Feb 25, 2026
Biofertilizer Samples: A protocol for safe handling, application and disposal
- Md Shakil Uddin1,
- Maria J Torres2,
- Lisa Kelso2,
- Yang Tian2,
- Jehangir H Bhadha1,
- Eric S McLamore2
- 1Soil, Water, and Ecosystem Sciences, University of Florida;
- 2Biological and Agricultural Engineering Department, University of Arkansas
- University of Arkansas Biosensor Engineering Lab
Protocol Citation: Md Shakil Uddin, Maria J Torres, Lisa Kelso, Yang Tian, Jehangir H Bhadha, Eric S McLamore 2026. Biofertilizer Samples: A protocol for safe handling, application and disposal. protocols.io https://dx.doi.org/10.17504/protocols.io.n92ld1nb7l5b/v1
License: This is an open access protocol distributed under the terms of the Creative Commons Attribution License,  which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited
Protocol status: Working
We use this protocol and it's working
Created: February 18, 2026
Last Modified: February 25, 2026
Protocol Integer ID: 243659
Keywords: Biofertilizer, biosafety, handling, disposal, microorganism, bacteria, disposal of liquid biofertilizer formulation, liquid biofertilizer formulation, biofertilizer sample, biofertilizers for research, biofertilizer, basic biosafety practice, basic biosafety practices during handling, soil microorganism, occurring soil microorganism, concentrated liquid preparation, protocol for safe handling, disposal, disposal this document, best practices for the safe receipt, safe handling
Funders Acknowledgements:
National Science Foundation
Grant ID: CBET-2019435
Abstract
This document outlines best practices for the safe receipt, handling, dilution, application, and disposal of liquid biofertilizer formulations used in research. While these materials may contain naturally occurring soil microorganisms, concentrated liquid preparations increase exposure potential and must be handled with care. Adhering to basic biosafety practices during handling, application, and disposal significantly reduces risk. This protocol is designed to be used in labs that use and/or develop biofertilizers for research.
Guidelines
This standard operating procedure (SOP) applies to all personnel handling liquid microbial formulations associated with biofertilizer research, including researchers, students, collaborators, greenhouse staff, extension personnel, and workshop attendees.
Materials
Personal Protective Equipment (PPE)
- Disposable gloves (mandatory)
- Lab coat or protective outerwear
- Eye protection when pouring or diluting liquids
- Closed-toe shoes
- N95 masks required PPE when a biosafety hood is not available
Cleanup materials
-Spray bottle
-Biohazard bags
-Ethanol (70% by volume)
-Bleach (10% by volume)
Storage containers
- High-Density Polyethylene (HDPE) are the most common choice for storage containers.
- Any sealable container may be used, as long as the material is: chemically inert (no leaching, no antimicrobial surfaces), non-reactive with media components, leak-proof with reliable seals, compatible with recommended storage temperatures, able to tolerate slight internal pressure changes, easy to disinfect externally.
Troubleshooting
Safety warnings
**General biosafety**
- Microorganisms commonly found in soil are typically present at low environmental levels. Commercial and research formulations may contain these organisms at much higher concentrations. As with any concentrated biological material, appropriate precautions are required to minimize accidental exposure through skin contact, inhalation of aerosols, or splashes to the eyes or other soft tissues.
**Eye protection**
- Laboratory eye protection is required at all times, as significant hazard to eye exposure exists for all liquid biofertilizer samples.
**Skin protection**
- Wear long pants, lab coat, closed toed shoes and gloves at all times when handling biofertilizers.
**Disposal**
- See protocol for detailed guidance on proper disposal.
Read Before Starting...
This standard operating procedure (SOP) applies to all personnel handling liquid microbial formulations associated with biofertilizer research, including researchers, students, collaborators, greenhouse staff, extension personnel, and workshop attendees.
Safety information
Ensure ample space is available for storage, and containers are managed in a well-ventilated area.
Safety information
Laboratory eye protection is required at all times, as significant hazard to eye exposure exists for all liquid biofertilizer samples.
Safety information
Wear long pants, lab coat, closed toed shoes and gloves at all times when handling biofertilizers. See section 2 for accidental spill procedures
Safety information
Create a disposal plan before handling any material that involves Biosafety. See protocol for detailed guidance on proper disposal.
Precaution: Spill or Exposure Response
Follow the guide below for any accidental spills
Note
Accidental spill on counter:
1. Absorb liquid with paper towels or absorbent material.
2. Disinfect the area using 10% bleach for 10 minute contact time after completion
3. Dispose of cleanup materials in a sealed bag and label with Biohazard sticker
4. If contact occurs on large portion of PPE and/or clothing, remove contaminated clothing to be placed in a bag for washing in hot water with detergent, use a spray bottle to saturate contaminated area with 70% ethanol for a 10 minute contact time, then wash any exposed skin with soap for 30 seconds using a soft bristle brush.
5. Wash hands thoroughly with a germicidal soap.
6. Report spills or exposures to a supervisor.
For additional informaiton, see the protocol by Wilhelm et al
Note
Accidental spill in a biosafety cabinet:
1. Allow the Biosafety Cabinet to run continuously, do not turn off.
2. Cover spill with paper towels.
3. Pour (don’t spray) 10% bleach onto area. Carrefully pour bleach around the periphery of the covered spill moving inward slowly.
4. Wait at least 10 minutes
5. Using clean paper towels, wipe up the spilled material.
6. Using a spray bottle, disinfect the area using 10% bleach for 10 minutes
7. Place all cleanup materials into the appropriate biohazardous waste containers.
For additional information, see the protocol by Humphrey
Note
For skin contact:
1. Wash with soap and water for at least 10 minutes under running water.
2. Clean area near spill (follow directions above)
3. Report spills or exposures to a supervisor.
Note
For eye contact:
1. Rinse with clean water in certified eye wash for at least 15 minutes.
2. Clean area near spill (follow directions above)
3. Report spills or exposures to a supervisor.
Receiving and Storage
Follow the guide below after receiving a liquid biofertilizer sample:
- Inspect containers upon receipt for leaks or damage.
- Label the container with the receipt date and your name.
- If not provided by supplier, all liquid samples should be stored in an autoclavable plastic or glass bottle. Examples of autoclavable plastic include polypropylene and polycarbonate.
Polypropylene is an autoclavable plastic. Use caution, not all plastics are safe in the autoclave
Keep containers sealed when not in use.
Note
For example protocol describing use of autoclave, see by Fahrner.
Use local procedures and protocols for your specific autoclave equipment.
Label container(s) with Biohazard label. Clearly label with contents, date received, and responsible point of contact
Biohazard labels may be purchased as stickers for easy placement
Wrap Petrifilm around the lid 2-3 times as a secondary seal on the lid.
Note
If not specified by supplier, store containers at 4 Celcius. A generic holding time for liquid samples with live culture is one week when stored at 4C. After the expiration date, follow instructions under Disposal section
Use secondary containment when storing liquids in refrigerators or cold rooms.
Example of secondary storage container from Thermo Scientific
Safety information
After handling biofertilizer samples (even sealed containers), remove gloves after use and wash hands thoroughly with a germicidal soap. The US Center for Disease Control (CDC) guidelines recommend at least 20 seconds handwashing with soap using a soft bristle brush.
Dilution of Concentrate
Follow all instructions below for sample handling and dilution.
Safety information
Do not eat, drink, or touch your face in handling areas.
Perform transfers and dilutions in a well-ventilated area; use a biosafety cabinet if available.
Safety information
Wear splash-proof safety goggles or a face shield during all pouring and diluting
If pipetting sample, tips should be exchanged between samples to prevent cross-contamination.
Note
For best practices in pipetting, see the Protocol series by Sjorgen and Goller
When handling liquid solutions, be careful to avoid splashing and actions that may generate aerosols. Keep containers closed when not actively dispensing.
Perform dilutions in a well-ventilated area and exchange pipette tips to avoid cross-contamination.
Place all discarded materials going into a biohazard red bag to be autoclaved or disposed of in an incinerator
Clean work surfaces with 10% bleach for 10 minute contact time after completion.
Safety information
After preparing dilutions, remove gloves after use and wash hands thoroughly with a germicidal soap for at least 20 seconds using a soft bristle brush.
Application Example (Greenhouse)
The example below is for greenhouse studies. Other applications may require specific precautions. The list of examples may be expanded as needed.
Safety information
All personnel involved in application activities, whether in laboratory, greenhouse, or field settings, must follow the procedures outlined below to minimize risk of accidental exposure to themselves, bystanders, and the surrounding environment.
Pre-Application Preparation:
- Review the product label or research formulation data sheet prior to application to confirm concentration, recommended dilution ratio, and any application-specific precautions.
- Confirm that the application area such as greenhouse bench, growth chamber, or field plot is cleared of unnecessary materials, food, drink, and personal items.
- Ensure a spill kit such as paper towels, 10% bleach solution, biohazard bags are readily accessible before beginning application.
- Verify that all containers are properly labeled with contents, concentration, date prepared, and responsible personnel.
- Assess weather conditions before proceeding if working outdoors. Avoid application during high winds or rain to prevent drift, runoff, or unintended environmental dispersal.
Personal Protective Equipment and Safety Precautions:
Safety information
- Wear gloves during application.
- Wear long pants, lab coat, closed toed shoes and gloves at all times when handling biofertilizers.
- Decontaminate tools and surfaces following using a 70% alcohol solution in a spray bottle.
- Follow all safety tips and procedures in steps 1-2
Photo of appropriate PPE for greenhouse studies with biofertilizer
Application Instructions:
- Apply liquid fertilizer slowly and carefully to prevent splashing. Hold dispensing equipment close to the target surface. Do not pour from height to limit splashing
- For small volumes, a pipette is recommended. See step 4 for general tips on pipetting and links to other protocols
- If using a spray bottle or pressurized applicator, use the lowest effective pressure setting and a wide-angle nozzle to reduce fine mist.
- Keep containers closed when not actively dispensing to prevent accidental spills and to reduce aerosol exposure risk.
Safety information
- Do not use application equipment for any other purpose after contact with biofertilizer.
- Treat all such equipment as biologically contaminated.
- Apply product in accordance with the approved research protocol. Post warning signs at field entry points during and after application to alert others of the treated area.
Application of biofertilizer to pot with germinating corn using a pipette
- Work systematically from one end to the other to avoid reaching over recently treated plants and risking contact with applied material when applying to plants in trays or pots.
- Maintain a buffer zone from water bodies, drainage channels, and non-target vegetation as specified in the experimental plan.
Post Application Instructions:
- Decontaminate all tools and application surfaces using a 70% ethanol solution applied via spray bottle.
- Clean all work surfaces such as benchtops, trays, any contacted equipment with 10% bleach solution for a minimum 10-minute contact time after completion of the procedure.
- Place all disposable materials such as gloves, paper towels, pipette tips, absorbent pads in a red biohazard bag. Seal and label the bag with the biohazard symbol and the date.
- Autoclave or treat any reusable application equipment such as spray bottles, syringes, trays with 10% bleach for at least 20 minutes before washing or storage.
- Remove lab coat or protective outerwear carefully, rolling it inward to contain any contamination. If contaminated, place it in a bag for washing in hot water with detergent.
- Remove gloves by inverting them during removal and place them directly into the biohazard bag.
- Wash hands thoroughly with germicidal soap and water for at least 20 seconds.
- Document the application in the laboratory notebook or research log.
General Waste Disposal
- Treat unused material, empty containers, gloves, and absorbent cleanup materials as biological waste.
- Dispose according to local best practices for biological materials.
- Sample containers should be autoclavable if they are to be reused
- Do not pour concentrated material down drains unless explicitly approved.
- Decontaminate reusable equipment before storage.
Acknowledgements
This work was supported by the Science and Technologies for Phosphorus Sustainability Center, a National Science Foundation Science and Technology Center (CBET-2019435). Any opinions, findings, and conclusions or recommendations expressed are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.