Here in the link to the CDC report.
it's not just Zika that can be transmitted via blood: So can other mosquito linked viruses such as dengue and west Nile virus...And of course Hepatitis B, C, etc. and HIV (although modern screening methods detect these so the blood is safe).
one way is to limit blood from areas that don't have the virus, and not to take blood if you have been in an area with the virus (Mainly Puerto Rico right now). Alas, there was no good screening test until recently, but now one is available:
so presumably the blood supply is safe.
On April 3, 2016, Zika virus screening of locally collected blood donations was implemented using a newly developed nucleic acid test (NAT) (cobas Zika, Roche Molecular Systems, Inc., Pleasanton, California) authorized by FDA under an investigational new drug application (IND) (6). As part of the IND, plasma samples from blood donors are screened individually, and specimens with reactive results are subjected to additional testing including an alternate NAT and immunoglobulin M serology. A blood donation with an initial reactive result by NAT is regarded as a presumptive viremic donor, indicating an infected donor, and is interdicted and removed from the blood supply.
Currently, no medication or vaccine is available to treat or prevent Zika virus disease. Prevention relies on avoidance of mosquito bites, elimination of mosquito breeding sites, community mosquito control, and taking measures to prevent sexual transmission. Screening of the U.S. blood supply using nucleic acid tests has markedly reduced the risk for transfusion transmission for multiple pathogens, including for West Nile virus after it was associated with arboviral epidemics in the United States.