Rapid sterilisation

Rapid sterilisation of media is achieved by using microwave ovens. Most plant tissue culture media can be sterilised using a microwave, although it may not be suitable with a medium containing complex additives like oatmeal. 

Retortable plastic packages have not yet lived up to their potential for rapid sterilisation. Improved filling rates will depend on faster methods of achieving seals of guaranteed integrity. Reduction in the scalping of flavour by improved plastics, possibly with crystalline or other coatings will further widen horizons. 

Where sea-water is available, electrolysis provides an efficient method of sewage treatment. The sewage is mixed with sea-water and passed through an electrolytic cell. Hypochlorite is formed and rapidly sterilises the sewage, which then sediments out the latter process is assisted by the gelatinous precipitate of magnesium hydroxide which forms in the alkaline solution. 

The converted mash is pumped to a clean sterilised fermentor and the yeast inoculum is added. The set temperature range for whiskey fermentation of 72 hours is usually 17—21°C. At the beginning, the mash converted composition is approximately 80% sugars, mainly maltose and some (<1%) dextrose (primary conversion). The pH is adjusted to reduce initial bacterial growth. Grain neutral spidts are usually set at 27—29°C to expedite fermentation. Temperatures above 35°C inhibit yeast reproduction and promote rapid bacterial growth. Above 40°C actual yeast kill occurs. 

At 70—140°C, peroxide is vaporised. Peroxide vapor has been reported to rapidly inactivate pathogenic bacteria, yeast, and bacterial spores in very low concentrations (133). Experiments using peroxide vapor for space decontamination of rooms and biologic safety cabinets hold promise (134). The use of peroxide vapor and a plasma generated by radio frequency energy releasing free radicals, ions, excited atoms, and excited molecules in a sterilising chamber has been patented (135). 

The solid-liquid separation of shinies containing particles below 10 pm is difficult by conventional filtration techniques. A conventional approach would be to use a slurry thickener in which the formation of a filter cake is restricted and the product is discharged continuously as concentrated slurry. Such filters use filter cloths as the filtration medium and are limited to concentrating particles above 5 xm in size. Dead end membrane microfiltration, in which the particle-containing fluid is pumped directly through a polymeric membrane, is used for the industrial clarification and sterilisation of liquids. Such process allows the removal of particles down to 0.1 xm or less, but is only suitable for feeds containing very low concentrations of particles as otherwise the membrane becomes too rapidly clogged.2,4,8... 

Glass-coated and plastic beads are available from Cellon (Bioglas beads), ICN (Rapid Cell G and Rapid Cell P) and Nunc (Biosilon) and do not swell in aqueous solutions. They are sterilised by autoclaving at 121° for 15 min in water. 

Thaw the ampoule in a 37°C water bath as rapidly as possible using gentle hand agitation. Immerse the ampoule in 70% alcohol to sterilise outside (remember liquid nitrogen is not sterile). 

Desired properties. Innumerable compounds have local anaesthetic properties, but few are suitable for clinical use. Useful substances must be water-soluble, sterilisable by heat, have a rapid onset of effect, a duration of action appropriate to the operation to be performed, be nontoxic, both locally... 

The ampoules were filled with the CRM solution and left in contact with the solution for at least 24 h. After the conditioning each ampoule was emptied, filled with the solution and immediately heat-sealed. The samples were sterilised by gamma-irradiation with a °Co source, dose 25 kGy. After irradiation the ampoules were stored at ambient temperature in the dark. Some differences were observed in the contents before and after irradiation, particularly in the CRM 408 for hydronium, ammonium and nitrate. It was suspected that nitrate could have been formed from ammonium upon irradiation. Nitrite was also detected immediately after irradiation but was probably rapidly oxidised. 

It is strongly toxic both to eggs and adults it sterilises adult females. It penetrates leaf tissues rapidly and maintains its activity there for a long period. Its acute toxic LDjo for mice is more than 3000 mg/kg. 

Edifenphos was degraded in flooded soil samples more rapidly than in nonflooded soil at 50% water holding capacity. A Pseudomonas strain utilised edifenphos as the sole carbon source. Soil sterilisation retarded degradation of edifenphos (Rajaram and Sethunathan, 1976). 

Ammonium thiocyanate by itself is not used as a herbicide, although at a rate of 80-100 kg/ha it is suitable for total weed killing. At the same rates, it can be used for defoliation and for temporary soil sterilisation. It is rapidly absorbed both by the roots and the leaves of plants and is translocated. 

The sampling procedure used will obviously depend on the type of sample whether it is liquid or solid fresh, chilled or frozen and the type of container e.g. tinned, bottled). Other major problems are the frequency of sampling and the position on a production line from which a sample is taken. For example, when sampling from a food production line is carried out, an important consideration is whether or not the food has been subjected to sterilisation, or any form of pasteurisation after the point from which the sample was taken. This is considered further in the chapter on food microbiology under the concept of Hazard Analysis Critical Control Point (HACCP). Whatever the form of the sample, it should be collected in a sterile container using aseptic techniques, returned to the laboratory under conditions identical to those from which it was taken, and processed as rapidly as possible. 

With sterilised products, only chemical deterioration limits the shelf-life as microorganisms are not involved. With spore-containing products the germination of spores must be inhibited. With pasteurised products, refrigeration must be adequate or spoilage will be rapid it is possible that psychrotrophic pathogens that survive pasteurisation or are added by post-... 

Prisms from AcOH. M.p. 213°. Spar. sol. H,0. CHCI3. Insol. pet. ether. Sol. alkalis, re-pptd. by acids. Explodes on rapid heating on Pt foil. H3 d. by phosphates, and borates. Powerful germicide. Us for sterilisation of drinking water. 

Degradable PE samples were sterilised by UV exposure at 254 nm (2x5 min) and inoculated over 30 minutes with a suspension of different strains (bacterium and fimgus). Assays and controls were incubated for six months at 27 °C and 85 % humidity in an environmental cabinet. Cultivations were carried out in Petri dishes containing glass beads and a mineral salt medium [56]. It was observed that the heated films oxidised more rapidly than the control at the end of the induction period. 

Membranes 5 cm in diameter are a convenient size for use in sterility testing. Assemble the membrane in a suitable holder (various types made on the Seitz filter principle are available) with a glass or metal cover-lid and sterilise either with steam in the autoclave or with ethylene oxide. Connect to a convenient receiver and filter the test sample through the membrane, solid samples having previously been dissolved in sterile water or saline. Filtration is rapid if a vacuum is applied. Wash the membrane through several times with water or saline and then remove it aseptically from its holder, cut it in two with the aid of sterile forceps and scissors and culture one part aerobically and the other anaerobically in the appropriate media. 

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