CFU/g. For either organism to apparently
cause illness, required levels in foods are
about 1 × 105 CFU/g. 4, 5 To help our operators make conservative decisions until the
information can be reviewed by a processing authority, we use the time it takes for
S. aureus or C. perfringens to increase by 2
logs at the maximum growth temperature,
plus a reasonable lag period. The models
cited predict this is at least 2. 5 hours. This
means that product that is exposed to
suboptimal cooking temperatures for 2. 5
hours or less is safe to then continue cooking, as insufficient time has elapsed for enterotoxin formation or generation of high
enough numbers of C. perfringens spores
to cause illness. If the interruption to
the cooking process lasts longer than 2. 5
hours, then product must be put on hold
after cooking and chilling are completed
for a process authority to review the data
and, when necessary, conduct end-product
testing for staphylococcal enterotoxin or
C. perfringens counts to determine product
disposition. Consideration should also
be given to organoleptic deterioration of
product through either spoilage organism
growth or excessive heat effects.
Case 3. Loss of Refrigeration
No matter what type of food product is
being produced in a facility, refrigeration
is a significant component of the food
safety and quality process. Depending on the situation, interruption of refrigeration
caused by a power outage or breakdown of the cooling system may occur, affecting
a single department/area or the entire processing plant. Although backup genera-
tors with the capacity to operate critical equipment such as refrigeration and freezer
units, pumps and safety lighting are lifesavers, in most cases, these function strictly
as a short-term substitute. An interruption in refrigeration may lead to the growth
of spoilage organisms, pathogens and toxins in products that normally are under
temperature control. For instance, inadequate cold storage or cooling can allow
spores of Clostridium botulinum and C. perfringens to germinate, resulting in vegeta-
tive cells multiplying to hazardous levels. Both organisms will grow in the range of
10–46 °C (50–115 °F) and produce heat-resistant spores. S. aureus is another patho-
gen of concern that produces a toxin when growth is not controlled by adequate
refrigeration. Rapid growth of spoilage organisms during this inadequate cooling
period will lead to detrimental product quality and sensory issues.
We have facilities that produce both fully cooked items and some that have no
kill step in their processes. In either case, their incoming ingredients are often tem-
perature sensitive and must be kept below 7 °C ( 45 °F) during storage and processing
to prevent outgrowth of pathogens and spoilage organisms. If loss of refrigeration is
limited to a single room or area, we first assess how long the area, and more impor-
tantly the product, will remain below 7 °C if left undisturbed. If refrigerated items
are in large totes or vats, or stacked on pallets, they will hold temperature for a long
ate Hazard Analyses can be completed.
If temperatures remain above 52 °C
(we use a conservative figure of 54 °C),
neither pathogen will grow and will
probably lose viability, so there is no
risk to product safety even though it
has not yet reached the CL. If product
temperatures are below 52 °C during
the downtime, then growth of either
pathogen to hazardous levels may occur
given sufficient time.
We need to make some well-founded
assumptions at this point, because we
normally lack adequate information
concerning initial levels of pathogens
and their growth responses to changing
and unknown temperatures. We have
conducted many internal studies measuring the prevalence of S. aureus and C.
perfringens in our raw meat and poultry
materials and have never measured
either organism at higher than 5 × 102
Figure 1. Decision Tree for Batch House Cooking Failures
Cook system failure, power outage or mechanical failure.
Cook system operator reports failure to supervisor.
Operator records time of failure. Records four product temps.
Restore cook cycle. Record four product temps prior to restart.
temps ≥ 54 °C? Outage
lasts ≥ 2. 5 h?
Continue to cook until CL is met.
Chill product and put on hold.
Record all observations.
Review with process authority
for product disposition.
Release product to chill.
Continue to cook until
critical limit (CL) is met.