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Lessons about apples for Amherst science club 

  • An apple is surrounded by agar plates, used to grow bacteria, as part of testing done by students in the after-school science club at Amherst Regional Middle School. SCOTT MERZBACH

  • Vivian Delcore, 12, demonstrates how bacteria from a cotton swab is applied to an agar plate. Scott Merzbach—Scott Merzbach

  • Vivian Delcore, 12, shows Nora Klotz, 12, how bacteria is removed from an apple using a cotton swab. Scott Merzbach—Scott Merzbach

  • Vivian Delcore, 12, shows Nora Klotz, 12, how bacteria is removed from an apple using a cotton swab. Scott Merzbach

  • Vivian Delcore, 12, shows Nora Klotz, 12, how bacteria is removed from an apple using a cotton swab. Scott Merzbach—Scott Merzbach

  • Nora Klotz, 12, shows Grace Garman, 13, how bacteria from a cotton swab is applied to an agar plate Scott Merzbach—Scott Merzbach

  • Nora Klotz, 12, shows Grace Garman, 13, how bacteria from a cotton swab is applied to an agar plate Scott Merzbach—Scott Merzbach

  • Nora Klotz, 12, shows Grace Garman, 13, how bacteria from a cotton swab is applied to an agar plate Scott Merzbach—Scott Merzbach



Staff Writer
Sunday, June 26, 2016

AMHERST – Fresh fruit is an essential part of the lunch program at the Amherst Regional Middle School, but providing students crisp apples mostly free from potentially harmful bacteria is a time-consuming process for the cafeteria workers.

Each day, these employees take the apples, which arrive refrigerated, wash each fruit in a pan with holes that allows the water to flow through, and then place each apple in a plastic bag, before setting them out for lunch.

But preliminary scientific findings by seventh graders in the after-school science club show that the cafeteria could use a simpler process to get the apples ready that might reduce the level of bacteria even further.

“We think just washing and refrigerating is the best way,” said Vivian Delcore, 12, adding that inserting each apple into a plastic bag closed with a twist tie is not necessary.

“You definitely want to wash it and refrigerate it, but the bags do not help,” said 12-year-old Nora Klotz.

Klotz and Delcore are two of the four seventh graders who spent more than four months performing the science and collecting the data. The club meets for 50 minutes after school every Thursday with their advisers, middle school science teacher Jennifer Welborn and Dhandapani Venkataraman, a professor of chemistry at UMass.

The idea to study apples came from cafeteria worker Diane Tower, said Grace Garman, 13, explaining that Tower was concerned the elaborate preparation may not be reducing bacteria.

“She wanted us to test different methods for handling apples to find the most effective and sanitary method for handling them,” said Amanda Demling, 12.

Conducting the tests

Before the students could embark on the project, they had to learn how to go about testing for bacteria and how to get accurate results.

The seventh-graders began working with UMass microbiology professor Yasu Morita and Anastasia Naritsin, an undergraduate research associate, as well as other Science, Technology, Engineering or Math “ambassadors” from UMass. They showed the high school students how to use cotton swabs to lift bacteria off the apples and then place this bacteria onto agar plates, which are Petri dishes on which the bacteria can grow, and the importance of wearing plastic gloves to prevent contamination.

They first saw evidence that this is an effective way to monitor bacteria by doing control tests and placing the agar plates in an incubator. One control test had the students dab a cotton swab fresh out of a container onto the agar plate, and another cotton swab that was dabbed behind the ear of Klotz and then put onto the agar plate. While one agar plate showed little bacteria, the other became filled with colonies of bacteria.

As the students began their work, they hypothesized that they would find a way that produces less bacteria.

Receiving a number of apples, the students used the current cafeteria method, another that is the current method but with the apples kept at room temperature instead, a third in which the apples were just washed and refrigerated and a final method with no washing or refrigerating.

Each method they did at least three times to ensure there was consistency in the results, monitoring more than two dozen agar plates regularly and writing down observations and changes in a journal.

“We wanted to to find which apple has the least bacteria,” Klotz said. “Less bacteria is healthier.”

“It is safe to assume, under the circumstances, these are not good bacteria,” Demling said.

What they discovered is that washing and refrigeration does even better than the current process.  

Venkataraman said he speculates that the cafeteria’s usual method may increase humidity, which could promote growth of bacteria.

Next steps

The students hope a change can be made after presenting their project to the School Committee and Whitsons Culinary Group, of Islandia, New York, which supplies food for the schools and provides guidance on its safe handling. 

“We want to get this information to the company,” Garman said.

Demling said the club has already alerted Tower about the findings.

Welborn said she supports pushing for adjustments.  “I think it’s worth having them try to change policy,” Welborn said.

“They are trying to effect policy change not with passion, but with data,” Venkataraman said, though he acknowledged more work may need to be done when school resumes in the fall.

Venkataraman said the students spent more than a month coming up with ideas to work on, which also included using rainwater to water the garden at the high school, and building a soundproof booth for mobile recording.

“The key thing is the came up with a good experience for all of us and to get students excited about science,” Venkataraman said.

Garman said she believes the results show that cafeteria workers can serve apples with less demands on their time.

“If we can change the company’s mind, it will help the lunch ladies,” Delcore said. “They have a lot of work to do.”

Scott Merzbach can be reached at smerzbach@gazettenet.com.