of a broth fill, operator activity is as necessary as with routine manufacture. However, additional aetivities can be carried out to eover all permissible activities in order to provide evidenee that product sterility is not affected. Such interventions should be plaimed and documented for each batch. 

It is clearly impractical to produce a very high number of broth filled units on a routine basis, but if unpreserved products are manufactured, it is good practice to fill broth directly following product batches with no further machine flushing or sterilization. 

The use of nutrient media that support microbial growth in trials to simulate aseptic operations (sterile media fills, "broth fills ) is a valuable part of overall validation of an aseptic process. Such trials should have the following characteristics ... 

To prepare a seeding culture, fill a 25 pL universal with approximately 10 pL of sterile Mueller-Hinton broth and seed these with 1-2 colonies from the blood agar plate. This is then incubated at 37°C overnight with vigorous shaking at approximately 200 rpm. 

Continuous processes have an even better productivity, especially for slow fermentations. Their disadvantages are their sensitivity to contamination by unwanted microorganisms, and to accumulation of side products, which can interfere with the fermentation. In the continuous mode, the starting culture and medium are filled into the reactor and more nutrients are added continuously as the cells are growing. Part of the fermentation broth is removed at a suitable rate to keep the volume constant. All media must be sterilized before they enter the reactor, which can lead to problems during routine operation. 

To begin the sterile culture portion of ergot farming, a series of 2000 ml conical flasks are filled about one inch deep with nutrient broth made by diluting malt extract with 5 volumes of water. Malt extract is found at stores and outlets catering to the home brewer. It comes in cans, and is a very thick liquid. Avoid the crystalline version of malt extract. The tops of the conical flasks are loosely plugged with cotton, and then sterilized in a pressure cooker at 15 lbs. pressure for a little over Vi hour. 

A flask containing sufficient sterile assay broth to fill all tubes in the test series is... 

A fiask containing sufficient sterile assay broth to fill all the tubes in the test series is inoculated with 20 ml. of a 16-hour broth culture of K. pneumoniae per liter of broth. A Brewer automatic pipetting machine may be used to dispense 7.0 ml. of the inoculated medium to each tube the tubes are covered with inverted stainless steel trays and incubated at 37 °C. for 3.5 hours in a water bath. 

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