I recently had someone tell me they used their oven to can green beans. Shouldn't you use a pressure cooker ?

I believe Europeans occassionally use the oven for canning - it's one of the methods detailed in the new River Cottage Preserves Cookbook. Not considered safe in the US, and especially not with low acid foods like green beans. I've had marginal success pressure canning green beans, with the exception of pickled (dilly) beans. IQF seems to retain color & crunch more consistently.