Is my product safe?
This is a tricky one to answer – we can never categorically say that a product is safe, all we can do is say what organisms it has been tested for and what the results are.
If we test a food for e.g. Salmonella, we take a small 25g portion of that food to test – it would be impractical to take the whole of the food item. If the test is negative then we can say that Salmonella was not detected in 25gms, which is the level of reporting that is generally required. However this does not guarantee that there was no Salmonella in the portion we did not test, or in other products from the same batch, because bacteria may not to be evenly distributed through the food and will be more concentrated in places where they are multiplying.
So with conventional testing we can say that from a particular food product we have not detected Salmonella, Listeria, E. coli O157, Campylobacter, Clostridium, Staphylococci or Bacillus, which is an acceptable result.
However we can never actually say that a product is safe because there is always the chance that there is something present that we have not tested for. We cannot test for viruses or parasites on a routine basis, and would not be looking for poisonous chemicals or toxins. So while we can report what was not detected, we can never make a statement that a food is safe. All we can do is eliminate the most predictable risks.