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1.1: Safety Procedures for the Microbiology Laboratory

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    Learning Outcomes

    • Explain & practice safe microbiological procedures, protective measures, and emergency procedures.
    • Identify safe laboratory practices when working in a microbiology lab 

    What is Laboratory Safety?

    Safety in a microbiology laboratory is important in the prevention of infection that might be caused by the microorganisms being studied. In addition, many of the reagents, equipment, and procedures used are potentially hazardous. Attention to proper procedures and prudent laboratory practices are required for your safety and protection.

    This laboratory does not require the use of any highly virulent human pathogens. However, some of the organisms used are potentially pathogenic. This means that, although they may not cause disease in a normal healthy human, they might if the body's antimicrobial defense mechanisms are impaired. Impairment can arise in a number of different ways: wounds and cuts on the skin surface or lowered overall resistance to infection due to: another disease, surgery, stress, or immune system disability (including autoimmune diseases or the use of immuno-suppressive drugs). In addition, infection can occur, albeit very rarely, by relatively nonpathogenic organisms in healthy individuals.

    In addition to organisms, there are some chemicals used in this laboratory that are potentially harmful. Finally, many procedures involve equipment, glassware, open flames, heat sterilizers, and sharp objects, which can cause injury if used improperly.

    Although none of the organisms, procedures, or materials used in this laboratory is very dangerous, proper safety techniques and precautions should be understood and become part of your reflexive laboratory technique. The following laboratory rules and regulations should be adhered to at all times, NO EXCEPTIONS.

    In addition, specific laboratory rules must be followed for containment of microbial cultures in the laboratory, for the safety of all. For this laboratory, these practices are listed below.

    General Laboratory Safety Practices and Procedures

    1. If you are taking immune-suppressants, are pregnant, or have a known medical condition that would prevent full participation in the laboratory, please contact the course instructor before the first day of lab.
    2. Read and understand each laboratory exercise before you come to class.
    3. Do not eat, drink, smoke, or chew pens in the laboratory.
    4. You must wear close-toed shoes while in the laboratory and long pants.
    5. No hats of any kind will be allowed in lab, unless allowed by University policy and cleared with the instructor.
    6. Long hair should be pulled back to keep it away from bacterial cultures, bacticinerator or open flames.
    7. Follow precautionary statements given in each exercise. 
    8. Personal electronic devices will be turned off and stored while in this laboratory. *The unauthorized use of any electronic device (phone, tablet, computer) in lab will result in a loss of course points.
    9. Know where specific safety equipment is located in the laboratory, such as the fire extinguisher, safety shower, and the eyewash station.
    10. Recognize the international symbol for biohazards, and know where and how to dispose of all waste materials, particularly biohazard waste. Note that all biohazard waste must be sterilized by autoclave before it can be included in the waste stream.500px-International_Biohazard_Warning_Symbol.svg_.png
    11. Keep everything other than the cultures and tools you need OFF the lab bench. Only necessary work material should be at or on the laboratory bench. Coats, backpacks, and other personal belongings will not be allowed on the laboratory bench top. Store them in a place designated by your instructor. This is to prevent cluttering of the workspace and to avoid exposing them to permanent stains, caustic chemicals, and microorganisms used in the exercises.
    12. Leave all laboratory facilities and equipment in good order at the end of each class. Before leaving the laboratory, check to make sure the bacticinerator heat sterilizer is turned off.
    13. Never, under any circumstances, remove equipment, media, or microbial cultures from the laboratory.
    14. No pets are allowed in the laboratory.                                                                                                                                                                                                                                                                                                                                                             Figure 1: Biohazard Symbol

    Microbiology Specific Laboratory Safety Practices

    During the course of the semester in the laboratory you will be taught the methods used in the proper handling of microorganisms. Although you will not be working with any that are human pathogens, exercise caution in handling all material coming in contact with live microbial cultures. All cultures should be handled with respect and proper aseptic technique as if they were potential pathogens. This is called "universal precaution". Specific instructions that should be followed:

    1. Remember that all bacteria are potential pathogens that may cause harm under unexpected or unusual circumstances. If you as a student have a compromised immune system or a recent extended illness, you should share those personal circumstances with your lab instructor.
    2. Wear gloves when working with cultures, and when your work is completed, dispose of the gloves in the biohazard garbage. Lab coats, safety glasses or goggles are also required.  These will be stored in the laboratory each week in a ziplock bag.
    3. Disinfect your work area both BEFORE and AFTER working with bacterial cultures.
    4. Cultures of live microorganisms and any material coming in contact with live cultures must be properly sterilized after use in the laboratory. Your instructor will inform you of specific procedures. Follow the general rules outlined below.

    a.  Glassware such as test tubes, bottles, and flasks may be reused and washed after
    sterilization. These are normally placed on a cart at the front of the laboratory
    after you have finished an experiment or exercise. BE SURE TO REMOVE
    LABELS before placing any glassware on the cart. Your instructor will sterilize
    and then wash these items.

    b.  Some materials, such as plastic petri dishes, plastic pipettes, microscope slides,
    and swabs, are considered disposable. These are used once and if they become
    contaminated by contact with live microorganisms are sterilized and discarded.
    All of these disposable contaminated materials should be placed in the designated
    waste container containing a BIOHAZARD autoclave bag.

    1. Never place contaminated pipette tips (or pipettes), inoculating loop, or any other contaminated material on the bench top. Sterilize loops before and after each use. Place contaminated pipette tips in the orange biohazard buckets on your bench. Place all other contaminated materials in their designated waste containers. Do not place or put anything containing live microorganisms in the sink.
    2.  Aerosols should be avoided by the use of proper technique for sterilizing the inoculating loops and by performing any mixing of cultures and reagents in such a way as to avoid splashing.
    3. Cultures or reagents should always be transferred with an automatic pipettor that will be provided. In no case should one employ mouth pipetting.
    4. Always keep cultures capped and in proper storage racks when not being used during an exercise.
    5. In the event of an accidental spill involving a bacterial culture, completely saturate the spill area with disinfectant, then cover with paper towels and allow the spill to sit for 10 minutes. Then carefully remove the saturated paper towels, dispose of them in the biohazard waste, and clean the area again with disinfectant. Notify your instructor about the spill.   If the chemical is marked "danger" or "caustic" you should notify the instructor who will handle this type of spill.
    6. Immediately report all accidents such as spills, cuts, burns, or other injuries to the instructor
    7. Make sure that lab benches are completely cleared (everything either thrown away or returned to storage area) before you leave the lab.
    8. Clothing worn in the microbiology laboratory should be washed before being subsequently worn in a facility such as a hospital, clinic or nursing home, or in an area of public food preparation.
    9.  In the event of a fire alarm, follow the directions of your instructor, and meet at the place designated by your instructor.


    Watch these Videos on basic laboratory procedures:

    *We will review specific safety procedures for our lab during our first in-person lab session

    Watch Video 1: start video at 9:55 - end video at 10:26, covers different types of bench surfaces and cleaning methods



    Watch Video 2: How to put on and take off gloves


    NOTE: The following recommended practices and procedures for working safely on microbiology projects in a teaching laboratory environment are based on “Guidelines for Biosafety in Teaching Laboratories,” from the American Society for Microbiology (ASM). The full documents may be viewed at this URL:



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