You’re a technician in the lab! Sample bacteria in pasteurized and raw milk, then incubate the bacteria and count the colonies.

The Virtual Labs series of interactive science modules helps train high school and college students in basic laboratory techniques.

Scientists in the laboratory take great care to maintain a sterile environment, making sure that contamination doesn’t enter the experiment from workers' hands or other objects. Students will practice using special disposable equipment to perfect their lab skills while testing milk samples of pasteurized and raw milk for harmful bacteria. Students will inoculate petri film with samples and then incubate the bacteria. Finally, they'll count the resulting bacteria colonies and draw conclusions from what they see. In the second half of the interactive, students will investigate the origin of the bacteria by swabbing surfaces at the dairy to see if they are contaminated.

This work was supported by USDA CSREES and USDA National Institute of Food and Agriculture under two Higher Education Challenge Grant projects: 2008-38411-19055 and 2011-38411-30625. © 2008-2016 NMSU Board of Regents. Collaborating universities South Dakota State University and New Mexico State University are equal opportunity/affirmative action employers and educators.