What determines the shelf life of a sterilized item?

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Saturday, October 20, 2018
Medical products must be absolutely sterile and require the highest standards of packaging to ensure they remain uncontaminated even during extended storage. The process of sterilization is just as important as the materials and methods used to ensure absolute safety.

Manufacturers stamp the packaging with an expiry date. In most cases, international standards adopted by manufacturers ensure a shelf life of about five years. However, if stored under ideal conditions and if covered by an extra layer of sterile wrap, the product may have an enhanced shelf life. Conversely, if there are high levels of humidity and if the outer packaging material has cracks or develops defects while in storage, the stored product may have a shortened shelf life.

Shelf life of merdical products depends on a variety of factors. One is the process of manufacture and the manufacturing environment. Manufacturers with protocols adhering to EN ISO 13485, EN 868, EN ISO 11607 and CE standards can be expected to deliver products with an enhanced shelf life. The process in use, such as an absolutely sterile environment, class 8 clean room standards and rigorous quality checks at all stages ensure consistency and reliability. Trusted manufacturers not only have their own methods of quality checks but also get samples tested by independent third parties for higher levels of confidence. The process may vary according to material used and end purpose. Some of the common methods of sterilization in use are dry heat, unsaturated chemical vapor and steam autoclaving, each with its specific advantages. Additionally packaging may carry color indicators to ensure if the contents are sterile or if they have been contaminated. Chemical indicators may be used in conjunction with biological indicators to check for sterilization. The biological indicators may be chosen to be process-specific to assure higher reliability.

Raw materials used in the medical packaging also influence shelf life. Sourcing the best quality materials from top manufacturers and then sample checking before inducting into the process is one way to ensure medical products retain sterility for a longer duration. In such cases it is important to select UV and oxidation stabilized materials with high vapour barrier capabilities and ability to withstand rough handling in transit.

People are just as important to the shelf life of a product because it is they after all who handle the process and implement standards. Manufacturers with highly qualified, trained and professional staff can be expected to take the utmost precautions at each stage to guarantee extended shelf life of medical products packaging. Such packaging may be used in hospitals to temporarily store items while in transit from sterilization section to operation theatres or wards and, in such cases, sealing method of the packaging may determine protection level.

End users such as nurses, attendants and doctors may lack the time to carry out specific tests for each item to determine valdiity of their sterility. In such cases, it is the reliability of a manufacturer, his processes and his product that assures shelf life after sterilization of products. To sum it up, time is not as much an important factor as the events influencing the package.