Excerpts from the report: Loads of seed potatoes have been rejected at destinations in potato-growing areas by receivers when some of the bags contained potatoes frozen in transit. Some receivers believe that if part of a lot of potatoes is frozen, the remaining potatoes are damaged and unsuited for seed even though no visible symptoms appear. If unwarranted, this rejection is unfair to shippers and carriers. It also inconveniences receivers and growers who must find other lots of seed to plant. If justified, protective practices can be adopted by shippers, carriers, and handlers to provide temperatures well above freezing. Since previous reports are contradictory, large-scale tests were undertaken to get information on cooling, supercooling and freezing injury of four varieties of potatoes commonly used for seed.