Lab Report on Beef

Stephanie Lamphere December 15, 2013

Nutritional Micro Biology Lab Report #5

Hypothesis: As a class we conducted an experiment to see which meat has the bacteria of E-Coli. We hypothesized that meat that was left out overnight would have the E-Coli present. We used two types of ground beef; we had meat that had been refrigerated, and meat that was left out to sit at room temperature all night.

Materials:

* Ground Beef at refrigerated temperature

* Blender

* Pipette

* Hockey sticks

* Petry Dish with red agar (2)

* Pre-measured sterile water

Results: We collected our evidence on the second day after the two petri dishes had been in incubation. One plate had the ground meat straight up; the other was diluted with the sterile water. When we looked at the bacteria formations we were looking for a dark green almost black color colony, which meant that E-coli was present in the beef. But when we looked at it there were no black spots to be found. We then compared it to the room temperature beef as well, and to our surprise we found the same thing; no black colonies, just more bacteria found in the room temperature beef.

Discussion: We think that because there was no E-coli present in either beef samples because in order to have it present the cow would have had to consume it when it was alive somehow, whether through food or it was present in water. Or if the cow is being butchered, even the butcher could contaminate the meat by having it on their hands. This shows that sanitation was in effect during the meat cutting process.

Conclusion: We concluded that neither meat products contained the bacteria E-Coli. So our hypothesis was not supported by this experiment. This shows sanitation is properly being used.

Refrigerated: Room Temperature:

(Normal) (Normal)

(Diluted) (Diluted)