1920 Explanation of Why Foods Spoil

Line drawing of molds
Source: School and Home Cooking (1920) by Carlotta C. Greer

It’s always frustrating when food goes bad.ย  A hundred years ago cooks also worried about food spoiling . Here’s an explanation of why foods spoil in a hundred-year-old home economics textbook:

Why Foods Spoil

Most foods spoil or change readily – fruits decay, milk sours, butter becomes rancid, and meat putrefies. Knowledge concerning the spoiling of foods makes it possible for the housekeeper to preserve foods from one season to another; it gives her the assurance that her preserved fruit will “keep.”

Line drawing of yeast
Source: School and Home Cooking (1920) by Carlotta C. Greer

The decay of foods is due largely to the existence of minute vegetable organisms or microorganisms. These microorganisms are molds, yeasts, and bacteria. The molds (see Figure 88) are visible to the naked eye, the yeasts (see Figure 86) and bacteria (see Figure (89) are microscopic in size. These plants exist everywhere, and in everything (except those things in which the organisms have been destroyed and prevented from reentering), – in the air, in and on foods, and all over our bodies. Like all plants, these organisms require warmth, moisture, and food for their most rapid growth. Oxygen is necessary for the growth of some of these plants.

Line drawing of bacteria
Source: School and Home Cooking (1920) by Carlotta C. Greer

Many foods constitute nourishment for these organisms. It is because these plants exist in food and live upon them that changes in foods result. The mold on bread and fruit, the odor from decaying meat and eggs, the liquefaction of decayed eggs, and the gas from fermenting canned fruit are caused by microorganisms existing and growing in these foods.

School and Home Cooking (1920) by Carlotta C. Greer

48 thoughts on “1920 Explanation of Why Foods Spoil

    1. I love how the author used very vivid verbs – fruits decay, milk sours, butter becomes rancid, and meat putrefies. Just the word “putrefy” makes me worry.

  1. I remember one of our first science experiments in grade school: putting fingerprints onto small dishes of jello, then putting the dishes into dark, warm places to wait for the mold to grow. My dish went into my closet. It was fascinating.

    1. I can remember doing a similar experiment in high school biology. It was amazing how quickly the bacteria from our hands grew in the petri dish. I remember that a take-away was that it was important to wash our hands.

    1. You’re welcome. It’s important understand why foods spoil, and to know how to prepare foods safely; but I try not to worry much about it.

  2. I really enjoyed this explanation from 1920, Sheryl. It was only around that time that refrigerators were being produced, following the success of the icebox. Very interesting.

        1. How true – sometimes I think that is a skill that has been largely lost across the generations. For example, “use by” dates often are used to determine whether food is okay to eat, rather than using one’s senses to determine whether it is still good.

    1. So do I. I’ve always assumed that since cheese is made using mold, that as long as I get rid of visible mold, the rest of the chunk would be okay.

  3. Ah! A good explanation of the spoilage of food! My family will blame me for not checking the refrigerator often enough. I shall point a finger and say, “You didn’t eat the leftovers!”

    Fast forward 100 years. Depend on your FoodSafe containers to show you when organisms are reaching dangerous levels and post a time when the contents will self-destruct.

    1. I love your “fast forward,” though at the rate change is currently occurring, I think that we’ll have “FoodSafe” containers within a few years. ๐Ÿ™‚

  4. Oh I get to see some interesting molds come from my frig at times. ๐Ÿ˜„ at least mold is more creative and plant like than yeast or bacteria.

  5. Yep. Pretty much what they would teach today. A few different terms, though. Much less food spoilage now with all the preservatives in food today.

  6. Itโ€™s still the same today isnโ€™t it. My sonโ€™s really vigilant about Use By dates but I prefer to use my senses to determine if something is off.

    1. I also tend to consider “use by” dates as suggestions, and use my judgement to determine whether a food is okay. From time to time, I get pieces of lettuce in a salad at a restaurant that has spoiled. I assume that the salad mix had not yet reached its expiration data, and that the restaurant employees therefore determined that it was okay to use without really looking at it.

  7. I just cleaned out a refrigerator in my dad’s basement that probably hasn’t been cleaned for 35 years. So gross. Encased in the glacier that had extended from the little freezer compartment to the adjacent shelf (40’s or 50″s refrigerator) were some mason jars that were canned in the 20’s and 30’s. The rubber rings were disintegrating and the food inside was black. I dry heaved as I opened the jars and dumped the contents in the field. It reminded me of a Stephen King short story, black slimy unidentifiable food. Yuk. And no, I didn’t smell it.

    Interestingly, when we cleaned out the fruit cellar after Gram died in the 80’s, (probably when my dad moved the jars into the fridge) we emptied out a jar of blackberries that she had canned in 1927 and even though the fruit was colorless, no spoilage appeared and it smelled like blackberries.

    1. Whew, this sounds awful. You were very brave to even open the jars to dump them. I may have just thrown the unopened jars in the trash. It’s fascinating how the blackberries still smelled like blackberries 40 or 50 years after they were canned.

  8. I think it was in “Letโ€™s Eat Right to Keep Fit” by Adelle Davis I remember her saying we should only eat food that will spoil but to eat it before it spoils. If microorganisms won’t grow on it then it isn’t nutritious for us. That always stuck with me and gave me pause whenever I was cleaning the inside of the car and found an old fast food french fry under a seat, with nothing growing on it at all…

    1. I’m going to have to look for โ€œLetโ€™s Eat Right to Keep Fit.โ€ I think that I’d enjoy rereading it. Her saying about only eating foods that will spoil, but before they spoil make a lot of sense. Similarly to you, it gave me pause when I went on vacation for several weeks, and returned home to find a partially used loaf of bread sitting on the counter looking just as fresh as it had when I’d left.

  9. All these years later we are still waging the battle. Now with a lot of focus on preventing food waste the information very timely. Here’s to letting nothing ‘putrefy’!

    1. I had similar thoughts when I saw the section in the hundred-year-old home economics textbook about why foods spoil. I found it really interesting how the author chose to simplify things when explaining food spoilage. In some ways I’m surprised how much they knew about microbiology a hundred years ago.

  10. 100-year-old recipes, what a fantastic idea for a blog, Sheryl! We donโ€™t have an oven in our van to produce these eggs, but it will be fun to check out some other old recipes here and see what we can come up with. Your next post about the mushroom croquettes has my mouth watering!

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