Question

1. In this experiment we are testing the effect of different chemical concentrations on microbial growth. Let’s say instead we used a 1.0% solution of Bleach against a low, medium, and high amount of microbes.  How would you expect the growth numbers to look in this experiment?
2. In restaurants, most food contact surfaces are smooth and lack cavities/pores in their surface. What is the advantage of that for microbial control?
3. If soaps are not powerful at killing microbes, why are they used for microbial control?
4. What is the difference between an antiseptic and a disinfectant?
5. This lab has mentioned several types of chemical disinfectants/antiseptics, including detergents/surfactants, alcohols, chlorine/bleach, hydrogen peroxide and iodine. Using your lecture slides or the internet, locate and describe a differenttype of chemical disinfectant or antiseptic and explain the conditions under which it is used.

Answer 1

1% bleach is a low concentration of bleach. at such low concentration high amount of microbes cannot be killed. it'll just remove low and medium concentration of microbes only.

2. due to cavities and pores the microbes get accumulated in them and increases the chance of infection but on smooth surface the microbes are not able to make colonies and hence are microbe free to an extent.

3. Soaps are made up of SDS or SLS due creates the pores in cell wall of bacteria. because of those pores water get accumulated in the cell and they get plasmolysed and ultimately die.

4. Antiseptic are used for living surface like human skin, tissue etc. they are less harsh as disinfectants. eg. Dettol. Whereas, disinfectants are strong chemicals used to kill microbes. they contain benzyl alcohol which might cause inflammation or skin irritation on long exposure.

5. chemical disinfectants : at high concentration, ethyl alcohol, isopropyl alcohol, chlorine components, formaldehyde, hydrogen peroxide etc can be used for floors

antiseptics: Ethyl alcohol, isopropyl alcohol, iodine solutions, some chlorine compounds at low chlorine can be used on living tissue. hence, antiseptic.