Food Safety and Insulated Covers

Do insulated covers keep your food or formula cold enough?

I can’t speak to any covers but my own. And I can only really speak to the conditions I’ve tested them in.

In my covers, I use high quality fleece made for sport use (coats). Not just the stuff you can buy at the chain store. And it may interest you to know that I do testing with most batches of fleece when they come in. I’m not required to by law, so I’ve never sent them away for third party testing (nor do I know where I’d do that) but I do run them through some testing here.

And I encourage customers to verify for themselves that their setup, regardless of what it is, keeps their food at a safe temperature.

Here’s what I did during my most recent round of testing, which was when I moved a few new fleeces into production.

– Sewed up a few testers with the fleece. In this instance, I was unsure about whether one of the rolls I have would be enough on its own – it’s a new item number I’ve not used in the past – so I made one with just that fleece by itself and one with that fleece paired with a thin but heavy fleece I have onhand.

– Filled the feeding pump bag (500ml) with a home blend that was in the fridge (approx 250 mL), and another with water that was probably fridge cold (about 400 mL), though I didn’t check the start temp and probably should have (it wasn’t in the fridge, but the place I store the water jugs is very cold in the winter). I keep the small fridge at 38 deg F.

– Suspended an analog thermometer inside the feeding pump bag so that it hangs roughly in the very middle. I usually do this with a patent pending (j/k) high tech system I’ve devised made entirely of pipe cleaners.

– Hung the whole thing up on the IV pole with an ice pack.

– Came back 4 hours later and 8 hours later to check the temps.

– Did this 3 days in a row.

Results at 8 hours were unsatisfactory for the new fleece by itself (averaging 40.5, though it averaged a wee bit over 39 at 4 hours) but the average of the two layers was 39 in the home blend and 37 in the water. At 8 hours, the ice packs were still approx. better than half frozen. (Refrigerators should be 40 degrees or lower. The FDA says that food can be left at room temp for 2 hours.)

I left them for additional hours on the last day, intending to check hourly, but… didn’t. The temp was around 41 at 12 hours. By that point, the ice packs were less than half frozen. This holds up well with what I’ve seen in the past – the results depend a LOT on the ice pack that’s used. Once that ice pack starts to go soft/liquidy, the temp of the associated food starts to go up.

That said, in the real world, I don’t have a stationary, full bag all day. The bag empties over time so there’s less volume for the slowly depleting ice pack to keep cold. Then I refill it with new, typically cold food that I’ve had in another cooler.

Things I haven’t tested:

– Using two ice packs. A LOT of my customers use two ice packs (one on each side) if they’re going to be out all day or for overnights.

– Using YOUR ice pack.

– Formula. IDK if it’d be different.

– Pouring in room temperature food. I’m not sure how quickly an ice pack can realistically bring a room temperature food down to refrigerator temperature.

– Very hot temps. We get satisfactory results here and we don’t have a/c, but I change out the ice pack throughout the day. If you’re outside on a hot day, be especially mindful of your food temps.

I’m also not sure how to (or whether to) account for the fact that prepackaged blended foods, formula, and home blends can safely be at room temperature for various lengths of time. (consult the manufacturer of your food or the USDA for guidance on this.) In theory, if I’m using Brand X packaged blended food, it can hang with the ice pack until the ice pack can’t keep it cold any more and then it still has x hours at room temp.

And I cannot emphasize enough that these aren’t refrigerators. I don’t know how many people contact me to ask if you need to use an ice pack. YES. Yes, you need to use an ice pack. Maybe two, depending on your situation. You need to use a sizeable ice pack if you want to use the cover for all day or all night. Nothing about these covers actually generates cold. 🙂

Anyway. Thought I’d share. If you own one and you do testing with a thermometer at your house, I’m interested in your findings!!


Author: sarahtar

Hi, I am Sarah, owner of Wallypop ( and Boulevard Designs ( I homeschool, work from home, and, along with my husband, raise 3 kids, one of whom has special and medical needs. Turn ons are people who are polite, honesty, and really good root beer. Turn offs are mean people and people who make my life more difficult.

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

This site uses Akismet to reduce spam. Learn how your comment data is processed.

%d bloggers like this: