College of Agriculture & Natural Resources

Salmonella in Spices: ENST Student Studies How To Stop Harmful Strains from Hitting The Shelves

Marie-Laure Flamer researches ways to speed up bacteria detection.

When you hear the word “salmonella,” raw eggs, cookie dough and contaminated poultry may come to mind. But what about oregano, cilantro, or black pepper?

Marie-Laure Flamer, a senior Environmental Science and Technology major concentrating in environmental health, is searching for a faster way to identify strains of salmonella in spices before they hit the shelves as an intern for the FDA.

Salmonella cells can latch onto spices in many ways. Sometimes contamination results from packaging and preparation methods. Salmonella is found in animal excretions, which can end up in run-off and travel by water to fields where spices are cultivated. Salmonella can also travel through the air and soil before landing on a plant.

Despite this high risk of contamination, spice plants have antimicrobial properties that fight off harmful bacteria. So why is there a concern about salmonella contamination?

Certain substances like cooking oil seem to prevent the antimicrobial properties from inhibiting the bacteria’s growth. This means that salmonella cells in black pepper may survive when the spice is added to food being prepared on a stovetop.

“It makes you think anything could happen, but it could be the rare chance that the perfect environment was provided to protect them,” Flamer said.

Flamer is experimenting with substances called broth environments that will keep the salmonella bacteria alive and active for at least 24 hours. These growing environments can improve the detection methods spice producers use to more quickly identify salmonella in their samples.

Discovering the salmonella would prompt them to conduct a recall and pull their products off the shelves before consumers could be exposed to the bacteria.

‘The mission is to minimize the risk, protect health and prevent these kinds of incidents,” Flamer said.

When beginning an experiment, Flamer first selects a broth environment. She places a spice sample and salmonella bacteria in the substance, observes the growth of the bacteria and performs a DNA extraction to see if the same strain survives in the broth.

Flamer said the number of salmonella cells she can observe and count on an agar plate indicates how many cells survive and grow in the broth environment.

“A lower concentration is a more accurate reflection of reality,” Flamer said, adding that it only takes about 10 salmonella cells to make a child or elderly person sick.

Flamer works at the Joint Institute for Food Safety and Applied Nutrition (JIFSAN) an FDA and UMD collaborative research facility in Beltsville. She started her internship in June and worked 30 hours per week over the summer, although she said she would stay a little later if there was more to do to prepare an experiment.

During the school year she works 12 hours per week and will finish her internship in May.

“It’s given me the ability to network with a lot of professionals in the field, figure out my career interests and get a sense of the public sector working environment,” she said.

There are five to six people on her team but Flamer works with one or two of them on a daily basis. She meets regularly with her mentor, who helps her brainstorm ideas for the next week’s experiment.

“It’s been really beneficial to have a mentor in the scientific community. It’s been pretty important to see the different things women in the scientific field are doing. She’s a good role model for me,” Flamer said.

Conducting this research has made Flamer think twice about what she eats. She will not eat any uncooked food that contains raw eggs, which can be contaminated with salmonella.

“If I used a raw egg, I am not tasting that. There’s no chance,” she said.

Flamer said that her lab classes prepared her for the internship, even though she hadn’t taken a microbiology course until this semester.

“Even if it’s not in a microbiology area, it’s the process of learning and understanding lab safety, how to carry out an experiment and analyze results,” she said.

She added that the chance to conduct experiments on her own has helped her with her studies at UMD.

“Creating my own experiments is a big plus that I’m happy to apply to my courses here,” Flamer said.

Flamer is hoping to see her research published and is looking forward to postgraduate experiences.

“It will put me in a good place when I graduate and facilitate my steps, so I’m incredibly grateful for this opportunity,” she said.

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