Dear Dave,
Yes, I initially had much the same thoughts as your z-value comments.
However I was rather taken aback (see below) after looking at thermal data from a few seemingly validated publications. Unfortunately I was unable to find much data on current products of interest.
I have no wish to be alarmist since B.cereus (the selected pathogen of concern) only produces toxin at elevated bacterial levels and the products in OP all presumably have adequately "low" aw levels (<0.8 acc. to bnue, [location unspecified]) and were derived from good quality ingredients.
(Epidemiologically the types of product mentioned in the OP certainly seem to have an excellent safety track record over many years)
I haven’t seen many detailed posts here on “spore” aspects so I thought a little background detail might be of interest -
B.cereus seemed (from literature sources) the most appropriate sporing target to compare data against due the type of foods under discussion.
After a little digging, I was surprised to meet this comment in a rather authoritative looking document (attachment pp1 below) –
Only heat treatments used for canning of low acid foods will ensure a complete destruction of spores of B. cereus.
Followed by –
Inactivation of spores of B. cereus can only be guaranteed by a heat process equivalent to that used for low acid canned foods (F0 =3). However, this control measure cannot be used in most foods without dramatically altering their quality.
Inhibition of growth of B. cereus can be achieved by reducing water activity, pH and/or temperature. Temperature below 10°C greatly slows multiplication and temperatures below 4°C prevent it. Rapid cooling of heat treated foods through the temperature range supporting growth will also minimise multiplication before storage. After cooking, cool through the temperature range 55°C to 10°C as quickly as possible; store below 10°C (ideally below 4°C). Rapid cooling can only be achieved if the portion size is relatively small.
B. cereus, mainly spores, can persist on the surface of some processing equipment, which may increase the contamination of processed food. Good hygienic practices, HACCP, GMP, and using equipment designed to allow efficient cleaning, could reduce the initial number of B. cereus in processed foods.
Other pathogenic Bacillus spp. have some features similar to B. cereus: they produce heat resistant spores and they must be present in high numbers in foods to cause diseases. Control measures presented above for B. cereus certainly contribute to control other pathogenic Bacillus spp. However, there is little information in the literature on other pathogenic Bacillus spp. No routine methods easily detect and enumerate other species of Bacillus that could be involved in foodborne poisoning and no methods distinguish pathogenic strains among these species. The temperature and pH ranges allowing growth of pathogenic Bacillus other than B. cereus are not known. Therefore control measure specific to other pathogenic Bacillus spp are not available.
The same document also has a fascinating compilation of D values (ie time to achieve decimal reduction, referenced to mostly 90-100degC) for a range of foods (Table5, see pg 23). The most obvious feature is the wide variation in values, eg 0.3 to 100 min. Basically a 6D requirement involves multiplying the (maximum?) quoted D values by 6 to get a minimum time in minutes for a perfect (ideal) rectangular T vs t profile.
Another paper (pp2) for rice, which does indeed have a well-known history for occasional problems due B.cereus, quoted D(95degC) values of 1.5 to 36.2 min.
A third, 2000, paper (pp3) looks at necessary controls for a range of familiar spore-formers and more or less agrees with B.cereus comments in previous documents.
pp1 - Bacillus cereus in foodstuffs, 2005.pdf 199.18KB
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pp2 - B.cereus, inactivation in rice 2007.pdf 265.93KB
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pp3 - control of bacterial spores, 2000.pdf 742.91KB
275 downloadsRgds / Charles.C
PS
(added later) @bnue, I forgot to note earlier that i was unable to open the last 2/3 FDA links you previously provided. Seem to be working today and i found them excellent in readability and scope (although the comment in one article that biscuits have a high aw seems rather odd). Pls note my added comments in post # 7. I repeat the 2 links here for convenience to other posters -
http://www.fda.gov/f...s/ucm094145.htmhttp://www.fda.gov/F...s/ucm094147.htm2 sections which seemed directly useful are -
3.4. Processing steps
The current definition of "potentially hazardous foods" considers the effect of processing in much the same way that it considers pH and aw: it divides foods into two categories. Low-acid canned foods in a hermetically-sealed container do not require temperature control for safety. This rigid definition fails to address less processed foods, in less robust packaging, which still would not require temperature control for safety. Consider a baked product, such as a pie, with a pH of 5.5 and aw of 0.96. Since this product is baked to an internal temperature >180 °F (82 °C) to set the product structure of the pie, it will not contain any viable vegetative pathogens. Any pathogenic spores that survive the baking process will be inhibited by the pH and aw values listed above (ICMSF 1996; see tables 2 and 5). If the product is cooled and packaged under conditions that do not allow recontamination with vegetative pathogens, the product is safe and stable at room temperature until consumed, or until quality considerations (that is, staling) make it unpalatable.
Scientifically sound criteria for determining whether foods require time/temperature control for safety should consider 1) processes that destroy vegetative cells but not spores (when product formulation is capable of inhibiting spore germination); 2) post-process handling and packaging conditions that prevent reintroduction of vegetative pathogens onto or into the product before packaging; and 3) the use of packaging materials that while they do not provide a hermetic seal, do prevent reintroduction of vegetative pathogens into the product.
(appreciate that baked "pie" not relevant this thread, was temperature note that attracted me

)
and -
5.4. Time/temperature control
Although baked and fried cereal-grain products (for example, cakes, breads, muffins, and biscuits) have a high aw, a number of reasons may justify their shelf-stability: they have a long history of safe storage at ambient temperature; processing temperatures and moisture reduction, especially on the surface, preclude the growth of pathogens; and they are often formulated to include ingredients that enhance product safety and stability so as to permit distribution without temperature control for limited periods of time. Ingredients that are used to enhance safety and stability include humectants to reduce aw (sugars and glycerine), preservatives (calcium propionate, potassium sorbate, sorbic acid), acids to reduce pH (vinegar, citric acid, phosphoric acid, malic acid, fumaric acid), spices with antimicrobial properties (cinnamon, nutmeg, garlic), and water-binding agents to control free water (gums, starches). The primary mode of spoilage of baked goods is mold growth, which is visible and alerts the consumer to avoid consumption, further reducing the risk of illness due to spoiled product. These characteristics plus their long history of safe storage at room temperature would allow these products to be stored at ambient temperature. Boiled or steamed cereal products, such as rice, require time/temperature control after preparation due to the increase in aw.
The articles are laudably frank in commenting that the precise reasons for good safety records are not always immediately evident.
i deduce that above extracts may have provided the stimulus for the original nomination of 180degF however this becomes problematic if not matched to yr routine data as you suggested earlier.
I enclose 2010 extract indicating that (with exception of 2-3 species not AFAIK relevant in present case) L.mono is the "winner" for thermal resistance amongst common (vegetative) pathogens at approx. 60degC although this does not automatically ensure a similar listing at temperatures around 175degF (ca.80degC). If you can find such data, it will demonstrate that pathogens of concern in vegetative states can be considered as (6D) "eliminated" assuming that the z value in my previous posted table for L.mono is still valid or not changed to a more "resistant" value.
The spore related aspects are, IMO, adequately (validatably) explained by the comments in yr FDA links as quoted above.
D values for various microbial pathogens approx 60degC.png 276.59KB
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pp4 - food safety in hospitality sector.pdf 2.27MB
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