Official information request details
Official guidance documents we use in New Zealand to cover the handling and transportation of microbiology samples from provincial hospitals to centralized testing laboratories.
I expect that official guidance would cover aspects such as reported by Miller et al.  including transport media, temperature and time from specimen extraction from patient until the analysis is completed at the centralized laboratory.  Miller et al., A guide to utilization of the microbiology laboratory for diagnosis of infectious diseases 2018: Updated by the Infectious Diseases Society of America and the American Society of Microbiology. Current Infectious Diseases 2018, 67(6), e1-e94. doi: 10.1093/cid/ciy381.