Sterilise in place

Pipework systems, valves and vent filters should be properly designed to facilitate cleaning and sterilisation. The use of "dean in place" and "sterilise in place" systems should be encouraged. Valves on fermentation vessels should be completely steam sterilisable. Air vent filters should be hydrophobic and validated for their scheduled life span. 

Modern equipment will also contain computer-based control and monitoring systems by means of which a desired drying cycle programme can be preset. Finally, for pharmaceutical applications, it is essential to prevent cross-contamination between consecutive batches. A clean-in-place (CIP) system and a sterilise-in-place system are therefore provided by means of which the chamber can be cleaned between successive production cycles. 

It is common to sterilise the media and Petri dishes separately. When the medium is cooled to about 55 °C, in front of a flame or in a laminar flow chamber, lift the lid of the dish enough to pour about 25 ml of the medium to the desired depth and lower the lid in place. It is best to gently move the Petri dish in way that spreads a thin layer of agar uniformly without any ah bubbles. Distribution of media in the Petri dishes should be done in front of a flame. Most plastic Petri dishes are made of polystyrene and are not autoclaveable. Plastic Petri dishes are easily deformed during sterilisation at high temperature. Some plastic dishes can be autoclaved, but they ate more expensive. Please follow the instructions given by the manufacturer or obtain information from catalogues. 

Dry heat sterilisation is used for equipment that can withstand high temperature and dry heat but cannot withstand wet or steam autoclave. This method is often used for glassware as it dries and sterilises in one operation. The pipets must be wrapped in dustproof aluminum foil or placed in metal pipette cans. The can lids are removed during heating and replaced after sterilisation, that is before any dust can get in the can. Disposable items are not recommended for dry heat sterilisation. This method may only be good for permanent reusable glass pipettes. 

Resuspend the cells in prewarmed growth medium and filter through muslin or cheesecloth (filter funnels with muslin held in place with autoclave tape can be wrapped in aluminium foil or Kraft paper and sterilised by autoclaving). 

Validation studies should generate evidence that equipment (whether sterilised separately or in place) is subjected to a process that effectively renders it sterile, where this is implied in its use. 

Steam-in-Place Steam-in-place allows the entire healthcare product processing system to be steam sterilised as a single entity, eliminating or reducing the need for aseptic connections. Examples include tanks, filling lines, transfer lines, filtration systems and water for injection systems. 

The use of glass pipettes should be avoided if possible and no mouth operations should be allowed. If it is necessary to use glass pipettes, then these should have a small piece of cotton wool introduced into the mouth end and then be sterilised in cans in an oven. With practice, it is possible to remove the lid of the can, shake out the pipettes, and remove one without touching the others. The lid can then be replaced keeping the other pipettes sterile. These pipettes may then be used with a pipette filler. It requires considerable experience to keep these glass pipettes sterile and avoid dropping contaminated liquid during manipulations. Once used the pipette should be placed into a container of disinfectant. 

Also if products are sterilised in their primary package a low microbial starting contamination is essential. Therefore products to be sterilised must be filled under class C conditiOTis but the preparatiOTi of the bulk solution may take place under class D conditions. 

Prepare and sterilise by steaming a medium of (1 4)2804, 0.2 to 0.4 g KH2PO4, 3 to 4g CaCl2, 0.25 g MgS04, 0.5 g FeSO, 10 mg sulphur lOg tap water to 1000 ml pH 5 0.3 (some authorities recommend a trace metal mixture in place of the ferrous salt). Add 1 ml or 1 g of material to be tested to 100 ml of medium in a conical flask and incubate in air at 30°C. From four days to two weeks the pH of samples should be measured at intervals. An abrupt drop to 2.5 or lower indicates growth of T. thio-oxidans. Little turbidity appears in the medium under a microscope the sulphur particles are seen to be surrounded by motile stubby Gram-negative rods. 

Sterilfiltration sterility Sterilitat sterilizability Sterilisierbarkeit sterilizable sterilisierbar sterilization (sterilizing) Sterilisation, Sterilisiemng sterilization in place (SIP) SIP-Sterilisation (ohne Zerlegung/ Offnung der Bauteile) sterilize/sanitize sterilisieren, keimfrei machen sterol Sterin, Sterol stick /adhere kleben stick injury (needle)... 

As you might have already gathered, the majority of industrial fermentations are batch processes. In closed batch systems, the growth medium is inoculated with cells and growth and product formation is allowed to proceed until the required amount of conversion has taken place. After harvesting the culture the vessel is cleaned, sterilised and filled with fresh medium prior to inoculation. For some processes, addition of all the feedstock prior to inoculation, as is done in closed batch fermentations, is undesirable and it is preferable to incrementally add the carbon source as the fermentation proceeds. Such a process is known as fed-batch culture and the approach is often used to extend the lifetime of batch cultures and thus product yields fed-batch cultures are considered further in Section 2.7.4. 

The production-scale fermentation unit, with a projected annual capacity of over50,000 tonnes was fully commissioned in 1980. The bioreactor (Figure 4.8) is 60 m high, with a 7 m base diameter and working volume 1,500 m3. There are two downcomers and cooling bundles at the base. Initial sterilisation is with saturated steam at 140°C followed by displacement with heat sterilised water. Air and ammonia are filter sterilised as a mixture, methanol filter sterilised and other nutrients heat sterilised. Methanol is added through many nozzles, placed two per square metre. For start-up, 20 litres of inoculum is used and the system is operated as a batch culture for about 30 h. After this time the system is operated as a chemostat continuous culture, with methanol limitation, at 37°C and pH 6.7. Run lengths are normally 100 days, with contamination the usual cause of failure. 

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