The cheese that dropped is one of the safer ones
Of all the foods that might tumble from a salad board, a cube of plain mozzarella is among the least worrying for a dog. Mozzarella is a fresh, mild cheese, and because it is not aged for long it generally contains less lactose than many dogs struggle with, alongside a moderate rather than extreme salt level. That does not make it a health food for dogs: it is still a fatty, calorie-dense dairy product, and plenty of dogs have some degree of lactose intolerance regardless of the cheese. The fair verdict is that a small cube or two is a fine occasional treat for most healthy dogs, offered plainly and without making cheese a daily expectation.
Fresh mozzarella versus the processed kind
The cube from a salad board is usually fresh mozzarella, which is the better version for a dog: soft, plain, and free of flavourings. Be more cautious with processed mozzarella products, which can carry extra salt, oils, and in flavoured varieties garlic or herbs that do not belong in a dog's bowl. If the board also held marinated mozzarella, keep that for people, because the oil, vinegar, chilli, and garlic it soaked in change the picture. Whatever the type, cut large cubes down for small dogs, since a soft cheese cube swallowed whole and fast can gag a dog who treats every dropped morsel as a race.
Portion sense for a dairy treat
One or two pea-to-cube-size pieces are a treat; a handful scattered across the board is a stomach ache in waiting. Cheese calories add up quickly for small dogs, and rich dairy is a common trigger for soft stools and wind, so keep mozzarella to now-and-then status rather than folding it into daily training rewards. Dogs who are overweight, prone to pancreas flare-ups, or known to react badly to dairy should skip cheese entirely in favour of a lean protein treat or a piece of their normal food used as a reward. If this is your dog's first cheese, give a single small cube and let a day pass before deciding it suits him.
Reading your dog's dairy tolerance
If mozzarella becomes a planned treat rather than a board accident, buy the plain fresh kind and cut cubes at home rather than reaching for string cheese or grated blends, which are processed for melting and often saltier. A single cube tucked into a puzzle toy or used as the final reward of a training session stretches its value far further than scattering several across the floor during salad making.
The signs that mozzarella does not agree with a particular dog usually appear within a day: loose stools, noticeable wind, a gurgling stomach, or itchy skin that flares after dairy days. Those signs mean cheese comes off his treat list, not that he needs a bigger test portion. Contact your vet if vomiting or diarrhoea persists, if a dog with a sensitive stomach seems uncomfortable for more than a day, or if he helped himself to a large quantity of rich cheese from the board rather than a single dropped cube. Recording which treats your dog handles well in KinsLe through Care Teams gives everyone preparing his food the same picture, so a tolerated occasional cube stays exactly that.