+USDA Mayonnaise Two Months

+USDA Mayonnaise Two Months

 +USDA Mayonnaise Two Months, Best Foods/Hellmann's Mayo doesn't have an expiration date. It has a "Best If Used By" date, which is roughly based on how long it can sit sealed on a grocery store shelf before a critical mass of customers purchasing it will start complaining the mayo went bad too quickly. That critical mass is pretty low, because Best Foods is extremely reputation conscious when it comes to their brands. I'd have no worries opening a jar of Best Foods mayo with a 4/10 date today, or even next April. Once you open that jar, though, the printed date becomes completely meaningless.
A much more important date, when it comes to deciding whether or not opened mayo has gone bad, is when did you open the jar? USDA recommends storing opened mayo for no more than 2 months in the fridge. If you have a good fridge with a steady temperature, you can safely go longer (USDA is also conservative with their estimates), but after two months, I'd be sure check it (look and sniff) before using. +USDA Mayonnaise Two Months, 

Even if it's only a week old, how it's handled can be an issue. If, after opening, somone left it out on the counter overnight, and snuck it back in the fridge without saying anything, that would dramatically shorten the life of that jar. Especially if this happened during the heat of the summer.

I've never encountered a "peanut" smell, even from bad mayonnaise. Perhaps you're smelling rancid oil, and it's evoking peanuts for you. That would be my first guess, and rancid mayonnaise should be thrown away.

Source: can-i-eat-this