Does Bacteria Growth in Milk Happen Differently in Microgravity than It

Does on Earth?

NEST+m 5th Grade Student Spaceflight Experiment Design

Mammalian Milk in Microgravity

Does Bacteria Growth in Milk Happen Differently in Microgravity than It

Does on Earth?NEST+m 5th Grade Student Spaceflight Experiment Design Team Principal Investigators: Lennie H Ma & Xander PlösslTeacher Facilitators: Zach Vine & Marvin CadornigaraCoordinator: Brendan Alfieri Collaborators: Maury Ahram, Kiara Bracero, Clarisa Carrillo, Kaylyne Cruz, Laila Cruz, Sebastian Delangle, Joseph Dell'Olio, Remmi Duplessis, Mina Ekstrom, Kunal Gahlawat, Kathryn Galperin, Zubin Gell, Kamaya Gooding, Theo Haegele, Dawson Hall, Hayley He, Elliot Leinweber, Cavan Miller, Georgia Podgainy, Nia Powell, Samantha Rapkiewicz, Sasha Roberts, Julien Saunier, Felix Scaggiante, Isabella Serrano, & Riley Sexton

Mammalian Milk in Microgravity

Experimental Background•Microorganisms play important roles in the quality and safety of dairy products• Bacteria are probably the most important group of microorganisms in dairy• Pasteurization and powdered milk production does not kill all the bacteria• Spoilage in space can cause significant problems• A new or better understanding of how milk and other foods spoil in microgravity might allow people to colonize different places in space

Experimental Proposal•Does Bacteria Growth in Milk Happen Differently in Microgravity than It Does on Earth?oHypothesis

Milk will grow and host bacteria differently in microgravity than it will on Earth

A microgravity milk sample will grow fewer bacteria than the ground truth experiment milk sample

oProposal Compare bacterial growth and content of a milk sample

in microgravity to milk samples in full gravity Use standard methods of bacterial examination in milk to

compare samples Work with powdered milk and distilled water to limit the

types and amount of bacterial growth before activation• Spore forming heat thriving (thermophilic) and heat resistant

(thermoduric) bacteria

Experimental Design•Fluids Mixing Enclosure oType 2 FME

6 ml of distilled water 1.5 ml of powdered milk

•Bacterial ExaminationoStandard Plate Count

Culture dilute solutions of samples on agar

Count colony forming units (CFU) and calculate bacteria concentrations

oReductase Test Use methylene blue to indicate the

absence of oxygen due to bacterial growth

Results•Observations

oFlight Sample Returned to Earth intact but seal broke (blow out plug) between

return and laboratory examination Liquid was visible in container bag FME milk sample was dark brown and appeared burnt

oGround Samples FME seals were intact FME milk sample was milky white

•Bacterial ExaminationoStandard Plate Count

Flight Sample averaged 260 CFU/ml milk Ground Samples were greater than 10,000 CFU/ml milk

oReductase Test Ground Sample took more than 8 hours to change color,

indicating a low rate of oxygen depletion Flight Reductase Test inconclusive because of dark coloration of

sample

•Use methylene blue to indicate the absence of oxygen due to bacterial growth

ResultsoFlight Sample

Returned to Earth intact but seal broke (blow out plug) between return and laboratory examination

Liquid was visible in container bag FME milk sample was milky brown and appeared burnt

Analysis• Flight Sample

oLikely causes of FME failure was gas pressure build up from continued growth of bacteria

oDelays between Flight Sample return and laboratory testing contributed to failure

oOnly limited conclusions possible because of FME failure Low Standard Plate Count may have been the result of die off

•Ground Truth SamplesoExpected, high bacterial growth rates were recordedoResults validated basic experimental procedures

• ComparisonoFlight and Ground Truth Samples could not be directly

compared because of Flight FME failureoThe Flight FME showed likely had much higher bacterial

growth as no similar gas build up and failure occurred in any of the Ground Truth Samples

Conclusions & Recommendations

•ConclusionsoWe could not conclude that the Flight Sample had a higher or lower rate of bacterial growth than the Ground Truth SamplesoWe can conclude that there was a greater gas production in the Flight Sample which may indicate a greater rate of bacterial growth

•RecommendationsoExperimental design should better control variables not being tested. Examples:The period of bacterial growth should be shorter to limit varianceHalting bacterial growth before returning Flight Sample would make the sample handling more similar

Temperature is very important in bacterial growth and survival and needs to be the same between Flight and Ground Truth Samples

oSample examination and testing must be well organized and done quickly for biological experiments

Acknowledgements•The NEST+m Student Spaceflight Experiment Design Team would like to thank:oLocal Partner organizations that made SSEP possible for the community NY Space Grant Consortium (Cornell University) Center for the Advancement of Science in Space Step I Review Board

• Marvin Cadornigara, Taehyung An, Richard Sullivan, Joanne Ristau, Katelin Corbett, Evan Feldman, Carla McGreggor, Danielle Neubauer, Hyungmin Park, Zachary Swenson & Richard Sullivan

oResearch Institutions for Sample Prep and Sample Testing Assistance Hunter College, Department Of Biological Science

• George Wallace, Chief College Laboratory Technician New York University

• Professor Edo Kussell, Mark Rocco, & Wei-Hsizng Lin, Center for Genomics and Systems Biology

• Dr. David Greer. Department of PhysicsoAdvisors

Dr. Graciela Ramirez Toro, Director of CECIA, InterAmerican University Steven C. Murphy, Department of Food Science at Cornell UniversityMILK IN

SPACE

NEST+m Student Spaceflight

Experiment Design Team