How to Store Petri Dishes: 10 Best Practices for Lab Sterility and Coating Integrity
In any research environment, from basic cell culture to imaging and assay development, petri dishes are foundational tools. Though they appear simple, how they're stored and handled has a significant impact on sterility, surface quality, and the overall consistency of experimental outcomes. Dust, humidity, scratches, and premature opening can all introduce variables that compromise cultures long before they reach the incubator or microscope.
Whether your lab uses standard polystyrene culture dishes, ECM-coated formats, or advanced glass-bottom dishes, the core principles of proper storage remain consistent: protect the surface, preserve sterility, and maintain the physical integrity of each dish until the moment of use.
At WPI, we offer FluoroDish™ glass-bottom cell culture dishes for applications requiring exceptional optical clarity, including fluorescence microscopy, IVF work, and live-cell imaging. These high-performance dishes follow the same storage fundamentals, with a few additional considerations for their delicate 0.17 mm coverslip-thickness glass bottoms and optional coatings like collagen, poly-D-lysine, poly-L-lysine, fibronectin, or vitronectin.
The guidelines below outline universally applicable best practices for storing petri dishes in any research lab, with notes where coated or glass-bottom formats require extra care.
1. Keep Dishes Sealed in Their Original Packaging Until Use
A dish's sterile packaging is its first and best line of defense.
- Leave each dish sealed until you're ready to use it.
- Avoid opening dishes "in advance" or in bulk.
- Always open packages in a laminar flow hood using aseptic technique.
This prevents accidental contamination, preserves coatings, and protects sensitive surfaces, especially the optical window on glass-bottom dishes.
2. Store Dishes in a Clean, Dry, Temperature-Stable Environment
Most petri dishes perform best when stored at 20–25°C (68–77°F).
- Use a dust-free cabinet or drawer.
- Avoid direct sunlight, incubator tops, or other heat sources.
- Keep dishes away from moisture or high-humidity locations.
When stored correctly, sterile petri dishes, including FluoroDish™, maintain full performance and packaging integrity for extended.
3. Refrigerate ECM-Coated Dishes Only When Necessary
Extracellular matrix–coated dishes (collagen, fibronectin, vitronectin, PDL, or PLL) may require refrigeration depending on your usage timeline.
If cold storage is used:
- Maintain 2–8°C (36–46°F).
- Allow dishes to equilibrate to room temperature before opening.
- Prevent condensation from forming inside packaging.
Condensation can alter the uniformity of sensitive coatings and compromise cell attachment.
4. Organize Dishes by Format, Size, and Coating Type
Clear organization improves workflow and minimizes handling errors.
- Store dishes in labeled bins or drawers grouped by:
- Diameter (e.g., 35 mm, 50 mm)
- Coating type (collagen, PDL, PLL, fibronectin, vitronectin)
- Special formats (e.g., 35 mm with 10 mm microwell)
- Label storage containers with lot numbers and expiration dates (if applicable)
- Follow First In, First Out (FIFO) rotation
This ensures consistent use and prevents accidental mixing of coated versus uncoated dishes.
5. Handle Glass-Bottom Dishes with Special Care
For labs using imaging-grade culture dishes:
- Hold glass-bottom dishes by the side walls only.
- Avoid touching the glass surface with gloves or tools.
- Do not slide dishes across the bench. Lift and place them gently.
- >Avoid stacking unless using racks with separators.
FluoroDish™ dishes feature an optical-grade 0.17 mm coverslip-thickness glass bottom. While highly stable for imaging, this precision surface requires careful handling to avoid scratches or pressure damage. However, the glass bottom of a FluoroDish™ is much less prone to scratches than the plastic cell culture dishes.
6. Protect ECM Coatings from Environmental Stress
Coated dishes are sensitive to drying, temperature fluctuations, and UV exposure.
- Keep coated dishes sealed until use.
- Avoid storing coated dishes near heat sources or bright light.
- Discard any coated dish with compromised packaging or visible dryness.
Damaged coatings lead to inconsistent cell attachment and variable assay performance.
7. For Opened Dishes: Use Promptly and Store Correctly
If a dish is opened but not immediately used:
- Keep the lid securely in place.
- Store lid-down in a sterile secondary container.
- Use within 24 hours.
This applies universally but is especially important for coated and glass-bottom dishes.
8. Inspect Each Dish Before Use
A brief inspection prevents downstream issues.
- Check for cracks, warping, or surface defects.
- For glass-bottom dishes, inspect the optical window for scratches or debris.
- Confirm coating type before seeding cells.
- Verify that the sterile seal was intact before opening.
A quick visual check reduces the risk of losing cultures or compromising imaging experiments.
9. Record Lot Numbers and Coating Types for Traceability
For reproducibility and good laboratory practice:
- Log lot numbers for all dishes used.
- Note coating type and dish size.
- Record the date each package was opened.
This documentation is especially valuable for microscopy studies, multi-user facilities, and publication-driven experiments.
10. Dispose of Used or Damaged Dishes Appropriately
Follow your institution's biosafety procedures:
- Autoclave or chemically disinfect dishes before disposal. *
- Never reuse ECM-coated dishes, because coatings are single-use only.
- Never reuse a glass-bottom dish with a chipped or scratched optical surface.
Proper disposal protects both the integrity of your cultures and your imaging equipment.
*Used polystyrene Petri dishes are not heat-resistant and will melt and warp during autoclaving. This is expected and acceptable for waste sterilization. Once sterilized, the deformed dishes can be discarded as non-infectious laboratory waste in accordance with facility guidelines.
Conclusion
Proper storage of petri dishes, whether uncoated, ECM-coated, or glass-bottom, is a simple yet essential component of maintaining experimental sterility, consistency, and reliability. By protecting surfaces, minimizing contamination risks, and handling sensitive formats with care, you ensure that each dish supports the highest quality of work.
For applications requiring exceptional clarity and uniform surfaces, WPI's FluoroDish™ glass-bottom dishes are engineered specifically for live-cell imaging, and advanced fluorescence microscopy. But regardless of the dish you choose, these storage best practices will help safeguard your experiments from start to finish.
