What I do is use many of the plastic containers for freeze containers. I just fill them mark them and when I take them out of the freezer I just run them under hot water...or let them thaw a while...then I put the contents in a bowl and zap in the microwave.
If the Campbell web site has a "contact us" link you can pose your question to them via that. Otherwise, I would go ahead and use it. Because of the plethora of lawsuits in this country against large corporations, many "instructions" that come with a company's products are there solely to protect the corporation from a potential lawsuit (and you can't blame them).
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