The issue regarding toy reward versus food reward is jostled about from time to time, and I find it rather perplexing to think that one method is so much better than the other. 

Having been involved with the training of hundreds of bomb and drug dogs earlier in my career the only method I was familiar with was toy reward training for detector dogs.  However, once I became increasingly more involved with working with the smaller breeds it was apparent that a lot of great dogs would never have the opportunity to do scent detection work due to their lack of “Toy Drive”, but still loved to hunt and apply their nose accordingly.  Many of these dogs did not have any interest whatsoever with toys, but would do anything for food.  This is where all the “Toy Reward” people of the world must understand that by insisting on toy reward dogs they are eliminating a lot of super dogs.

My preference would be toy reward dogs in a perfect world, but the fact of the matter is a lot of dogs, even with toy drive, are not as consistent throughout a busy day for a toy as they are for food.  Many do not realize that most police detector dogs are in a patrol car most of the night and may get used here and there for a search.  This is where a toy works very well.  A bedbug detector dog may be asked to sweep an entire hotel in a single day.  This is where proper motivation becomes vital.  Some toy reward dogs become disinterested after a lot of work.

There are many skeptics who claim food reward dogs are the cause for many “false positive” alerts.  The fact of the matter is that with proper training and handling a food reward dog is just as reliable as any toy reward dog, maybe more.  You have to continually proof off of tennis balls, rubber and food the same with a toy reward dog as you do a food reward dog.  The argument is preposterous. 

I would agree wholeheartedly with the toy reward advocates in the event somebody was starving their dog to work harder, but that simply is not the case with most.  A dog with excellent food drive can work all day even after being fed and still wants to work more because of their love of food.  They are fed the same as any other dog it’s just that they will do anything for food the same as a dog that does tricks or obedience for food.  It is totally motivational and that is the name of the game. 
There is a reason the ATF, Customs, and the USDA use food reward dogs almost exclusively.

Without proper motivation a working dog simply will not work at all or as consistent as it should.  I have seen toy reward dogs that simply did not work as well for the toy as they did for food and switched them to food to find them to work very well.  I have also seen toy reward dogs work exceptionally well.  Dogs have varying degrees of genetically acquired subconscious compulsions and characteristic traits that may be perfect for a particular task, but finding the motivation that makes them perform better can be drastically different from dog to dog.