Shopping for Shopping for Bugs!Bugs!

Presented byPresented by

The 7The 7thth Grade of Grade of

St. George SchoolSt. George School

Introduction Introduction Purpose- to find out how many Purpose- to find out how many colonies of bacteria grow on colonies of bacteria grow on shopping carts. shopping carts.

We picked this experiment because we We picked this experiment because we thought it would be the best way to thought it would be the best way to help people out. help people out.

Our hypothesis is that shopping Our hypothesis is that shopping carts are very dirty because a lot carts are very dirty because a lot of people touch them. Based on of people touch them. Based on reports, shopping carts are not reports, shopping carts are not cleaned and sterilized enough.cleaned and sterilized enough.

MaterialsMaterials

The picture The picture represents represents everything that everything that we used to we used to perform our perform our experiment. We experiment. We also used gloves also used gloves during the during the experiment. experiment.

Methods Methods

Swab carts at different Swab carts at different supermarkets.supermarkets.

Allow time to grow in media.Allow time to grow in media. Plate the samples.Plate the samples. Write down data.Write down data.

ResultsBacteria Growth

0

10

20

30

40

50

60

70

80

A B C

Stores

# o

f co

lon

ies

50 uL

150 uL

DiscussionDiscussion

Our hypothesis was that by plating Our hypothesis was that by plating the sample we could find which the sample we could find which supermarket had the dirtiest supermarket had the dirtiest shopping carts.shopping carts.

The dirtiest supermarket had the The dirtiest supermarket had the most colonies on its plate. most colonies on its plate.

We found that supermarket C was the We found that supermarket C was the dirtiest. (Due to low prices)dirtiest. (Due to low prices)

Strengths and WeaknessesStrengths and Weaknesses WeaknessesWeaknesses

• Only one cart was tested per store. Only one cart was tested per store. • We didn’t know how long the carts were inside or We didn’t know how long the carts were inside or outside. outside.

• We swabbed the carts that were inside. We swabbed the carts that were inside.

Strengths Strengths • We took our time to make sure that we performed We took our time to make sure that we performed the procedure correctly. the procedure correctly.

• We made sure that all of our tools were We made sure that all of our tools were sterilized.sterilized.

• We made sure that all the plates were treated We made sure that all the plates were treated equally. equally.

• The negative control didn’t grow any bacteria.The negative control didn’t grow any bacteria.

Conclusion Conclusion

Our conclusion is that Our conclusion is that supermarket C is the dirtiest supermarket C is the dirtiest out of all three.out of all three.

Supermarket B is the cleanest Supermarket B is the cleanest out of all three.out of all three.

Supermarket A is neither the Supermarket A is neither the cleanest nor dirtiest.cleanest nor dirtiest.

The EndThe End

A special thanks to A special thanks to

Mrs.Catuncan Mrs.Catuncan

Mr. LuuMr. Luu

and and

TEAM SCIENCE. TEAM SCIENCE.