Why we avoid products labelled “may contain nuts”

Do you avoid products with precautionary labels (“may contain nuts” or equivalent wording)? We do. A fellow nut mum recently asked me why this was, as her doctors had advised that she could safely ignore such warnings. I thought it would be worth explaining my thinking.

Our doctors’ advice

We were given the same advice when my son, D, was first diagnosed with a peanut allergy. Our allergy doctors told us (1) to check the ingredients list on food labels, to make sure there was no mention of peanuts or any other nuts and (2) that we could disregard advisory or precautionary labelling (“May contain nut traces”, “Produced in a facility that also processes nuts” and so on).

I think the logic behind this advice is that:

  • The risk of a food labelled “may contain” containing enough peanut to trigger an allergic reaction is extremely slim.
  • As a side point, there is a concern that if we cut out “may contain” foods too, D could have a restricted diet.

Furthermore, given “may contain” labelling is completely voluntary (and will continue to be so when the new labelling regulations come into force in December 2014), is a product labelled “may contain nuts” any more dangerous than another product where the manufacturer knows there is a cross contamination risk, but chooses not to flag this on the label?

Cross contamination: assessing the risk

In the UK and EU, the ingredients list on prepacked food must be accurate. If even the tiniest amount of peanut (for example) has been intentionally added to the recipe, then “peanut” should be listed in the ingredients.

“May contain” labels are intended to alert consumers to the possibility of accidental cross contamination during the production process. So, for example, if your supposedly nut free breakfast cereal is produced in the same factory as nutty granola, the manufacturer might put “may contain nuts” (or an equivalent warning) on your cereal packet.

A few points worth making about “may contain” labels:

  • They are voluntary. If there is no warning wording, you cannot safely assume there is no cross contamination risk.
  • If the manufacturer chooses to use a “may contain” label, you have no way of knowing whether the risk is genuine or whether the manufacturer is just trying to cover its back.
  • You cannot gauge the level of risk from how the warning is phrased. For example, a product labelled “Not suitable for nut allergy sufferers” is not necessarily more high risk than one labelled “May contain nut traces” (and vice versa).

An opposing view from the Anaphylaxis Campaign, Ireland and the University of Nebraska

In the early months following diagnosis, we followed our doctors’ advice and focused only on the ingredients list. However, as I touched on in my recent post on Oreo, our attitude to “may contains” has evolved. When I started Nutmums.com in January 2013 (and particularly when I joined Twitter), I began reading a lot more about food allergies and allergen labelling law. I realised that many allergic people avoid products with advisory labelling. In fact, it seemed as if we were in the minority for not having sworn off “may contain” products.

I then discovered that the Anaphylaxis Campaign advises people to “heed the warnings every time” and that ignoring the warnings is “risky behaviour”. Two recent studies have further underlined this approach:

  • An Irish study tested 38 food products with peanut or nut “may contain” warnings. Peanut was detected in 5.3% (2 of 38) of the products tested. The study concluded “Although it appears that the majority of food products bearing advisory nut statements are in fact free of peanut contamination, advice to peanut allergy sufferers to avoid said foods should continue”.
  • Similarly a study by the University of Nebraska discovered detectable levels of peanut in 8.6% of foods labelled “may contain peanut” (or similar advisory wording). This study concluded that “Peanut-allergic individuals should be advised to avoid such products regardless of the wording of the advisory statement”.

In the UK, the Food Standards Agency have:

“been working to reduce the unnecessary use of ‘may contain’ labelling and to provide clear advice to the public on why these labelling terms are used and what they mean.”

The FSA hopes to publish the outcome of this work shortly.

Peanuts, murderers and lightning bolts

I read recently in the Metro that “People with a food allergy are more likely to be murdered than to die from their condition”. A comforting statistic? Not really. As to my mind, psychopaths can come after anyone, but my son’s one of those with a target on his back where peanuts are concerned.

Similarly for the adage that you’re more likely to be struck by lightning than die from a food allergy. If you’ve got a peanut allergic child with a prior history of severe anaphylaxis, it kind of feels like your kid is the one with the 50 ft conducting rod pointing at them.

It’s also not just about death (although, it goes without saying, that’s the main overriding worry). I don’t want my son to have ANY kind of allergic reaction, if I can possibly help it. I don’t want him to be on life support again, even if within a week he is back home building Lego and watching CBeebies as if nothing has happened. I don’t even want him to spend one night on the children’s ward for observation after a mild reaction, IF I can help it.

The statistics about murderers and lightning bolts might offer me some perspective on his allergies generally. However, they’re not something that would influence my decision on may contains. Avoiding a food labelled “may contain nuts” is something I can do. It’s an element of this whole food allergy business that I can control. There may only be a slim chance that a food labelled “may contain nuts” actually contains enough peanut to trigger a reaction. It may therefore follow that the chance of a life threatening reaction from a “may contain” product is incredibly small. But it’s not outside the realms of possibility and it’s a risk that’s easy to avoid.

Why we avoid products labelled “may contain nuts”

In summary:

  • If a manufacturer has decided to state that its product “may contain nuts”, I take that statement at face value and avoid the product.
  • Even if the chance of a reaction to a may contain product is extremely unlikely, that chance still exists.
  • We’re only dealing with a nut allergy, so, whilst it may mean more time spent searching for nut free options, I don’t feel D has a restricted diet by avoiding products labelled “may contain nuts”.

So, for now, for us, any product with a “may contain” label doesn’t even make it as far as the shopping trolley. If there is no warning wording, I then have to resort to checking the manufacturer’s website or emailing their customer services team.

For me it comes down to this. Would I forgive myself if I knowingly gave my son a product labelled “may contain nuts” and he had an allergic reaction? No. Would it be any comfort whatsoever, if a doctor then told me what had happened was “incredibly rare”? Precisely.

So, until the law on advisory labelling is improved, we will continue to avoid “may contains”.



  1. We too avoid all products that say the May contain nuts. It would be great if labelling could be trusted but it’s a complete minefield. It would also be helpful that if it says made in a factory which handles nuts. It would be beneficial to know which nuts that factory handles.

    1. I also avoid all foods labelled may contain ect..You just can’t be too careful, ok it may be only a 1% chance it contains enough allergen to cause a reaction or 100% you just never know.Simply wouldn’t risk my son’s health or god forbid life.

    2. Hi Carly – thanks for the comment! Yes, it must be particularly infuriating for those avoiding only certain types to read a blanket “may contain nuts” warning.

  2. Great post! I believe the same applies to milk. I’ve definitely noted reactions in our little one, when we’ve crossed the boundary – more often than not. Although, she’s not anaphylactic, the smallest amount seems to register in her digestive system and I don’t want her to live with constant tummy aches and diarrhea. I do worry about products not containing ‘may contain’ when perhaps they should. Really wish this had been made law.

  3. I disagree. I have previously had positive skin prick tests to 30+ foods and if I decided to avoid may contain labels my diet would become impossible. Despite eating many foods with may contain, I haven’t had anaphylaxis since I was 2 (15 years). Maybe I’m biased because I have tasted ‘forbidden fruit’ but I couldn’t imagine going back to avoiding may contain foods. When my mother was feeding me, she did her best to only feed me the foods that I had not reacted to. I wish now that she had been a bit more risk taking as I still avoid certain fruit and veg that I am likely to be ok with, simply because I have never had it and therefore have no idea whether or not I would have a severe adverse reaction. Ok. rant over. Good luck with managing your children’s allergies, but try not to make it any harder than necessary, as then the decision is passed on to the allergy sufferer who may not be emotionally mature enough to decide to risk their life for the sake of more food in their diet, and therefore stay on the restricted diet they’ve been on since weaning. This isn’t so healthy for someone in their teenage years.

    1. Thanks for your comment. I do appreciate that everyone has their own individual attitude to risk and that not all food allergic families will approach “may contains” in the way we do. For me, particularly given my son’s reaction history, the risk of anaphylaxis just isn’t worth it. As we’re only ruling out nuts, I don’t feel my son’s diet is compromised by avoiding may contains. Thanks for commenting – interesting to hear a perspective from someone with multiple allergies.

      1. Hi Louise

        I’ve been trying to get my head around the new changes and found that previously ok foods now are off limits to my Son (6 years old) He has multiple allergies, milk, eggs, nuts, sesame, pea, chickpea, lentils & all pulses and green beans – it’s an absolute nightmare trying to find foods he can have, he never eats out and if we do go out I prepare all his food and take it with me. “May contain nuts” or “made in a factory that handles nuts milk etc” are the biggets pain in my life – nestle cereals were all fine until the changes and now we have had to wipe all these from his diet because of the nut warnings – again I agree with other comments made about manufacturers just covering themselves but don’t realize how these decisions affect people with these allergies – again why can’t they list what nuts are causing the risk as there are some nuts he can eat. I’m in two minds about whether to take that risk with these warnings as his diet is so limited making it so difficult to have that varied diet kids really need

  4. Great article Louise. I’m with you, I don’t think its worth the risk. Recent medical opinion to me also was its ok to eat these products as the risk is very low. I tried it for a while, agreeing first with my daughter we would only eat ‘may contain’ products if I was with her. It was fine until my daughter had bad stomach pains for hours after eating a bar that said ‘May contain traces of peanuts’ so we are back to avoiding them. But like you we are just avoiding nuts & egg white and I can see how it would be very restrictive if avoiding multiple allergens. Also if you follow the Irish & UK food safety authorities allergy alerts, allergen food recalls are quiet frequent & some of these are due to cross contamination when the allergen is on site so we are back to being cautious. Hopefully with the work they are doing on allergy labelling it will get easier to decide.

    1. Hi Anne, Thank you! That’s a good point about the allergy alerts. Very interesting to hear about your daughter’s experience when trying may contains – and has convinced me even more to steer clear.

  5. We too avoid ‘May contain’ foods (for nuts). However my son also has an allergy to mustard (not anaphylaxis) which we are more relaxed about.

    What is infuriating is the way some supermarkets cover their a*ses with blanket warnings! M&S and Tesco are the absolute worse. As a consequence there’s very little we can buy in either store. I once approached an M&S store manager to ask why their dreaded ‘blue nut label’ was plastered on most of their products…I was met with a computer says no attitude.

    On the flip side, Waitrose and Sainsburys labeling is much more coherent and less hysterical.

    1. Thanks Lara – yes, we made a quick switch to Ocado when my son was first diagnosed – find it relatively easy to find nut free options (although I’m now getting wary of having found a comfort zone and ordering the same food week in week out!).

  6. We also avoid the ‘May contain nuts’ foods as I don’t want to take any chances. My sons allergy to peanuts and tree nuts was picked up through a blood test (he took part in a study in the hospital he was attending for ecezma) so thankfully we’ve never had to deal with anaphylaxis! Hes also allergic to eggs but he can tolerate hidden egg so we are more relaxed about this and his doctor reckons he will grow out of this as he gets older, hes 5 now. My 2 year old daughter is not allergic to anything but its funny watching her look at boxes and tell you shes checking for nuts for her brother!

    1. Hi Laura – best of luck with outgrowing the egg allergy. And that’s great you’ve got a little helper for label checking… think I’ll definitely have to train up D’s little sister to do the same!!

  7. What drives me completely potty (was going to say nuts ha ha) is that my son is only allergic to peanuts, not tree nuts. So a label that says “may contain nuts” to me does not contain peanuts, as peanuts are not nuts!
    However, I have to assume that they do mean peanuts.

    I have noticed a lot of small companies and foreign food (esp from the states) say something much more useful such as “may contain tree nuts” or even “may contain almonds”
    I dont understand why all food labels cant have that kind of information on them.

    1. Hi Candice – Know what you mean! – I’ve assumed the same, because you just can’t guess which manufacturers are meaning “tree nuts” and which are meaning “all nuts”. My son’s only allergic to peanuts, but we avoid all nuts (I appreciate there are different approaches on this one!). Absolutely agree though, the more specific information the better, so people can make an informed choice.

  8. My son was diagnosed with a severe nut allergy around a year ago. At present, we have been advised to avoid all nuts. There were certain products he had always eaten and so I continued to allow him to have them, despite ‘may contain nuts’ being placed on the labelling. My son ended up having a reaction to a cookie he had always eaten no problems. Yet another trip to the children’s ward and I took the decision that anything foods that say ‘may contain nuts’ should be avoided. For us it simply is not worth the risk.

    1. Hi Naomi, Sorry to hear about your son’s reaction, but thanks very much for sharing this – it convinces me even of the need to avoid may contains.

  9. I’m sorry but I don’t think this article makes any sense: why avoid “may contain nuts” if it’s not the law to include it anyway if it’s necessary? To me, the only response to your argument is to cook everything from scratch as “you can never be sure”.

    I’m allergic to nuts and peanuts and carry an EpiPen. I’ve not got a blanket approach of staying away from “may contain nuts” and haven’t had an anaphylactic shock since my first episode. I just use common sense: I avoid food like granolas, chocolate and cookies where it’s obvious there is a possibility for cross contamination. If the item says “may contain traces of peanuts” I tend to stay clear as I’m more allergic to peanuts.

    Okay, there are people with more severe allergies than I have (I can be in a room with peanuts, or a plane with peanuts being served). But, you can’t have a bad experience with higher-risk items (or with your children) and then have a blanket approach, or even fear a bad experience in the first place. In my opinion you’re not giving your child the foundations to feel comfortable when eating as an adult. How are they going to cope at low-risk restaurants when everything “may contains nuts”.

    1. Hi Brian, Thanks for your comment. Like I said above, I appreciate that our approach isn’t the only approach and people have different attitudes to risk. My son may well decide to eat “may contains” when he’s an adult too.

      I think I am giving my son a straightforward foundation to work from: avoid foods where (1) there are nuts in the ingredients or (2) where a manufacturer has deemed it necessary to warn consumers something “may contain” nuts.

      As regards restaurants, we eat out with my son often, each time checking with the restaurant which dishes have nuts in the ingredients and that they understand cross contamination. So, our logic is essentially the same for both eating in and eating out, and I hope this stands him in good stead when he’s independent from us and making his own choices.

      1. You have more control with restaurants with regards to talking to the chef and the staff, but the principle is the same: anything at a restaurant may contain nut traces when nuts are used somewhere.

        With regards to (2) – haven’t you established that a manufacturer doesn’t have to warn consumers by law (although I do realise it is the norm to just put it on anyway)?

        1. Hi Brian – yes, I absolutely appreciate “may contains” are completely voluntary and you are never sure whether the risk is genuine, or if a manufacturer is covering itself (I talked about it here: https://www.nutmums.com/uk-food-allergen-labelling-law/). However, I don’t look behind a “may contain” label. I take the manufacturer at their word. If a product says “may contain nuts”, for me, it doesn’t get as far as the trolley. For most types of food, there tends to be a nut safe option available – although it might take a little more time searching!

  10. A very interesting article – my 5yr old son has recently been diagnosed as being allergic to all nuts and we too avoid foods that carry the warning ‘May Contain’. However, on hearing that it is a voluntary label and manufacturers do not need to print info on possible cross-contamination, how can i then trust foods that do not have any May Contain info – this would practically rule out all foods in supermarkets. Another scenario, if the product states ‘may contain Celery’ only, can i assume it is nut-free.
    Are there any food products that state ‘nut-free’ which would be much more reassuring.

    1. Hi Vicki – I know – it’s a minefield! I talked about this in my post about Oreo (https://www.nutmums.com/may-contain-nuts-oreo/).

      In short, if I’m faced with a “silent” product, I contact the manufacturer for more information. I would tend to assume if something says “may contain celery”, but doesn’t say “may contain nuts”, that it’s probably safe. But that may be risky logic (see the Oreo post!).

      There are some “nut free” products out there – but they’re not common and can sometimes be pricey, as my understanding is that manufacturers have to go through various extra hoops to be able to positively state something is “nut free”. I’m planning to cover this in detail in a post very soon.

      If you’ve not already seen it, you might want to have a look at the nut free food directory (https://www.nutmums.com/nut-free-food/) – which includes some dedicated nut free brands.

  11. What’s your thoughts on school bans on products that “may contain nuts”? We have a child at our school with a severe nut allergy, and the school has rightly banned nuts / food containing nuts. However they have now started to stop children bringing in food that is labelled as “may contain nuts”. Is this a sensible move or an overreaction from the school? I can see the argument both ways, and I believe the parent of the affected child is OK with parents giving their children food labelled “may contain nuts”, and that the ban is due to the school only

    1. Hi David – interesting question! Outside school, I would move my son away from another child eating a peanut butter sandwich or a nutty biscuit, but I wouldn’t if it were a biscuit labelled only “may contain nuts”. I’m happy that our school bans nuts and nut containing products and has a no swaps rule. I wouldn’t expect them to ban may contains too. That’s just my opinion though! – happy to repost your question on the Nutmums facebook page (www.facebook.com/nutmums) to canvas other nut mums’ opinions on this – just let me know if you’d like me to do that.

  12. I also suspect the reason we are less likely to have a reaction compared to being struck by lightning or murdered is because we try so very hard to avoid peanuts, nuts, may contains etc. If all of us followed the flippant advice to eat may contains etc, I think the numbers would be sadly higher.

  13. Could I ask a question as someone who is new to the nut allergy situation. I have Coeliac disease which means I avoid all gluten including may contain but if there is nothing like that in the ingredients I would use that product. But with nut allergy, if there is NO may contain, or NO nuts in the ingredients would you still use that product or would you still want assurance from the manufacturer for example. My experience so far is that virtually no manufacturer once I have contacted them about nuts, even though there is nothing on the label to suspect nuts in the product, they will still not guarantee nut free as their “supplier” will not guarantee nut free ingredients.

    1. Hi Jennifer – thanks for your message. For me, it depends what I know about the brand already – if I pick up a product with no may contain label from e.g. Kelloggs, then I would think the product was safe (because I’ve been told by Kelloggs that IF there is a risk of cross contamination, they would use a may contain label – so if the label’s silent, I would assume it’s safe). If it’s a brand I’d not come across before, and I didn’t know their approach to may contains, I would maybe have a look at their website, or email their customer services. Very few brands actually come out and say their product is “nut free” – even brands like Kinnerton and Just Love Food Company only make a “nut safe” promise. So maybe ask “do you use a may contain label, if there is a risk of cross contamination” rather than ask if something’s nut “free”? That’s just my take on it though – just let me know if you’d like me to post your question on the Nutmums facebook page, to see what others think. Louise

      1. PS. Realise Kelloggs not most helpful example for you – but I’ve been told the same from e.g. Dolmio and DS Gluten Free. (If you are ever trying to find a gluten and nut free version of something, always feel free to post on the FB page – someone there might be able to help). Louise

  14. hi it’s a total nightmare. I think if manufactures got together and had a nutfree factory it would help everyone. This problem is getting worse. My son has suffered from 2years and he is now 24years and moved in with his partner. I now have to live in hope they read everything as I have to take a step back. He also has a slight allergy to sesame seed and Asma Shorly they could share a factory. My son travels abroad and selfishly it make the time they are away my second worst nightmare. Always worried mum.

  15. I am anaphylactic to nuts, wheat and apples. As Apple is not in the top 8/9/10 allergens (depending on where you live!) it is never declared as a may contain however I have to avoid all things which contain fruit where I do not know what fruit. As for nuts and wheat, I avoid any food that may contain peanuts, tree nuts, nuts, gluten, wheat or gluten containing cereals! Amazingly there is still quite a variety of food that I can eat but sometimes it can be difficult and fresh is always best!

    1. Hi Hanna – that must be even trickier avoiding something that’s outside the “top” allergens. I know one mum had to scan labels for pea starch – which was sometimes just described as something vague like “other flavourings”. Glad you can still find a safe variety. Thanks for posting, Louise

  16. I am allergic to tree nuts and related fruits, wheat, beef, etc. I used to ignore “may contain” labels until I started to get reactions from energy bars (Cliff Bar and Kashi for sure). Maybe the mixing machine they use to make energy bars are hard to clean completely between batches. I am fine with giving up energy bars but it will be tough to give up on chocolates. I wish they had better warning labels.

  17. There is a company in the US called Vermont Nut Free that make delicious chocolates and granola bars. Have used them for years.

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