If you check the ingredients list you'll find they don't use many preservatives because there is little need, and so use of them would just increase costs. The

If you check the ingredients list you'll find they don't use many preservatives because there is little need, and so use of them would just increase costs. The ingredients you've bought and put in the fridge are no more or less likely to use preservatives than the ones that go into a supermarket sandwich. The cost and ability to make it your own in terms of ingredients is a good reason to make your own, but the preservative argument? That doesn't make sense to me.