Students in BIMS 4491 Food Microbiology are deep into a semester of eye-opening surprises. Besides learning the significance of acronyms like HACCP, AOAC, USDA-APHIS, and the like, there has been a tourist’s journey through the microbes used for making foods and those responsible for spoilage. Students have presented case studies on outbreaks of foodborne illnesses from botulism in canned hotdog chili sauce to shigellosis at an upscale hotel. Around every corner there has been a new dimension of how vast the importance of food safety and how costly it is when problems arise.
The first major project for the class has been the production of foods using microbes. From ginger ale to sauerkraut to chocolate, from sourdough bread to cheeses to wines, the class is assembling an impressive array of microbial products for human consumption. A campus-wide reception and “tasting” is scheduled for Thanksgiving week, where a booklet of recipes (complete with a description of the microbes and processes responsible) will be available for our guests.
Today marks the launch of another project. Our students will be headed to college student kitchens to do safety analysis and sampling. Every student in the class had to obtain their food handler safety certification, so things they learned there about safe kitchens will be combined with things learned in class to analyze safety and the practices of college students in their home kitchens. A kitchen user survey and kitchen layout schematic will help Food Micro identify critical points where cross contamination can occur or where safe practices are not being followed (raw meats stored above leftovers in the fridge?). Contact plates of specialized media and swab sample retrieval kits will be used to test cutting boards, floors, countertops, refrigerator shelves, and a variety of other kitchen surfaces. When combined, the results will provide a snapshot of the status of kitchen safety for the average college student. When the data is analyzed, the class will undertake their final class project – writing a guide to safe kitchens for college students. As with our other BIMS classes, we aim to put a practical and useful product together from our semester’s efforts.
There is nothing quite like exposing your students to the way their field is put into practice. There is nothing quite as personal or practical to a student’s education as being the one using knowledge from a course to inform others on how to improve their personal safety. In this way, BIMS 4491 Food Microbiology is demonstrating the great value of learning and applying what is learned for the benefit of others.
In BIMS 1101 Unicellular Organisms Lab, Dr. Benoit takes students through an amazing tour of the unseen world, one filled with bacteria and protozoa and algae and yeast. The course teaches basic cell biology and the diversity that exists among the smallest forms of life. As a way of demonstrating the metabolic diversity of bacteria, all students create Winogradsky columns by filling Falcon flasks with diatomaceous earth, a variety of chemicals, and some water drawn from pond sludge (see photo). These are the students’ pets, cared for and tended to by the students. Dr. B encourages students to drop by the lab regularly to visit their pets and to enjoy their journey to maturation. At the end of the semester, students are free to take them home where they can continue to mature and change for many years.
The preparation begins white usually, but chemical changes caused by a variety of bacterial turn the many minerals present into a technicolor show. A good balance of chemicals and diversity of bacteria can result in reds and greens and blacks and yellows and purples as one species of bacteria after another transforms the minerals into colorful compounds. It is the microbial equivalent of a garden filled with diverse plants.
As educational as the Winogradsky column is, the fun take on the project by Dr. Benoit demonstrates an important component of science at McMurry – if it isn’t fun, something is wrong!
Drs. Benoit and Wilson have long had a love affair with Bacillus thuringiensis (Bt) spores and their study. Their many papers on the subject have often centered on a germination assay that follows the conversion of dormant and resistant spores back to vegetative growth. The assay is based on watching a change in the optical density (absorbance) of spores using a spectrophotometer. It is fast and easy and dependable. At least it was until about 12 years ago when that assay, for some reason, stopped working.
The first indication something was wrong came in the form of an email from a researcher in New Zealand in the fall of 2001. The graduate student was studying Bt germination and ran into difficulty replicating the results Wilson and Benoit had reported. The email simply asked Dr. Wilson whether there were any special tricks involved in the assay. Since neither Wilson or Benoit was involved in research due to administrative responsibilities at the time and had not experienced similar problems, they had no advice to offer.
Fast forward a few years to the creation of the BIMS program and a new graduation requirement that every student must participate in capstone research, an Honors project, or an internship. The department needed research ideas, and Benoit and Wilson resurrected the germination assay as a means to engage students in studying new aspects of spores physiology. The number of unique projects this system would provide for future students was enormous. But the assay failed to work. Even with new facilities and new resources to support research, several student projects failed to recreate results from earlier papers. Nothing in the literature and no one in the field had an answer.
This summer, Honors student Heather Rawls became the most recent student to attempt the assay. Through the summer she tried differences in media, growth temperature, ways of collecting and processing spores, water quality being used, activation techniques, a variety of germinants, and at least five different spectrophotometers with no predictability or consistency in the results. If anything, fewer and fewer spores were germinating with each attempt.
In August, Heather and Dr. Wilson had a research pow wow and developed an alternate project for her Honors thesis. Time was running out to complete her research before starting the writing, and moving to something with a higher probability for success was needed. But Heather wasn’t ready to give up that easily. At an impromptu meeting a couple of weeks ago, a new thought emerged when it seemed every variable possible already had been tested. Glassware! In their graduate programs and during their prior research using the assay, Benoit and Wilson always collected the spores in glass containers and the germinants and all other chemicals used had been stored in glass containers. In our growing emphasis on research, McMurry had improved the funding of science programs so much that the use of disposable plastics was now the norm. Maybe the plastic centrifuge tubes used to collect spores and store germinants were coated with something inhibiting spore germination? Maybe some chemical was leaching out of the plastic?
Over the last two weeks, Heather switched to glassware for collecting spores and making reagents. Her results were dramatically different. We now are certain plasticware has an inhibitory effect on germination. A decade of frustration was caused by our affluence and the use of disposable labware rather than old-school glass.
With a working assay, Heather will turn back to the project she intended to complete this summer looking at the germination of a variety of genetically-engineered and wildtype strains of Bacilli. Another Honors student just beginning her work will investigate what the mystery chemical from the plastics might be and how it inhibits germination, or the range of spore-forming species affected. One mystery is solved, more are uncovered…
BIMS Honors students prove to us on a daily basis that they are among the best thinkers and hardest workers on campus. This commitment to uncovering the truth is what will drive them to become leaders in biomedical science and healthcare provision in the future.