During WW II, the Army decided to train dogs for war purposes.  With use in the Pacific in mind, some Nisei soldiers from the 100th Infantry Battalion were voluntold for a secret assignment to play the role of Japanese infantry.  The Army figured that they had the same genes as the mainland Japanese and would therefore smell alike.  Never mind the American hamburger diet or other things the Nisei ate at the mess hall.  After all, they were Americans too.

So the Nisei were sent to Cat Island, Mississippi to play the Japanese whom the dogs were trained to track and attack.  While war dogs were trained and deployed in both the ETO and PTO and there were never enough, the training on Cat Island was a failure.  Read more about it at this National Park Service link:

https://www.nps.gov/articles/japaneseamericans_cat-island.htm

The Marines also had war dogs and the First War Dog Platoon was trained by a Hollywood trainer.  The 2nd and 3rd were trained by a veternarian turned commissioned officer at Quantico.  They had much more success and part of it was their careful screening of dogs.  You can read about it (via interlibrary loan if you want to save ducats) in Lt. William Putney's Always Faithful.  Capt. Putney (the veternarian) commanded the 3rd War Dog Platoon.

I believe Koehler was involved in setting up the training for the War Dogs.

I know the Japanese used GI soap, cigarettes and any rations they could find to avoid detection.