Sterilizing & Reusing Bags

Anova Precision® Cooker
1

Reusing vacuum sealer and Ziploc bags is a bit of a gray area for some people. Most companies, like FoodSaver, mention you can rinse and reuse their bags as long as they’ve stored fruits, vegetables, bread or dry goods. However, they recommend disposing (recycling) of their bags if they’ve had raw meats, fish, eggs or un-pasteurized cheese in them to avoid contamination. [1]

This is a simple black and white recommendation for bag use, but this doesn’t necessarily mean you need to throw your contaminated bags out after each use. As long as you know how to properly sterilize your bags they can be used many more times, regardless of what food they’ve had in them. Some users have reported getting up to 18 uses from their bags. [8]

First let’s look at what Ziploc and vacuum bags are made of. These products are known as a “film” in the recycling industry, which is a clear thin plastic made of either low-density polyethylene (LDPE) or high-density polyethylene (HDPE). Vacuum sealer bags also contain a thin outer layer of nylon for extra strength. [1][2] Luckily for us, LDPE and HDPE have non-wetting surfaces that resist attack and are easy to clean. Because of this it’s not recommend to clean the bags using abrasive cleaners or scouring pads. [3]

Before looking at sterilization options, let’s reinforce the fact that we want to completely sterilize the bags to rid them of all bioburden and not just sanitize them. [3][4] Tap water, soap and your dishwasher will only sanitize your bags. [5] Sanitizing will work fine if, as mentioned above, your bags have only contained fruits, vegetables, bread or dry goods. Below are various methods for sterilizing your bags along with contact times, product cost, dilution longevity, and if rinsing is required.

Boiling Water

  • Contact Time: 5-10 minutes [6][7]
  • Post Rinse: N/A
  • Product Cost: ¢0.04 @ 1 lt / 34 oz
  • Dilution Longevity: N/A
  • Comments: Boiling or steam microwaving most LDPE and HDPE is not recommend! Their continued use temperature is 65°C / 149°F, softening point is 90°C / 195°F and melting point for LDPE is 110°C / 230°F. [13][14][15]

Chlorine Bleach @ 1:10 dilution (64oz / 5 gallons)

  • Contact Time: 2 minutes [8]
  • Post Rinse: Recommended with cold water
  • Product Cost: $1.25 @ 1 lt / 34 oz
  • Dilution Longevity: 24 hours [9] or longer the higher the concentration.
  • Comment: Alkaline cleaning agents such as bleach may burn your hands without proper protection and can also react to polycarbonate (PC) containers. While this doesn’t directly affect vacuum bags it may affect your sous vide container if exposed to it. [3]

Star-San @ 1:640 dilution (1oz for 5 gallons)

  • Contact Time: 1 minute
  • Post Rinse: Not required
  • Product Cost: $26 @ 1lt / 34 oz
  • Dilution Longevity: Up to 6 months using distilled water or as long as PH is below 3.5 [10][11]
  • Comments: Overtime Star-San can react with nylon and weaken your bags if used on their exterior. [10]

Iodophor @ 1:1280 dilution (0.5oz for 5 gallons)

  • Contact Time: 1 minute
  • Post Rinse: Not required
  • Product Cost: $19 @ 1lt / 34 oz
  • Dilution longevity: 24 hours
  • Comments: Iodophor can leave an iodine odor behind and possibly stain your bags yellow. [12]

While there are other sterilizing solutions out there such as Diversol and UV light I will not be covering them at this point in time. If anyone else has any other recommendations for sterilizing your bags please share, or if you find my information is wrong or misleading please let me know so I can update it as well as provide new references.

References:

  1. Bags & Rolls General Questions FAQ at FoodSaver.com.
  2. How to Recycle Ziploc Bags – RecycleNation
  3. Sterilization Brushes | Brushes Used for Cleaning Plastics
  4. sanitation - What is the difference between Clean, Sanitized and Sterilized? - Homebrewing Stack Exchange
  5. Do Dishwashers Sterilize? | Home Guides | SF Gate
  6. How Long to Boil Water for Purification? | USA Today
  7. How Long Should Something Be Boiled to Sterilize It?
  8. Sous vide: can you reuse the bags if you wash them? - Factual Questions - Straight Dope Message Board
  9. https://www.scripps.edu/newsandviews/e_20060213/bleach.html
  10. Sanitation: How long does Star-San stay good for (mixed up)? | Homebrew Talk - Beer, Wine, Mead, & Cider Brewing Discussion Forum
  11. StarSan pH | BeerSmith Home Brewing Forum
  12. http://www.franklinbrew.org/wp/?page_id=384
  13. Plastic safety - #2 by Roman
  14. Polyethylene | Chemical Composition and Properties
  15. What Are the Dangers of Boiling Food in Plastic Bags? | Our Everyday Life
3 Likes
2

Nice work.

3

Thanks so much for sharing. Reusing bags is really important to cut down on waste, and to not have to always be buying so many bags. Thanks for all the work you put into this! I have just pinned it as the tip and trick of the week, congrats!

5

Awesome post. I reuse my veggie bags but tend to throw away my meat bags. I think the next step in my sous vide journey is silicon bags. Properly sanitizing them after cooking meat will be super important. Thanks for the advice.

1 Like