Steam vs Dry Heat Sterilization: How to Choose the Right Method for Your Application

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People are more health-conscious now than ever. Thanks to the pandemic, sterilization is now a topic of interest for many. Industrial sterilization, however, is also a topic of interest to many businesses. It’s a critical process in the medical, research, laboratory, biotechnology, and pharmaceutical industries. Sterilization is an expanding marketplace thanks to the demand in these industries—a demand that’s expected to grow at a CAGR of 12.2% from 2020 to $23.7 billion by 2027. 

But with so many sterilization methods to choose from, however, it can be hard selecting the right one for an application. Basically, there are only two questions you need to ask when selecting a sterilization method:

  • What method(s) can I use to sterilize my product safely and effectively?
  • What method is the most cost-effective manner to sterilize my product?

Once you’ve answered these questions, choosing the proper sterilization method—and the right industrial process oven—for your application is easier. Hopefully, this post will help clear up the confusion surrounding sterilization methods.

Types of Industrial Sterilization Methods

Industrialization sterilization works well in many industries because of the sensitive nature of production in those markets and the need for safety and controls in the production, testing, and distribution stages of products. Sterilization kills living organisms from specific environments and product surfaces.

Any articles applied directly to a human or an animal should be sterilized, including drugs, food, surgical instruments, and nutraceuticals. Sterilization blocks the transmission of microbes from substances when consumed or administered to living beings. It also protects the substance for a long time without decaying.

Manufacturers use several methods for industrial sterilization. Each method fits a particular sterilization operation, environment, and operating condition. Industrial sterilization methods include:

  • Radiation
  • Solvents
  • Chemical
  • Filtration
  • Thermal or heat 

Thermal or heat sterilization is the most common method in the industry. It applies heat directly to a substance or product to kill the microbes in or on the substance. The heat you apply must be in touch with the substance or product for a minimum of time for sterilization to occur.

Types of Heat Sterilization Methods

Two basic approaches to heat sterilization exist. One approach is moist heat sterilization, where heat is applied to boiling or steaming, such as pasteurization or autoclaving (by steam). Temperature and duration are two critical factors with this sterilization approach. Generally speaking, the longer the exposure to heat, the better.

The second approach is dry heat in the form of flaming, incineration, radiation, or hot air oven, like Despatch’s sterilizing ovens. These ovens are useful in medical device manufacturing and pharmaceutical production. Typical applications include glass vial sterilization, decontamination of pre-sterilized products, syringes, and medical surgical rods and staples.

Both sterilization methods work well in the right situations. Steam sterilization is the method of choice for many applications, but dry heat sterilization has its uses. See below for more details:

  • Steam sterilization often occurs in autoclaves. This method produces a highly intense heat, which leads to hydrolysis and coagulation of proteins, kills microbes, spores, and viruses. Steam sterilization exposes an item to steam at a temperature of 121°C for 15 to 30 minutes. Increasing the temperature shortens sterilization time.

Steam sterilization is simple, rapid, and effective. It’s also safe, low-cost, and efficient. It uses less energy than dry heat, which increases productivity and cuts costs. It’s ideal in devices composed of stable, heat-resistant materials, including rubber, metals, and durable plastic materials.

  • Dry heat Sterilization exposes an item to a temperature of 170°C under normal air pressure for about an hour. This length of time ensures that even the most resistant spores are eradicated. Dry heat, which generates similar results to steam sterilization, is less efficient than steam. But it has a lower initial cost, lower maintenance cost, and lower operation cost than steam sterilization.

Specific applications require dry heat sterilization. It works well, for example, on hydrophobic items, such as fats and oils. It also works well on items that may be damaged by moisture, such as powders, or on items that may corrode. Liquids boil off if exposed to dry heat and are incompatible with dry heat sterilization. Growth media, flammable substances, and dense loads are also incompatible with dry heat sterilization.

Steam Versus Dry Heat Sterilization

Choosing the right sterilization method for your application is critical. But with so many methods to choose from, it can be confusing. Steam and dry heat sterilization are the most common methods of industrial sterilization. Both methods are widely used in the medical, research, laboratory, biotechnology, and pharmaceutical industries

While steam is the sterilization method of choice in many applications, there are some cases where dry heat is more appropriate. Both methods, however, are effective when used in the right situations under the right operating conditions and in the right environments. The key is knowing when to use each method.

If you have questions about choosing an oven for your thermal processing application, you can check out our field guide to buying industrial ovens. Or, you can call our skilled customer service team to assist you. Please call 952-522-4931.

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