Thirty-one samples collected 3, 8 and 13 months after production
were analyzed to check them for shelf life. For the 24 samples
collected after 3 months, 7 had the same composition (species and
numbers) as those collected from the manufacturer. After 8 months,
from the 6 samples collected, only 2 had the same composition
(species and numbers) as those collected from the manufacturer.
Finally, after 13 months only 1 sample had the same composition as
that from the manufacturer.