Final answer:
Water baths and water bath shakers should contain a bacteriostatic agent to inhibit microbial growth. Bacteriostatic agents differ from bactericidal agents by inhibiting, rather than killing, bacteria. Maintaining the correct water activity and using sanitation protocols helps ensure cultures remain uncontaminated.
Step-by-step explanation:
Water baths and water bath shakers should contain a bacteriostatic agent. This is to limit microbial growth in water. Microbial growth can be influenced by various factors, including nutrient availability, temperature, and water activity (aw). Microorganisms, especially bacteria, require high aw to grow, typically between 0.97 to 0.99. To control microbial growth in laboratory water baths, researchers may add agents that are bacteriostatic, which inhibit the growth of bacteria without necessarily killing them. This contrasts with bactericidal agents, which would outright kill bacteria. Bacteriostatic agents can include mild disinfectants, chemicals that decrease water activity, or compounds that inhibit bacterial enzymes.
Following strict aseptic techniques and sanitation protocols is essential for maintaining cultures in the lab and preventing contamination. While sterilization refers to the complete eradication of microorganisms, it is usually not practical nor necessary for water baths where the objective is to suppress microbial growth enough to prevent contamination rather than to ensure the water is completely sterile.