meat and poultry samples analyzed by a method that had no prior heating step to
destroy the vegetative cells, so the number of spores could not be differentiated and
the colonies were not confirmed to be C. perfringens (RB Tompkin, personal communication). This led to very conservative time and temperatures being required for
cooling in the 1999 version of Appendix B (i.e., no greater than a 1-log increase in
C. perfringens). Several industry studies were subsequently published clarifying spore
levels in raw meat and poultry samples, demonstrating growth control in actual meat
and poultry products during extended cooling and die-off of vegetative cells of C.
perfringens during subsequent refrigerated storage.
7–9 Indeed, the USDA risk assessment concluded that C. perfringens growth during stabilization of RTE or partially
cooked (PC) meat and poultry products has a small overall effect on the likelihood
of illness, and that growth during retail and consumer storage is the major predicted
cause of illnesses from C. perfringens in RTE/PC meat and poultry products.
10 Although industry had contended that no outbreaks had been attributable to industrially produced meat and poultry products, FSIS cited in Revised Appendix B one
outbreak associated with C. perfringens from commercially produced RTE turkey loaf
product in 2000. The agency also took the opportunity to clarify a number of compliance criteria for heat-treated, not fully cooked products. FSIS acknowledged that
food safety concepts associated with RTE products may also apply to heat-treated
not-ready-to-eat (NRTE) products, such as ready-to-cook bacon.
The revised document includes recommendations previously provided in
Appendix B, FSIS Directive 7110.3, and examples of scientific evidence for establishments
to support a safe production process. Several options for cooling meat and poultry
products were provided, including requesting a waiver from regulatory performance
standards to allow up to a 2-log multiplication of C. perfringens within a product,
provided there’s no growth of C. botulinum, if the establishment collects data from
raw materials that demonstrate a relatively low level.
FSIS provided four recommendations for cooling now that limit growth of C.
perfringens to be less than 1 log with no growth for C. botulinum (Table 2).
In an attempt to allay some of the industry concerns about achieving Option 2,
FSIS published some recommendations for establishments that cannot meet the
11 Recommendations included pre-chilling the cooler before
loading product; increasing airflow (e.g., adding a fan) to speed cooling; and reducing the amount of product in each batch or lot placed in the cooler at one time to
reduce the total heat load to be removed. Additional answers to public comments
were provided pertaining to additional cooling options for establishments to use
based on modeling.
12 The agency also published additional information and guidance pertaining to the use of Option 3 for stabilization of products containing natural sources of nitrite and ascorbate.
FSIS outlines corrective actions for an establishment to consider when a cooling
deviation occurs, including pathogen modeling. Growth of more than 1 log C. perfringens (or 2-log growth) and greater than a 0.30-log increase of C. botulinum would
mean that product should be destroyed. The agency also recommended that processors assess B. cereus growth only if C. perfringens growth is estimated greater than
3 log. To aid product disposition determinations, product testing for C. perfringens
should follow n = 10, c = 2, m = 100, and M = 500. Due to the work of Mohr and
15 the compliance guideline clarifies that ComBase’s Perfringens Predictor
and the Smith-Schaffner models are most accurate for use in predicting growth of C.
perfringens in meat systems. If evaluating existing or conducting new validation stud-
ies, the recommendations in the FSIS
Compliance Guideline: HACCP Systems
Validation should be consulted.
types of scientific data that can be used
for validation include in-plant data,
modeling, challenge studies, and other
regulatory/public health agency reports
(e.g., Food Code, Canadian Food Inspection Agency, European Food Safety
Besides the industry concerns about
Appendix B previously mentioned, there
are additional concerns that the guideline contains general information that
could be misleading. For instance, the
guidance document cites from the U.S.
Food and Drug Administration, “The
minimum inhibitory salt concentration
for C. perfringens is 7%, and 10% for C.
botulinum.” However, these limits are in
growth media incubated at ideal temperatures. It’s been reported that 3 percent
salt completely inhibits C. perfringens in
beef and ham during extended cooling
for 21 hours.
17 Another term used is in
reference to the use of peer-reviewed
publications as scientific support for
cooling. The guideline states that in order to use such scientific support as validation, processors must ensure that their
cooling data “matches” that of the scientific support; however, there is no guidance or definition as to what constitutes
a suitable match. Another such phrase
concerning scientific references is that
“if establishment does not follow all
parts,” then the scientific reference may
not be applicable. The term “all” could
be misconstrued such that no scientific
reference would be suitable and that
every process would need to be validated by conducting a laboratory-scale or
pilot-scale study or in-plant validation
with surrogates. This would be unduly
cumbersome and costly to industry,
and small and very small establishments
usually lack the resources to perform
such work. The guidance mentions that
“critical operating parameters” need to
“FSIS has provided much more detail than in previous versions of
compliance guidelines for appendices A and B.”