protecting your purchases
Hi Ingemar,
During my last visit in Scandinavia (Fall 2009), much of my "souvenir shopping" occurred in a supermarket. Two boxes of Via, but also coffee and various other Swedish food items (nonperishable) that are not available in USA. In particular, friends and relatives enjoy the coffee and other food items as gifts/souvenirs.
IKEA stores in USA have small Swedish markets with a limited selection of specialty foods, but not all brands are represented. A brand's representation seems to depend on whether fees are paid to IKEA.

For example, IKEA stores sell only one brand of coffee, and that brand (Löfbergs) is considered by my Swedish friends to be an "also-ran" (not outstanding, just average, and I've never seen it used in anyone's home in Sweden). There are better brands that cost about the same, but you never see them for sale at IKEA.
That said, I packed the coffee, Via, and other products in my wheeled duffel bag. It was raining heavily both in Stockholm and in New York (where I transferred to a flight to California). The luggage was outside on the tarmac both in Sweden and in New York. It may have been exposed to heavy rain in one or both airports. Immigration/customs regulations in USA require that you pass through immigration/customs in the FIRST city in which you enter the USA ("port of entry"). You claim your bags in the first US airport (New York, in this case), pass through customs, and then you give your bags back to the airline (very simple, there is a counter just beyond customs and you simply give your cart and its bags to an attendant), and proceed to the next flight gate. However, this means the bags were unloaded off an aircraft, brought into the terminal, and then loaded onto a second aircraft. I don't remember the bags being soaking wet in customs, so they may have become wet while being moved to the next aircraft.
When I arrived home, some of the cardboard boxes were moist (not ruined, but almost). Fortunately, the food items had plastic inner liners inside the paper or cardboard cartons, so they were safe. One of the Via cartons was moist (but not soaking wet) and I was able to save the Via by pouring it into a plastic tub with airtight cover. Fortunately the Via was still dry and powdery.
Lesson of the story: don't just pack your purchases in your suitcase. Place them in a protective plastic bag. In USA, you can find one or four liter (one gallon) bags that would have accommodated the items I brought home, and would have kept them dry. A hard suitcase provides more protection, but it's not guaranteed to keep things dry. Another option would be to bring items like detergent in your cabin baggage to keep them dry.