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Organic Lettuce and Gram-Negative Bacterial Science Fair Projects

Bacteria Counts in Organics - Organic Lettuce and Gram-Negative Bacterial Science Fair Projects
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Organic food is examined for bacteria count...

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Organic Produce Controversy

In 2009 a report was published about organic foods. This report stated that there were no nutritional benefits offered by them. However, there are other health benefits offered by organic food.

image of Surface Microbes Science Fair Kit
Test bacteria on any surface with the Surface Microbes Science Fair Projects Kit: after hand sanitizer, hands, disinfectant.. for example. You can use antibiotics to test the bacteria too.

Anytime you want to test how many bacteria are On Top of a surface like a desk, skin, chicken, computer keyboard, bread dough, a hard piece of chocolate, cheese, inside of an animal's cheek, etc. then use the surface experimenter kit. The kit will let you calculate how many bacteria there are per unit surface area on the object. You can also test for e-coli, however, only the microbe water kit will let you distinguish e. coli from other coliforms and bacteria.

 

Objectives/Goals

The goal of the project was to determine if organic lettuce had higher levels of gram-negative bacteria than conventionally grown bacteria. The hypothesis is if the produce was grown organically, then it will have higher levels of gram negative bacteria.

Methods/Materials

Two heads of conventionally grown lettuce and two heads of organically grown lettuce were bought at the supermarket. They were cultured on 9 MacConkey agar plates, four conventional samples and five organic samples, for four days. After four days, the cultured bacteria were counted. The data was logged in a journal and graphed in Excel. The experiment was repeated using twelve organically and twelve conventionally grown spinach samples which had only been dipped in water and minimally processed and shipped up from Arizona in a cooler.

Results

For the store bought lettuce experiment, the organically grown lettuce samples had an average of 24% more gram negative bacteria than conventionally grown lettuce. For the farm direct spinach experiment, the organically grown spinach had an average of 6% more gram negative bacteria.

Conclusions/Discussion

The hypotheses were shown to be correct. Organically grown bacteria did have more gram negative bacteria than conventionally grown lettuce. One factor that may contribute to organically grown lettuce having more gram negative bacteria is because organic farms use fertilizers with feces. However, the margin between the sample averages in the second experiment (the farm direct) suggests that the difference in bacteria may not be as big as originally thought. 3rd party contributor


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Find the truth about organic produce with organic lettuce experiments.