Rachel Parsons, a Nutrition Educator at Cornell Cooperative Extension Broome shared her favorite food safety education activity below with us for World Health Day 2015.

Many of my participants don’t understand food may have gone bad even though it doesn’t look or smell any different. Bacterial cells are microscopic, so we can’t even see that they are there. At Cooperative Extension we bring awareness to participants by using meat models made out of common materials that closely resemble ground beef.

We use lentils  to represent bacteria cells, so that participants can “see” what normally they can’t see. The first model represents our starting point; it is safe to assume there are some bacteria present in  with raw meat so the first one starts out with 3 (lentils) “bacteria”. Bacteria cells reproduce quickly  and at room temperatures they double every 20 minutes. The scenario I commonly use is grocery shopping, the moment we took that meat package out of the case it starts warming up to room temperature and our “clock” starts. Our next model shows 6 bacteria at 20 minutes. The next model has 12 bacteria at 40 minutes. And then after an hour, there are 24 bacteria.

Throughout a series of lessons I encourage participants to look at labels, compare pricing, and take their time in the store– but that timer keeps running and the bacteria keep multiplying!. After two hours our 3 starting bacteria have multiplied to 192 cells, and it only takes one to make us sick! Our last model shows that after 3 hours there are more than 1000 bacteria cells present. That package might not look or smell any different but that growth is happening and making that food unsafe to eat.

Participants are encouraged to think of other times  this bacterial growth can happen (dairy foods left out, cut fruits and vegetables, “doggie bag delay”, thawing at room temperature, picnics, etc.). We also encourage participants to think of ways  they can protect their families (purchasing meat and refrigerated products last, bringing a cooler, limit other stops when shopping, safe ways to thaw meat, etc.).

I also share that the two hour limit is reduced to one hour when temperatures are very high, bacterial growth is more rapid at higher temperatures. This use of models  really helps participants understand why the two hour rule is so important in food safety. Our participants share that  they learned the most from and that it led them to change their behavior.