Final answer:
The FDA approves chemical sterilization, radiation sterilization, and ethylene oxide sterilization for plastics and metals. Ethylene oxide is effective for heat-sensitive items but must be used with caution. Radiation sterilization penetrates packaging materials, making it suitable for sterilizing packaged, heat-sensitive products.
Step-by-step explanation:
The types of sterilization that are approved by the FDA for use on plastics and metals include chemical sterilization, radiation sterilization, and ethylene oxide sterilization. Ethylene oxide is particularly notable for its ability to sterilize items within plastic bags and other heat-sensitive items due to its highly penetrating and alkylating properties, despite its potential hazards as a carcinogen and explosive if not used carefully. Radiation sterilization, which involves the use of X-rays or gamma rays, can penetrate packaging materials and is therefore effective in sterilizing many packaged items, including those made of plastic and metal, without the application of heat. This makes radiation sterilization suitable for heat-sensitive products like medical equipment and certain foods.
While heat sterilization methods, like autoclaving, are effective for a variety of applications, they are not always practical for heat-sensitive materials like plastics and some metals. Therefore, for these materials, ethylene oxide and radiation sterilization are often preferred. However, it should be noted that appropriate aeration and safety measures must accompany the use of ethylene oxide to ensure that the sterilized items are safe and free from any residual toxic substances.