Full text
PDFPage 671
. 1986 Mar;51(3):671. doi: 10.1128/aem.51.3.671-671.1986
Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.