If you’re planning to get some spring cleaning done soon, there are four spots you don’t want to forget about.

NBC News reporter Jeff Rossen recently went around his very own home with a bacteria meter and discovered several breeding grounds for dangerous bacteria, including E. coli and salmonella.

Read more: 10 ways you’re ruining your home ‘ and how not to

Dangerous bacteria can make you sick! Here’s what to clean more often

Results from the bacteria meter aren’t rated on a typical scale, but experts say anything over 100 is not good. Here are some of the more shocking findings:

Toothbrush holder: 587 bacteria reading

Your bathroom is full of surfaces that need a regular cleaning: the toilet, shower and sink.

Sitting on the counter nearby those bacteria magnets is your toothbrush holder. In fact, one study from 2011 found the toothbrush holder was the third-germiest item in the entire home.

Luckily, there’s a simple fix. Most toothbrush holders can be cleaned in your dishwasher on the upper rack.

Refrigerator shelf: 904 bacteria reading

This was the most staggering reading from the bacteria meter.

The problem with your refrigerator is that bacteria can spread through cross-contamination. That’s why you must keep meat, poultry, seafood and eggs separate from all other foods in the fridge.

If you see evidence of raw meat juices, you know it’s time to clear everything out of the refrigerator and give it a good cleaning. Vinegar and water will do the trick.

Read more: How to organize your fridge for maximum freshness

Shoes: 290 bacteria reading

Perhaps this isn’t a surprise to Clark.com readers. We’ve reported over the years that you should probably not wear shoes in the house due to the presence of bacteria.

It’s not pleasant to think about, but we walk through things like bird droppings and dog waste on a daily basis, as well as germs on public restroom floors.

In many cases, bacteria from your shoes can be transferred to the flooring in your home.

What’s the solution? In addition to leaving your shoes at the door, cleaning your shoes in the washing machine and disinfecting flooring can go a long way.

Laundry basket

Although the team at NBC News didn’t share a bacteria reading for Rossen’s laundry basket, it’s another thing in the house that we should probably be cleaning more regularly.

After all, laundry baskets carry all of your clean and dirty clothes.

If you use a plastic laundry basket, disinfect it after emptying the dirty clothes. Have a cloth laundry bag? Consider buying a second one to keep dirty and clean clothes separate.

Read more: 42 home cleaning hacks you’ll wish you knew sooner