Elevating Room Sanitation Quality

The HPV process can only be applied in vacant areas and works by distributing the vapor. The vapor results from the controlled flash evaporation of a liquid hydrogen peroxide solution. It takes about two hours to achieve the right conditions; this state is then maintained for approximately 10 minutes. The final phase catalyzes the agent into harmless byproducts, water vapor and oxygen, returning the environment to its original, but now sterile, condition. This residue-free characteristic aided the initial success of the technology, along with the added benefits of ease of verification and material compatibility over both the long and short terms. The breakdown element of water vapor is registered as just a slight, temporary elevation of humidity conditions. The process can be conducted within a range of 10% to 90% relative humidity and a wide temperature range—nothing beyond the typical ambient variation experienced naturally throughout the year. It does not leave behind puddles of water that may require removal, which is significant to plants with dry operations.

Well Established in Other Industries

Hydrogen peroxide vapor use is well established in other industries, many of which made similar transitions from primitive cleaning techniques. Around 95% of the world’s pharmaceutical production companies, likely one of the most scrutinized industries in existence, use HPV for sterilization. The FDA has accepted the technology, which has been scrutinized to a degree far beyond anything required in other industries. For nearly 20 years, the technology has been used with no suitable alternative available. From its conception, HPV has evolved from a focus on small, contained systems and chambers to larger volumes, such as rooms and buildings.

After passing the rigorous demands of the pharmaceutical industry, the technology received a lot of attention from the health care market, where the process is widely used in patient rooms and surgical suites with a view to reducing transmission rates of hospital-acquired infections such as methicillin-resistant Staphylococcus aureus and Clostridium difficile. Manian and colleagues showed that, compared to a single HPV cycle run in a patient room, four manual bleach wipe downs were needed to achieve an equivalent result.

While the target organisms in food production plants are often different from those found in hospitals, obvious parallels can be drawn from the Manian findings. Any similar study in food production environments would likely find even more extreme results, because the latter are often factors of hundreds of times larger in size and complexity than a typical hospital room. Within a hospital room, one can reasonably expect to apply cleaning agents to most surfaces, but can the same be said of areas with 100-foot ceilings and complex production equipment lines? As a result, manufacturers must consider both the distribution and the efficacy of the HPV process.

Not a Line-of-Sight System

HPV technology is not a line-of-sight system. Hydrogen bonding characteristics mean the technology is poor at passive diffusion; however, this limitation is overcome by using high-kinetic energy injection nozzles to ensure thorough distribution. This trait contributes significantly to safety, an aspect discussed further below, because any leak tends to remain resident in its locality.

Within the target environment, every single nook and cranny and piece of equipment will be exposed to HPV, ensuring a high level of biological reduction. This reduction can be demonstrated numerically to show a minimum of a six-log reduction of a Geobacillus stearothermophilus bacterial spore challenge. To perform this test, commercially available stainless steel coupons inoculated with the bacterial spores are placed at predetermined locations. The coupons come prepackaged in small Tyvek pouches that allow the vapor to penetrate accordingly. On completion of the decontamination cycle, the pouches are removed and the coupons incubated in tryptone soy broth growth media. The analysis that follows is a simple pass-fail test: A turbid growth media tube indicates bacterial growth and process failure; conversely, a clear solution indicates the successful deactivation of all the bacterial spores. In the event of a failure, an analysis may be conducted to determine severity.