Sous-Vide shrimp, minimum time and temp for safety?
From Douglas Baldwin's sous vide guide :


  Fish intended for immune compromised individuals or for cold holding (i.e., cook-chill) should be pasteurized for at least the times in Table 3.1 (to achieve 6D reduction of Listeria monocytogenes). While such a pasteurization will reduce all non-spore forming pathogens and parasites to a safe level, it will not reduce the risk of HAV or norovirus infection from shellfish. Since a 4D reduction of HAV in molluscan shellfish requires holding at an internal temperature of 194°F (90°C) for 1.5 minutes, the risk of viral contamination is best controlled through proper sanitation and hygiene (National Advisory Committee on Microbiological Criteria for Food, 2008). Since the spores of non-proteolytic C. botulinum are not inactivated by pasteurization, the fish should be stored at below 38°F (3.3°C) for no more than three to four weeks.


And then gives tables for pasteurization.  I'd assume it'd fall under 'lean fish' if we assume that shrimp and fish are similar (as only crabmeat is singled out in the FDA's Fish and Fishery Products 
Hazards and Controls Guidance), and use the value for the temperature desired and the size of the shrimp at their widest point.