Jan 192014
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5373670168_e88553c29bThis is one of my “why hasn’t someone made that yet?” inventions.  It came to me one day when I opened the refrigerator, reached for the one-percent milk, looked at the expiration date, and noticed it was the same day’s date.  

So like any reasonably intelligent person who wants to be sure, I smelled the milk and – yuck…but just for a second. Then it smelled normal!  Hmmm…..

No discoloration, but I couldn’t take the chance.  Plus, I am one of those people who you may call ‘low level-phobic’, as I am inclined to throw away milk or any perishable item on its last quantity-legs, far faster than others.  Does anyone really like to drink the last of the soda?

So what happens when we smell the milk – and it’s a toss-up.  What if you have a cold and can’t do the smell?  Now you really could be out of luck.  

Not to mention, that this printed date on milk has always been a thorn in my mind – errr….side.  Does it mean it’s the “still good” date even after you’ve opened the milk?  Or does it begin from the day it was packaged, even if it stays unopened?  Oh, my mind just swims and swims.  

Here’s a fact.  In the U.S., more than 76 million cases of food-borne illness occur each year.  According to the Food and Drug Administration, such cases have resulted in more than 32,000 hospitalizations and 5,000 deaths.  But in the other corner are those who hate to waste.  Because, studies as far back as 1995 point out that retailers lost nearly 17.4 billion pounds of milk per year because consumers assumed it was spoiled.  

Enter the smart guys.  In 2012, scientists from Tufts University created a sticker made of gold and silk fibers that would stick to a food item and determine its edibleness.  But have you seen it commercially?  Additionally, there is currently a product called The Milk Maid, a quart size milk jug in a glass container that plugs into a ‘smart base’ in your fridge.  I think General Electric is testing it now with consumers.

The smart base of the Milkmaid is able to sense if your milk is spoiled or how soon it will spoil by using pH sensors. Milk, which is made up of nearly 90% water, normally has a pH level of near 6.7.  This makes it slightly acidic.  As the pH level drops, bacteria will make milk sour.  Hence, when it takes a drop, the drinking had better stop!  

So the Milk Maid is neat, to be sure.  But why should people have to buy an aftermarket product when something simpler could suffice?  So here goes…



This invention solves the problem of having to guess whether milk is fresh or not, and at a far cheaper price.  The technology is made by first making all milk caps transparent, instead of colored.  Next, place a small, circular, adhesive bio-sensor with semi-permeable membrane on the inside of the screw-on milk cap.  The inside layer of the sensor, facing the milk inside the carton, would block liquid, but allow gas molecules from the milk to pass through.  

The outside layer, pressing up against the inside of the plastic cap, would have a paper sensor with reagent, much like a dipstick for a urine test at the doctor’s office. This sensor would pick up an increase in carbon dioxide, a known gas offshoot of spoiling milk.  As the CO2 levels begin to increase, it would hit the reagent on the paper tab and change color. 

Perhaps the paper sensor would be colored white when first purchased, and stay white for as long as the milk is fresh. However, once the milk gives off enough carbon dioxide to be ‘freshness-questionable’, the paper would change from white to red.  Anyone picking up the milk could see the color change through the transparent milk cap.  


Guess what?  You can bring the same concept for deli meat baggies at the grocery store.  Sure cheese turns blue, but do you really know when the roast beef becomes stale meat?




  7 Responses to “New Invention – Milk Spoilage Cap”

  1. Steve…just get you a cow so you can get your own fresh milk…Ha!

    I enjoy your thoughts man…keep it up!

  2. I’ve observed that in homes with kids, milk usually does not last long enough for this to be an issue, and a sniff test makes a decent quality check. However, I’ve also seen that with older folks, the milk sits around longer and they don’t always catch that the milk has gone bad. This is a good idea. If you get the FDA or the National Dairy Council behind it, even better!

    • It would seem that way, except I was surprised that in one year 17 Billion Pounds of milk was thrown away! Some of it bad for sure, but I wonder how much waste was in that.
      Hope you are well Chris,


  3. I like the way you think, Steve!

  4. Great idea Steve! For empty nesters it seems that milk actually can spoil before it is consumed.

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