Introduction

Bacteria in my environment

Bacteria are everywhere – we can’t escape them!  There are millions of them in the air we breathe, in the food we consume and on most of the surfaces we touch everyday.  In my first experiment, I will show the presence of bacteria in my environment.

Material

-         seven Petri dishes with agar

-         Q – tips

-         Para film

-         warm place for incubation

-         Environmental samples

o       Ten dollar bill

o       My saliva (on Q-tip)

o       Cat saliva (on Q –tip)

o       My Dad’s finger print

o       My hair

o       Air of the powder room (1 hour)

 

Method

-         labeling of dishes

-         inoculation (except control dish) with samples

-         sealing of dishes with Para film

-         incubation (3-5 days) at 28º

-         observation of colonies and photos

-         storage in fridge     

The sealed dishes are observed after 1, 3, and 4 days of incubation. 

 

Results

TABLE # 1                      
                       
Inoculum 1 day 3 days 4 days Observations            
Dollar Bill 0 25 49 Variety of bacteria, many different colors, different sizes of colonies. Presence of fungi.
Saliva 0 3 4 All colonies are white.          
Cat salvia 0 11 17 Lots of fungi, different types and colors of bacteria.      
Finger print 0 2 10 Colonies badly defined because of cracked agar.      
Hair 0 0 0 No observations            
Air 0 1 1 One beige colony            
Control 0 0 0                
         

 

 

              

Colonies of bacteria grow in every dish except the control and the hair sample.

Conclusion

 

With this experiment we have shown that bacteria are everywhere.  In the inoculated dishes, we observed different colonies of bacteria and for some samples ( ten dollar bill and my cat’s saliva )  fungi grew as well.

This experiment will help us for the second experiment, where we will test the efficiency of detergents on bacteria.  Saliva is the best sample because we obtain many colonies and it is easy to inoculate.  Our incubation temperature (28º) allows us to observe results at 4 days.  These are the conditions we will use for experiment # 2.