New lab paper: The microbes we eat: abundance and taxonomy of microbes consumed in a day’s worth of meals for three diet types

A new paper out from my lab (with Jenna Lang as the 1st author and in collaboration with Angela Zivcovic from the UC Davis Food For Health Initiative and the Department of Nutrition):  The microbes we eat: abundance and taxonomy of microbes consumed in a day’s worth of meals for three diet types.  The work in the paper focuses on characterizing the abundance and taxonomy of microbes in food from three model diets.

Basically, Angela prepared meals for these three diets

Food was purchased and prepared in a standard American home kitchen by the same individual using typical kitchen cleaning practices including hand washing with non-antibacterial soap between food preparation steps, washing of dishes and cooking instruments with non-antibacterial dish washing detergent, and kitchen clean-up with a combination of anti-bacterial and non-antibacterial cleaning products. Anti-bacterial products had specific anti-bacterial molecules added to them whereas “non-antibacterial” products were simple surfactant-based formulations. The goal was to simulate a typical home kitchen rather than to artificially introduce sterile practices that would be atypical of how the average American prepares their meals at home. All meals were prepared according to specific recipes (from raw ingredient preparation such as washing and chopping, to cooking and mixing).

And then she blended them and we characterzied the microbial communities in the blended samples:

After food preparation, meals were plated on a clean plate, weighed on a digital scale (model 157W; Escali, Minneapolis, MN), and then transferred to a blender (model 5,200; Vita-Mix Corporation, Cleveland, OH) and processed until completely blended (approximately 1–3 min). Prepared, ready to eat foods that were purchased outside the home were simply weighed in their original packaging and then transferred to the blender. 4 mL aliquots of the blended meal composite were extracted from the blender, transported on dry ice and then stored at −80 °C until analysis. The following analyses were completed using these meal composite samples: (1) total aerobic bacterial plate counts, (2) total anaerobic bacterial plate counts, (3) yeast plate counts, (4) fungal plate counts, and (5) 16S rDNA analysis for microbial ecology.

And Jenna Lang coordainted the sequence analysis and then Angela and Jenna (with some help here and there from me) coordianted the analysis of the different microbial data and the writing of the paper.

Figure 5: Biplot of taxa in sample PCoA space.

Lots of interesting things reported in the paper (read it, I insist).  I note - this is a demonstration project in a way - trying to get the community and others to think about the source pools of microbes that come into our system from our food.  It is by no means comprehensive or conclusive (read the caveats section of the paper).  Congrats to Jenna and Angela for all their hard work. Anyway - the paper is Open Access in PeerJ.  Eat it up.

UPDATE: Some press and blog coverage

• Kevin Bonham on SciAM Blogs: The Microbes in Your Kitchen (Or in your Starbucks mocha)
• Maddie Stone on Motherboard: Here’s How Many Microbes You Eat in a Single Day
• “This paper will hopefully convince the powers that be that the next study, actually looking at how different foods or diets with differing microbes affect people, should be funded soon,” Zivkovic told me.
• Nathan Gray:  The microbes we eat: Study investigates bacteria in different diets
• Ross Pomeroy on Real Clear Science: This Is How Many Microbes You'll Eat Today
• Improbable Research: What’s Eating You, and/or Vice Versa: Microbes
• Marissa Fessenden at Smithsonian: You Eat Millions...Even Billions!...of Microbes Every Day