Question about expiration times

[rodentraiser]

Chef John has a recipe for blue cheese dressing and someone asked him how long it would last in the fridge. He said about a week or so. So here's where I'm a little confused.

The recipe uses buttermilk, sour cream, mayonnaise, and blue cheese crumbles. These are the things I guess would go bad. But here's my thought: wouldn't the expiration time on it only be limited by the expiration date of what goes into the dressing? In other words, if the buttermilk and sour cream expired in three weeks and the mayo and blue cheese crumbles expired in a month, why, when you combine ingredients, is the expiration time less?

Using the above examples, I would expect the dressing to last at least three weeks in the fridge before going bad. Longer if the sour cream and buttermilk lasted longer.

I've seen this before on recipes. The use-by time is a couple of days or a week but each of the ingredients, taken by themselves, would last at least a couple weeks.

Am I missing something here?

 

[thymeless]

You'll pick up contamination from each spoon you used to scoop out ingredients and the bowl you used to mix it in and so on. Yeah I'd expect it to last more than a week but not really much beyond 10 days. And it's not that it would be unsafe to eat most likely but it won't be as good as it should be.

A lot of these ingredients like the blue cheese and the buttermilk and the sour cream are actually alive already, active cultures. And now you're introducing them to new food sources. So even in your ideal world I'd expect these flavors to change in storage just from the fact that you're using live ingredients.

 

[rodentraiser]

Makes sense. Thank you!

 

[dragnlaw]

Not only what thymless has said - I also find those dates reflect how long a product will last as long as you are very careful about contaminating the contents in your daily use, over and above mixing them with something else.

 

[jennyema]

First of all expiration dates are for unopened packages. Once opened and exposed to bacteria and oxygen, those dates change.

Making blue cheese dressing (or anything) in your kitchen incorporates bacteria into the dressing. Since it’s not cooked, the bacteria multiply very quickly, limiting the time to consume it safely.

 

[Aunt Bea]

Another thought.

When combining several ingredients you can inadvertently change the PH level and shorten or increase the shelf life of the new mixture.


I try to stick with the three day rule and if I’m lucky I never go over by more than a day or two.

 

[rodentraiser]

Now you guys are scaring me. LOL

I usually go by the sniff test. If it smells bad, I won't eat it. Of course, if it looks bad, I won't sniff it either.

 

[taxlady]

Plus, many recipe writers like to state a conservative estimate of shelf life to "be on the safe side".

Meant to post this yesterday. I found it sitting here, waiting to be posted.

 

[taxlady]

Good point about the pH, Aunt Bea.

 

[Aunt Bea]

Now you guys are scaring me. LOL

I usually go by the sniff test. If it smells bad, I won't eat it. Of course, if it looks bad, I won't sniff it either.

I wouldn’t worry too much, your instincts have served you well or you wouldn’t have made it this far.

 

[dragnlaw]

Aunt Bea, your chart shows wine in the 3 day rule -???? What wine lasts more than 6 hours? maybe even 8 or 10 MAX! Silly chartmakers.

 

[taxlady]

Aunt Bea, your chart shows wine in the 3 day rule -???? What wine lasts more than 6 hours? maybe even 8 or 10 MAX! Silly chartmakers.

Are you looking at the chart that Aunt Bea uploaded a little before 13h (1PM) today? That shows pH of foods, not how long they last.

 

[jennyema]

Now you guys are scaring me. LOL

I usually go by the sniff test. If it smells bad, I won't eat it. Of course, if it looks bad, I won't sniff it either.

Never rely on the sniff test. Most foods go bad and can make you sick before they start to smell.

So if it smells or is slimy, its obviously bad. But just because it smells ok doesn't mean it wont make you sick.

 

[dragnlaw]

A play on mixing the words taxy, that's all, just a play on words.