DON'T KEEP CUT ONIONS!
Written by Zola Gorgon - author of several cookbooks.
Watch out for those spoiled onions...
I had the wonderful privilege of touring Mullins Food Products, makers of mayonnaise. Mullins is huge, owned by brothers and sisters in the Mullins family. My friend, Jeanne, is the CEO.
Questions about food poisoning came up, and I wanted to share what I learned from a chemist.
The man who gave us our tour is named Ed. He's one of the brothers. Ed is a chemistry expert involved in developing most of the sauce formula..(He's even developed sauce formula for McDonald's.)
Keep in mind that Ed is a food chemistry whiz. During the tour, someone asked if we really needed to worry about mayonnaise. People are always worried that mayonnaise will spoil. Ed's answer will surprise you.
He said that all commercially-made Mayo is completely safe.
"It doesn't even have to be refrigerated. No harm in refrigerating it, but it's not really necessary." He explained that the pH in mayonnaise is set at a point that bacteria could not survive in that environment. He then talked about the quintessential picnic with the bowl of potato salad sitting on the table and how everyone blames the mayonnaise in it when someone gets sick.
Ed says that when food poisoning is reported, the first thing the officials look for is when the victim last ate ONIONS and where those onions came from (in the potato salad?). He says it's not the mayonnaise (as long as it's not homemade Mayo) that spoils in the outdoors. It's probably the onions, and if not the onions, it's the POTATOES. He explained that onions are a huge magnet for bacteria, especially uncooked onions.
You should never plan to keep a portion of a sliced onion. He says it's not even safe if you put it in a zip-lock bag and put it in your refrigerator. It's already contaminated enough just by being cut open and out for a bit that it can be a danger to you. (And doubly watch out for those onions you put on your hotdogs at the baseball park!)
Ed says if you take the leftover onion and cook it like crazy,you'll probably be okay, but if you slice that leftover onion and put it in your sandwich, you're asking for trouble. Both the onions and the moist potato in a potato salad will attract and grow bacteria faster than any commercial mayonnaise will even begin to break down.
So, how's that for news? Take it for what you will. I (the author) am going to be very careful about onions from now on. I see a lot of credibility in this info, coming from a chemist and a company that produces millions of pounds of mayonnaise every year.
(Dogs should never eat onions.. Their stomachs cannot metabolize them.)
http://www.snopes.com/food/tainted/cutonions.asp - Says Undetermined
Check out what "Ed" says in regards to this. I think it is worth taking note of... I am sticking to what I said before... I will not eat or use onions that have been cut up and sat out, even after they have been refrigerated.