I clearly have no microbiological background, so ...
Dealing with the inactivation of C.botulinum type B per FDA Appendix 4, table A-4 below.
Our data logger in clam chowder had a couple of "blips" where the product temperature fell slightly below 194, and so I've got a span of 7 continuous minutes, then a minute under, then another 6, then a minute under, and then another 7.
My question - does the 10 minutes @ 194F need to be continuous, or can it cumulative? Also, any reference material stating one way or another would be most appreciated.
Table A-4 contains information on the destruction
of Clostridium botulinum (C. botulinum) type B
(the most heat- resistant form of non-proteolytic
C. botulinum). Lethal rate, as used in this table, is
the relative lethality of 1 minute at the designated
internal product temperature as compared with
the lethality of 1 minute at the reference product
internal temperature of 194°F (90°C) (i.e., for
temperatures less than 194°F (90°C), z = 12.6°F
(7.0°C); for temperatures above 194°F (90°C),
z = 18°F (10°C)). The times provided are the
length of time at the designated internal product
temperature necessary to deliver a 6D process
for C. botulinum. The values in the table are
generally conservative. However, these values
may not be suficient for the destruction of non
proteolytic C. botulinum in dungeness crabmeat
because of the potential protective effect of
lysozyme. You may be able to establish a
shorter process time for your food by conducting
scientiic thermal death time studies. Additionally,
lower degrees of destruction may be acceptable
in your food if supported by a scientiic study of
the normal innoculum in the food.