We recently bought some soy milk for my 14-month-old son (who had previously been allergic to both milk and soy, among other things, but seems to have outgrown the soy allergy!). We bought WestSoy and the box says it's only good for 5-7 days in the fridge once it's been opened. Is this really true? If so we will be wasting a lot as he only drinks a bit at once, especially while getting started. We have it in a rubbermaid container as the plastic cap broke off, so maybe that will help? Are all the brands the same, as far as "fridge-life" goes? The other boxes I saw didn't give any indication. Thanks, --Robyn