TESTING
By William H. Sperber, Ph.D.
Shifting the Emphasis
from Product Testing
to Process Testing
To test the process or test the prod- uct? This question reminds me of the riddle that has probably been asked for
thousands of years—“Which came
first, the chicken or the egg?” Thanks
to evolutionary biology, we know that
the egg came first, by several hundred million years. However, the
answer to the “test the process or test the product” question might
never be so clear. I think today we must answer, “Both.” There are
times when it will be better to test the process, and other times when
it will be better to test the product.
It could also be necessary to test both, or neither. In the modern food industry,
product testing preceded process testing as a means to evaluate or assure food
safety. For that reason, there remains today an undue reliance, even insistence,
upon product testing. This article will discuss testing processed food products, raw
foods and uncooked, ready-to-eat (RTE) food products as well as the process, and
shifting the emphasis from product to process testing.
Testing Processed Food Products
In the 1960s, the National Academy of Sciences (NAS) and the International
Commission on Microbiological Specifications for Foods (ICMSF) attempted to
establish procedures for food safety evaluation by organizing and publishing a
wide array of microbiological criteria based upon product testing. I will mention
just two of the original reports here. They are the following:
• NAS/NRC. 1969. An evaluation of the Salmonella problem.1
• Microorganisms in foods. Book 2. Sampling for microbiological analysis: Principles and specific applications. 2
These publications include hazard
and risk categories, microbiological specifications and product sampling plans.
This is where n = 13, 15, 30 or 60 originated. It must be pointed out that these
procedures were developed for the
analysis of materials of unknown origin
and unknown means of control—for example, for materials that could have
been procured at any point in the global
supply chain—or they were used to evaluate acute problems such as Salmonella
in dried eggs in the 1960s, just as today
we might evaluate an acute problem of
Salmonella in nut products. In the absence of information about the process,
product testing is the only means to
evaluate food safety, even though we
know it doesn’t work very well.
Product testing for food safety is unnecessary today when processed foods
are of known origin and produced under
known means of control. The major advance in this area was the introduction
of the Hazard Analysis and Critical
Control Points (HACCP) system of
food safety management in the 1970s,
with the later recognition and accepted
use of prerequisite programs. HACCP is
a preventative system designed to control significant identified hazards by
means of validated process control
measures. It does not depend on product testing to assure food safety. In fact,
HACCP was developed precisely because product testing cannot reliably
detect low-level defects, such as low-incidence pathogen contamination in
foods.
The application of HACCP is best
epitomized by the canned food regulations that were developed in 1973. Based
upon HACCP, finished-product testing
of canned foods is not required and not
necessary when the requirements of
these regulations are met. 3 A similar
food-processing application preceded
HACCP and the canned foods regulations by 50 years—the first publication of
the pasteurized milk ordinance (PMO)
in 1923. Scientists and regulators back
then learned that the safety of dairy
