Two significant risks are bacterial contamination (e.g., Salmonella, E. coli) which can cause severe gastrointestinal illness in the pet and zoonotic transmission to humans, and nutritional imbalances if the diet is not properly formulated, potentially leading to deficiencies or excesses of critical nutrients that harm bone development, organ function, or overall health.
Instead of raw diets, I would recommend high-quality commercially prepared kibble or wet foods that are specifically formulated to meet AAFCO standards for cats or dogs, ensuring they are nutritionally complete and balanced. Alternatively, for clients seeking a more "natural" option, I could suggest cooked homemade diets, provided they are carefully formulated by a veterinary nutritionist to be balanced, or recommend carefully vetted commercially available fresh or gently cooked diets.