Ralph Cator

LifeStudies
Challenge and Shelf
Testing for the worst-case scenario, and pushing the limits of your
food product.
By Dawn Van Dam
D
etermining how your
product reacts to microbial
contamination and confirming
shelf life provides invaluable information
to the food industry in terms of product
quality and safety. Challenge and shelf
life studies provide this information by
evaluating a product over the course of
the intended shelf life.
Challenge studies
Drills are an essential component
of safety; fire drills, lifeboat drills, CPR
drills...their merit is unquestioned. The reason: learning
how to deal with the worst-case scenario – safely. Challenge
studies are of the same nature. They allow food producers
to reduce risks to food safety by preparing for the worst-case
scenario.
Challenge studies are similar to shelf life studies in that
they examine how microorganisms in a product change
over time. The main difference is that in a challenge study
the product is purposefully inoculated with pathogens,
simulating a chance contamination.
There are two types of challenge studies. The type
known as an inactivation study determines the ability of a
processing step or formulation to ‘inactivate’ the growth
of pathogens of concern (pathogens that historically have
been identified as a risk for a certain type of product). For
example, physical processes such as heating, irradiation and
high pressure treatments can ‘inactivate’ pathogens in a
product.
The other type of challenge study is called an inhibition
study. This type of study confirms the success of a specific
formulation and/or packaging strategy in inhibiting
the growth of pathogens of concern. For example, the
application of sodium acetate or diacetate has been shown
to inhibit the growth of listeria during post-processing steps.
For products like ready-to-eat meats, the application of
antimicrobial additives can decrease the risk to consumers.
So, with challenge studies you can determine how well
your product stands up against microbial contamination.
Shelf life studies
While challenge studies address the issue of chance
contamination, shelf life testing determines the length of
time that a food product will maintain its quality before it
begins to spoil.
As a means of providing consumers with the most reliable
information about the lifespan of a product, and as a measure
of the success of your shelf life-extending strategies, these
studies provide invaluable information to the food industry.
Consumer preferences have shifted towards labels such
as ‘no additives or preservatives’ or
‘no sugar/sodium added.’ The food
industry is continuously looking for
new ways to preserve the freshness and
quality of food over an extended period
of time without the addition of such
additives. Shelf life studies evaluate the
efficacy of new technologies/methods
for extending shelf life, so you can
maintain product quality while adapting
to consumer demands.
Periodic reexamination of shelf life
can also determine if changes made
in your manufacturing process, such as new materials or
suppliers, or new equipment or formulations have affected
the microbiological profile and changed the shelf life.
Shelf life studies are not simple step-by-step procedures;
they rely heavily upon the experience and expertise of the
scientists involved. Each individual shelf life study must
be designed to reflect the unique conditions of a product
including pH, moisture and temperature. Microbial
examination is then conducted over the course of the
intended shelf life, or even beyond to determine the point of
spoilage. Ultimately, consumers use their senses to determine
whether or not a product is desirable, but microbial growth
can reach unsafe levels before any unpleasant changes are
noted.
Evaluating shelf life can help you identify and minimize
risks, determine the most effective methods to prolong your
products’ freshness or marketability, and provide information
to consumers about the lifespan of your product.
University of Guelph
The University of Guelph, Agriculture & Food Laboratory
(AFL) offers customized studies that provide reliable results
and information on how your products react to microbial
contaminations, and how to confirm the shelf life of your
products. When it comes to protecting consumers and brand
names, accurate results are paramount. The AFL is supported
by an integrated quality management system that achieves
the ISO 9001:2008 and ISO/IEC 17025 international quality
standards as well as for specific tests listed on our Scope of
Accreditation, and is happy to work with you to customize
studies, providing the scientific support you need to have
peace of mind.
For more information about conducting shelf life or
challenge studies, you can reach AFL at 519-767-6299 or
1-877-863-4235 (1-877-UofG-AFL), or through email at
aflinfo@uoguelph.ca.
Dawn Van Dam is the Chief Marketing Officer for the University of
Guelph, Laboratory Services, Agriculture & Food Laboratory.
16 Canadian Meat Business September/October 2010 meatbusiness.ca