I think Timothy Shame will find that biological samples (urine, for example) are typically stored by laboratories at -80 C or under liquid nitrogen (which boils at -196 C), and that frost-free fridges (as he evidently has at home) are deliberately not used due to the temperature cycling (forgive the pun) required to, wait for it, keep them "frost free".
http://us.rd.yahoo.com/dailynews/rss/search/bicycle+racing/SIG=11s9o5t13/*http%3A//www.cyclingnews.com/letters/?id=2005/12-02letters
http://us.rd.yahoo.com/dailynews/rss/search/bicycle+racing/SIG=11s9o5t13/*http%3A//www.cyclingnews.com/letters/?id=2005/12-02letters