It IS a refrigerated trailer...note the style of flooring which is common to nearly all reefer trlrs. CA license plate?
I can tell you from having hauled my fair share of meat that this isn't the accepted method..meat packing plants and food processing plants are notoriously picky about the conditions of transport, cleanliness of trailers and seals, temp control, etc. Believe it or not, pet food processors are the most picky!
This may be OK in most 3rd World areas, but not in the US, and DEFINITELY NOT in the DPRC.