PET Food Processing - September 2020 - 31

FORMULATION

JUST
ENOUGH
A look at the importance of managing
moisture and water activity in pet food.
By Keith Loria | petfoodprocessing@sosland.com

W

Water is a vital component of pet food but there is a science to making sure there's enough and not too much.
In fact, properly managing water activity in pet food and
treat production not only ensures safe, quality product,
but also maximizes profits.
"Managing water activity is the most important
monitoring tool that can be used for pet food safety and
quality," said Brady Carter, Ph.D., senior application
scientist, Neutec Group, Inc., Farmingdale, N.Y. "Many
manufacturers have moved to releasing product based
on water activity alone."
The key to maximizing the shelf life of pet food is to
identify the ideal water activity range, not only in terms
of microbial growth, but also for chemical degradation
and texture.
"Through experimentation, the ideal water activity
range with both a lower and upper limit can be identified where the product has all the desired characteristics and the longest shelf life," Carter said. "Once established, production performance and efficiency are all
monitored through water activity testing in the QA Lab
to make sure all product falls into the established water
activity specification."
There are many issues that can result from a faulty water activity, including: bacterial growth, mold, rancidity,
process bridging, poor extrusion with improper mixing, kibbles sticking together and, in the case of too-low

water activity, the products become dried out and/or too
solid to be edible.
The amount of water can also have an adverse effect
upon the health of a pet; not enough causes hard or dry
pet food and too much moisture can make the food soggy
and can cause the food to mold, sour or become spoiled.
Sarah Hammond, marketing coordinator, MoistTech
Corp., Sarasota, Fla., noted maintaining the proper
moisture level throughout the production process minimizes waste and maximizes product quality.
"Monitoring the moisture in the raw materials, controlling the mixing/blending process and moisture of the
feed in pellet form not only ensures an end-product with
consistent quality, but will enable substantial savings to
be achieved in the production process," she said. "The
user will know the levels of moisture in the raw material and will be able to accurately calculate the amount
of moisture that needs to be added to the mix to achieve
the correct consistency of the end-product."
Brock Lundberg, Ph.D., president of research and development and applications, Fiberstar, River Falls, Wis.,
agreed that controlling moisture and water activity in
pet food is critical and directly impacts both shelf life
and palatability.
"In semi-moist pet foods, if the water activity is too
high without a proper preservation system, the product's shelf life will need to be relatively short," he said.

Properly managed
water activity
prevents liquids
from separating
from solids in wet
pet food and helps
maintain product
consistency.
Fiberstar

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