Question

For each situation, provide a method that allows proper sterilization of the item without destroying the material or product. Remember that an object containing something requires everything to be sterilized.

- The air in a bedroom

- Metal surgical instruments

- A plastic Petri dish with life cultures

- Soiled bedding and clothing from an infected patient

- Apple juice

Answer 1

*Air in bedroom

UV sterilization devices that produce brief pulse of intense UV light that penetrates the cell walls of viruses, bacterium, fungi and mold to fuse the strands of DNA (creating thymine dimers), resulting in cell death. The devices are portable, can be operated by one person with minimal training and can sterilize the air and visible surfaces in a room in minutes. These devices are able to kill bacterial spores at a distance of 2 meters from the lamp in 8 minutes without the use of any chemicals.

*Metal surgical instruments

Steam or autoclave sterilization is the most common method of instrument sterilization. Instruments are placed in a surgical pack and exposed to steam under pressure. A sterilization indicator such as autoclave tape or an indicator strip is used to identify instruments that have been sterilized.

*Plastic Petri dishes with life culture

Plastic Petri dishes with life culture are made harmless and cleaned by placing them in a bacterium-tight heating chamber maintained substantially at atmospheric pressure and contacting them with water at an elevated temperature, preferably 90°-98° C. for a predetermined period of time. After the predetermined period the plates are rinsed with water which is then drained off through an outlet in the bottom of the heating chamber. The agar plates to be treated are loaded into the heating chamber in batches contained in bags wholly or partly consisting of a plastic sheet material which is solid and substantially insoluble in water at room temperature but soluble in water at the elevated temperature.

*Soiled bedding and clothing from an infected patient

All infected linen / linen soiled with body fluids will be soaked in 0.5% bleaching solution for 30 mins then washed with water & detergent to remove bleach before handing over for washing. The process is also called as sluicing.

*Apple juice

Disclosed herein is a method for sterilizing juices that retains the aroma and flavor in the sterilized juice. The process comprises:

(1) heating juice concentrate to a temperature of about 220°F to about 300°F by means of direct contact steam infusion for a period of about 0.5 to about 15 seconds to sterilize the juice

(2) cooling the product to below about 220°F by releasing the pressures resulting in an immediate temperature drop

(3) recondensing substantially all the vapors into the juice

(4) quickly chilling the product to about 30°F to about 60°F.