How to pass Saucelabs Username and AccessKey in Testcafe to execute tests on cloud

Am new to TestCafe, as per documentation I have created two environment variables in my system [SAUCE_USERNAME, SAUCE_ACCESS_KEY] as they suggested and passed Saucelabs username and Accesskey. After that am running below command

"testcafe "saucelabs:Chrome@beta:Windows 10" tests/SmokeTest.js"

We keep on getting authentication failed error message and I can see below file getting generated.

"2020-08-25 05:55:39.838 [9464] Sauce Connect 4.6.2, build 5183 ad61662 2020-08-25 05:55:39.838 [9464] Error, no user specified."

When am trying to get the values using process.env['SAUCE_USERNAME'], am getting variable is undefined.

Can anyone help us here