Maddy checks out the choc factory
Did you know one in 50 children is allergic to nuts? In mild cases people can get a skin rash or have problems breathing, but in extreme ones people can die.
Just staying away from nuts isn't as easy as you'd think though, as loads of different kinds of foods often get made in the same factory. That means tiny traces of them can end up in things they're not supposed to.
Maddy's been to a chocolate factory where they've gone to extreme measures to stop that happening!
"Apart from roast potatoes, chocolate is probably my favourite food in the entire world! I LOVE it! But I always feel guilty eating it in front of my friend Helen, who's got a nut allergy.
Like loads of you, she can't eat some kinds of chocolate because they contain traces of nuts. So I was really excited about heading to the first factory in Britain to produce all it's yummy brown stuff in a totally nut-free zone!
No nuts allowed!
Before we could go in, Newsround's camera and microphones had to be tested to make sure we weren't carrying any bits of nut in with us. We weren't even allowed to eat nuts the night before just in case we got some on our skin or clothes!
Experts from the factory wiped a cotton wool bud across all our equipment. They then dipped that in a special chemical that can help show up nut particles.
After that I had to put on a hair net and some enormous white overalls. I looked ridiculous! You have to wear clothes like these in lots of factories to stop germs spreading.
I checked out nut-free chocolate lollies, Easter eggs, and enormous bunnies! The entire room smelt delicious, and when I saw the huge chocolate mixing pots I wanted to climb in!
Then I was shown a huge window in the middle of the room and told to take a peek through the glass. By now, I really felt like I was in Charlie and the Chocolate Factory.
Special nut zone
On the other side of the wall were loads of other workers dressed in red hair nets and yellow overalls. Believe it or not these guys were making chocolate that does have nuts in it!
Even though the people who run this factory think it's really important to make nut-free products, they also want to make chocolate that does have nuts in it too. And they've worked out a clever way to do both!
No one is allowed to move between the sections unless they change into the right coloured clothes and wash their hands as they arrive in and leave each place. There are even special pipes that make sure air doesn't pass between them. And guess what? They're colour co-ordinated too!
So, I popped on some new yellow overalls and a red hat and went to take a closer look. There were huge crates of walnuts inside, and I helped decorate some chocolate whips with them.
Keeping the two areas separate is a massive mission, and some people would probably call the people behind the idea a bit nutty! But they say it is all worth it to make sure thousands of kids with nut allergies don't need to worry about getting sick."