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Need help with Science Fair food

So my boyfriend's 10-year old son has stated that his Science Fair project for this year is various foods that mold or rot and what their rates of decay are...

The problem is that he should have started the project a month ago and now has less than two weeks to create the offending displays.

His idea included McD's French Fries but I (the family foodie) let him know that he is unlikely to witness any decay in those; they just shrink a little and get hard. Breads and cheeses - those things I am more familiar with going bad - take a while to develop.

Any suggestions of which foods might produce the best sort decomposition in a short period of time?


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  1. Banana.
    Cheese (pref. something squishy).

    1. These should go quickly:

      cooked beans (like kidney beans) (these smell really bad pretty quickly)

        1. re: ricepad

          Rice might be a little difficult to quantify. One thing I learned in a Serve Safe class is that by the time you can see or smell mold/spots/decay/etc. on white rice it has already been unsafe to eat for quite a while. The spoilage occurs on rice before it is detectable by smell or sight.

        2. You know what might be fun is to compare decay rates of the same food. Make chocolate chip cookies with butter, Crisco, a combination. Buy chips ahoy or something like that; as well as grocery store cookies.

          Another idea is to compare something like strawberries--one refrigerated, on room temp, one in a sealed container (will last forever), one in a plastic bag w/ moisture--maybe wash it first, etc. refrigerated and not, some in the sun, and so forth.

          1. Does your local grocery store have a "slightly old produce" section? Starting with aged fruits/veggies could jump-start the project...

            Re. the McD's proposal, tell him to check this out... http://news.yahoo.com/blogs/upshot/mc...

            1. MILK! When I had a similar project as a kid, I took a little Vitamin D whole milk and left about an inch in the bottom of a cup uncovered and unrefrigerated. It developed the coolest green and black molds.

              Avocado breaks down quickly and would look really gross after 2 weeks. Most cut fruit would. Raw meat would be really disgusting. make sure he has a corner of the house/garage where the smells and animals won't be an issue!

              1 Reply
              1. re: mojoeater

                When I was 7, I poured myself a glass of milk just before we left for a 10 day family vacation, and didn't finish it. In the rush, the milk was not dumped out or glass rinsed, but just left on the table until we got home. It was the most beautiful rainbow of solidified milk and mold I had ever seen!! I'm old, and I still remember how cool that looked!

              2. These are all great - thanks!!!!

                1. I did this one (sort of) - I compared Kraft Singles to a slice of regular cheddar and Wonder Bread to a slice of homemade. Not too hard to predict the results, but interesting nonetheless.

                  1. Go to your fresh meat section and look for beef/chicken/fish that has an "additional savings" sticker, which means they are on the edge of going bad.

                    1. Breads from the bakery, rather than the bread aisle, will mold up very nicely in two weeks.
                      Also a pot of coffee or tea left sitting on the counter.
                      Is he just required to have a demonstration, or is there to be a hypothesis /test/results project?

                      2 Replies
                      1. re: jmcarthur8

                        JMCarthur, I'm honestly not sure... The guy is ten years old. I'm letting his Dad figure out the presentation/paper part of the project. I'm the foodie and was asked about the foods that would mold faster.

                        Sadly, I think the kid procrastinated and now has to come up with foods that will mold in a week. He screwed up and the lesson is being learned. Fortunately, I had some Moroccan preserved lemons in my 'fridge that had begun to mold so I gave him those, but after that, I'm not sure what he is going to use.

                        1. re: CarrieWas218

                          One of the boys in my son's class back in the day actually started 3 weeks ahead of time with the moldy bread experiment. It never occurred to his mom that standard gooey white bread would not get moldy in that time. He had 4 pristine slices of bread on his display.