Petri plates, disposal

Culture shaker with test tube racks at 37°C Petri plates (disposable, plastic)... 

The tissue of interest should be removed from the animals using equipment that has been treated to ensure that it is RNase-free. The surface hair of the animals can be soaked in 70% ethanol to minimize the inclusion of hair or dander in the isolated tissues. A sterile disposable Petri plate, placed on top of a bed of crushed ice, is a suitable RNase-free surface for microdissection. Immediately after isolation from the animal, individual samples of tissue can be flash frozen by immersion in liquid nitrogen and stored in cryovials in liquid nitrogen or at -70°C until all samples from an experimental set have been obtained. RNA extraction and preparation of single-stranded cDNA can then be performed simultaneously on all samples. This will minimize differences between RNA populations that result from differences in sample preparation. 

Contaminated labware may include cultures, stocks, petri plates, and other disposable laboratory items... 

Chemical sterilization is not routinely used in microbiology laboratories. In packaging of sterile Petri plates and other plastic disposable supplies which cannot be heat sterilized, the gas ethylene oxide is used. However, given its toxic and explosive properties, ethylene oxide is not widely used in routine laboratory work. 

Once used, pipettes and any nonsterile utensils should be placed in disinfectant and autoclaved at the end of the day. Disposable plasticware, such as pipettes and Petri plates, should never be discarded without first autoclaving. Because this operation will cause the plastic to partially melt, such disposables should be placed in trays before autoclaving. Alternatively, one may purchase disposable autoclavable polypropylene bags for packaging. 

Used Petri plates, plastic containers and pipette tips should be stored in approved autoclave bags ( BIOHAZARD ) for autoclaving along with cultures prior to disposal. Any item capable of causing puncture wounds, such as hypodermic syringes, glass or plastic pipettes, or razor blades, should be placed in covered contained and labeled SHARPS. ... 

Working at the fume hood and away from any flames and hot plates, fill a petri dish about half-full with an organic solvent. Place a Styrofoam cup bottom-down in the solvent and record what happens. Use a glass stirring rod to explore what remains of the cup. Some solvents that might be tested are acetone. 95% ethanol, dichloromethane. and toluene. Properly dispose of all liquids and solids remaining at the completion of this experiment. 

The most common collection methods rely on impaction, the same process as described in Section 5.5 for nonbioaerosols. Slit impactors impact particles directly onto a culture medium. For bacteria and fungal spores, the culture medium, called agar, is a semisolid material containing water and nutrients that foster the growth of the viable particles that are collected. For viruses, cell or tissue culture media are used. Typically, the agar fills a 100-mm or 150-mm disposable petri dish, called a culture plate, that is slowly rotated under the slit to provide a history of bioaerosol concentration. Rotating slit impactors have flow rates of 28-50 L/min and cutoff diameters of about 0.5 pm. 

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