As the article states, exposure to peanuts as an infant prevents the allergy. Treatment for allergy is to gradually introduce peanuts. A little bit of peanut butter on a shopping cart could potentially prevent the allergy from developing.
Being a dog person, this reminds me of one of the many good reasons for having one or more large dogs if one has kids. Dogs, being dogs, are inherently septic creatures. Kids who play with them pick up all sorts of bugs that give the kids mostly minuscule infections that the kids' immune systems easily overcome. That gives the dog kids stronger immune systems than the non-dog kids have and makes the dog kids healthier. Included also is that the dog kids are happier because they have wonderful, big, four footed friends.