The most common reason is because he raw food is not being digested properly. Best solutions are to switch off a diet rich in red meats like lamb and beef, and choose simpler proteins like chicken, turkey, duck and rabbit more frequently.

2nd consideration is to try adding a digestive enzyme into the diet to see if this helps break down food quicker and more effectively resulting in better breath, and 3rd is to add hot water or offer the food at room temperature to help speed up the digestive process.

Normally 1 or 2 of these suggestions is the fix.