Sterile liquid paraffin is a high-purity mineral oil processed under aseptic conditions. It appears as a colorless, clear, oily liquid that is odorless and tasteless. Chemically stable and insoluble in water, it is primarily used in medical and laboratory settings as a sterile lubricant for coating the surfaces of endoscopes, urinary catheters, surgical instruments, and other devices. This application reduces friction damage and ensures operational safety. Additionally, in microbial preservation, it is poured onto the surface of slant media to form an oil seal layer. This layer effectively isolates air and prevents moisture evaporation, thereby inhibiting microbial metabolic activity. This extends the viability preservation period of bacterial strains and ensures the biological stability of experimental materials.

Mid stage preservation of bacterial strains: Cover the already grown slant culture with sterile liquid paraffin, isolate it from air, inhibit metabolism, and extend the preservation time.

Suitable for multiple microorganisms: suitable for the preservation of the vast majority of aerobic bacteria, facultative anaerobic bacteria, actinomycetes, yeasts, and molds.

Long term preservation effect: Some strains (such as Yersinia enterocolitica) can be preserved for up to 21-22 years, and edible mushrooms can be preserved for 1-5 years.

Operation points: Paraffin needs to be sterilized under high pressure before injection, with the liquid level about 1cm above the top of the slope. The test tube should be placed upright in a low-temperature (4-6 ℃) dry place.

Recovery culture: During recovery culture, select a small amount of bacterial cells and transfer them to fresh culture medium. As the bacterial cells may be contaminated with paraffin, they usually need to be transferred again to obtain a pure culture with vigorous growth.

Not applicable to strict anaerobic bacteria and strains that can decompose and utilize hydrocarbons, as they may decompose paraffin and affect preservation efficiency.