This is in their FAQs about cross contamination. I have given their products to my kids when there are no warnings, but I think it is interesting how they state it.
Our production lines are thoroughly cleaned between allergen containing
products and we follow good manufacturing practices. We have validated
(through testing) our allergen cleaning processes in all of our
facilities. We are very concerned about food allergies and want to
ensure that our products are safe for food allergic consumers to eat.
Scientific evidence has shown that consumers with peanut and tree nut
allergies can have a severe reaction to amounts that are below the
current detectable limits based on existing technology. For this reason,
we have chosen to warn consumers allergic to peanuts and tree nuts of
the potential for extremely low levels by using a may contain statement.
For all other top 8 allergens - if the product contains the
allergen, it will be listed below the ingredient statement. If it is not
listed below the ingredient statement, we are confident that the
product is safe for consumption. Please trust the labeling and continue
to check it for any changes.
Re: Do you trust Kashi?
Personally I would trust Kashi. The company is very much dedicated to making healthy, organic food and is one of those that was into sustainability a long time ago. Since people who are vegetarian (maybe even vegan?) and those with food allergies more than likely look for the brand, I think they'd probably be overly cautious about their ingredients lists and cross contamination warnings.
I guess I would probably heed their warnings... Are you concerned about their products?
We don't. But mostly because we don't consume very much processed food. I heard a week or so ago that they had a large recall due to plastic particles found in their food. I didn't pay it much attention since we don't eat it but found the link for you:
https://www.huffingtonpost.com/2011/06/07/kashi-recalls-pizza-plastic_n_872560.html
52 Choices For Better Health