Does mayonnaise need to be kept cool on a hot dog cart?

When I was a kid we used to have a lot of block parties in my neighborhood. Everyone would bring a dish and set it on a long table in the middle of the street. If the temperature was above 75 my mom would always cast a wary eye at the bowl of potato salad as if it had the potential to kill everyone within a 100 yard radius.

Does mayo go bad in hot weather? New Hot Dog Profits reader Art has some great info on the subject. He writes…

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Hi, I am new to this hot dog cart life and we plan on opening our cart this spring, should be fun, thanks for all the info that is here Steve, we really appreciate it.

Now, it is my turn for putting some information out there.

I want to address the concern people have about mayo and keeping it cool outside. Most, if not all mayos, have a high PH of around 4.2 – 4.5 and if the mayo is a commercially made it was definitely made with pasteurized eggs which makes it virtually impossible for those pesky little micro-organisms to invade the dressing and make you sick.

Years ago some people made their own mayo and may have used unpasteurized eggs which of course could possibly cause issues, leading to the horror stories of people getting sick from potato salad left in the trunk and other interesting events. My mother worked for the health department for years and I have been Serve-Safe certified for many years (we owned a restaurant a few years ago) and in all the Serve-Safe classes I have taken they have told us that mayo does NOT need to be refrigerated even if it is outside.

With that said, your local health departments may have rules and or regulations that require mayo to be refrigerated for some reason and of course you must follow their policies. With all this said, please check with your local authorities and follow what they recommend or require and you won’t go wrong.

Art

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Thanks Art for taking the time to share some well thought out information!

I think the most important point here is to only serve commercially made mayonnaise. The pasteurization is critical as you pointed out.

Yes, mayo is very acidic (right up there with ketchup) and acidic environments severely inhibit the production of bacteria. The funny thing is that acids are more reactive, and therefore kill bacteria more efficiently at higher temperatures.

However this does not mean you should leave your mayo out in the sun. There is more going on here than just acid vs. bacteria.

The bulk of mayonnaise is comprised of oils. Oils (lipids to you food chemists out there)  become rancid very quickly at higher temperatures. While they may not make a person physically ill, rancid lipids taste bad, smell bad, and look bad.

For this reason I still keep my mayonnaise in a cooler at all times on my hot dog cart. I suggest you all do too.

What do you say slingers? I realize that not all health departments allow mayo on a mobile food unit, but if you use it how do you handle your mayo on your hot dog cart?

-Steve