Thank you once again JJ. The info you provided is one of many articles researched trying to find if Clostridium botulinum was a concern when smoking or grilling foods.
Using what you have provided, I have gleaned some of what was felt to pertain to my original question as to the possible growth of Clostridium botulinum while smoking foods. I am still unable to find any reference connecting Clostridium botulinum and smoking foods.
My personal summary is, there is absolutely nothing to worry about concerning c botulinum while smoking or grilling foods. Of course proper handling, cooking, and storage procedures should be kept.
Amount of oxygen required to sustain fire and smoke
When the percentage of oxygen reaches 13–15%, the fire will begin to smolder. Ordinarily, a minimum concentration of 15 percent oxygen in the air is needed to support flaming combustion. However, smoldering combustion can take place in an atmosphere with as little as 3 percent oxygen.
http://hawsepipe.net/chiefhelp/Firefighting/Fundamentals_Of_Firefighting.htm
[h1]Curing and Smoking Meats for Home Food Preservation
Literature Review and Critical Preservation Points[/h1]
Document Use | Preface | Table of Contents | References
[h2]5. Food Safety of Cured and Smoked Meats[/h2][h4]5.1.1. Non-traditional foods and non-traditional processes[/h4]
Today, consumers demand foods that are minimally processed, as "natural" as possible, and yet are convenient to use. Complicating these factors is a consumer preference toward cured and smoked foods that are processed with lower salt, lower nitrate and higher moisture levels. These parameters have a tremendous impact on the safety of a given cured/smoked food or process. Preferences for low fat and low sugar have less impact on the safety, but these factors can change the traditional curing and smoking process. It will be difficult to completely eliminate the use of nitrite, as there is no known substitute for it as a curing agent for meat.
Clostridium botulinum requires a low oxygen atmosphere and therefore, vacuum packaging favors its growth (Andress 2001). In cured meats, careful attention must be paid to proper use of nitrates/nitrites that inhibit Clostridium botulinum prior to use of in-home vacuum packagers.
The majority (65%) of botulism cases are a result of inadequate home food processing or preservation (CDC 1998). Botulism results from ingestion of a toxin produced by the bacterium C. botulinum. This bacterium requires a moist, oxygen-free environment, low acidity (pH greater than 4.6) and temperatures in the danger zone (38-140°F) to grow and produce toxin.
Note: The above mentions oxygen free environment, not low oxygen.
C. botulinum forms heat resistant spores that can become dangerous if allowed to germinate, grow, and produce toxin. Sufficient heat can be used to inactivate the toxin (180°F for 4 min., Kendall 1999).
[h3]5.2. Food Poisoning Organisms[/h3]
Details on pathogenic organisms mentioned below can be found in the FDA Bad Bug Book (US FDA 1992).
[h4]5.2.1. Botulism[/h4]
The majority (65%) of botulism cases are a result of inadequate home food processing or preservation (CDC 1998). Botulism results from ingestion of a toxin produced by the bacterium C. botulinum. This bacterium requires a moist, oxygen-free environment, low acidity (pH greater than 4.6) and temperatures in the danger zone (38-140°F) to grow and produce toxin. C. botulinum forms heat resistant spores that can become dangerous if allowed to germinate, grow, and produce toxin. Sufficient heat can be used to inactivate the toxin (180°F for 4 min., Kendall 1999). C. botulinumthrives in moist foods that are low in salt (less than 10%), particularly when they are stored at temperatures above 38°F. These organisms will not grow in an aerobic environment, but other aerobic organisms in a closed system can rapidly convert an aerobic environment to an anaerobic environment by using the oxygen for their own growth, permitting growth of C. botulinum.
For more information, please refer to the following resources:
- Botulism in the United States, 1899 - 1996 (CDC 1998).
- Potential Hazards in Cold Smoked Fish: Clostridium botulinum type E. (US FDA 2001c).
- Botulism (Kendall 1999).
[h4]5.2.2. Clostridium perfringens[/h4]
Spores of some strains of Clostridium perfringens are so heat resistant that they survive boiling for four or more hours. Furthermore, cooking drives off oxygen, kills competitive organisms, and heat-shocks the spores, all of which promote germination to vegetative or growing cells. Once the spores have germinated, a warm, moist, protein-rich environment with little or no oxygen is necessary for growth. If such conditions exist (i.e., incorrectly holding meats at warm room temperature for smoking), sufficient numbers of vegetative cells may be produced to cause illness upon ingestion of the contaminated meat product.
[h3]5.3. Inhibition of Pathogens in Cured Meats[/h3]
Salt and nitrates or nitrites are the primary chemicals that are responsible for the inhibition of pathogen growth when curing meats. Adding to that, pH and temperature (below 40°F or above 140°F), these factors can act in concert to prohibit the growth of pathogens in these foods. Table 5.3. indicates some extreme parameters for growth of pathogens.
Table 5.3. Critical Parameters for growth of some Pathogens (Corlett Jr 1998).
| | | | |
|---|
Organism
|
min. pH
|
max. % salt
|
min. temp.
|
oxygen req.
|
|---|
Clostridium
|
4.7
|
10
|
38°F
|
AN[sup]2[/sup]
|
[sup]2[/sup]AN=anaerobic, requires the absence of oxygen;
| | | | |
[h3]5.5. Cured/Smoked Food Spoilage[/h3]
Not all microbial growth leads to food poisoning. Indeed, many organisms simply spoil cured and smoked foods making them unpalatable. Keep in mind that it is a general rule that if conditions exist to allow growth of spoilage organisms, these same conditions can allow for the growth of food poisoning organisms. Good judgment should prevail.
|
|
[h4]
6.1.3. Temperature[/h4]
The danger zone for microbial growth is 40-140°F (
USDA FSIS 1997b). Therefore, store, age, cure, or otherwise preserve meats in a refrigerator below 40°F. Cooking meats to an internal temperature of 160°F will destroy bacteria that can cause foodborne illness (
USDA FSIS 1997b). Any recipe that minimizes preservation time within the temperature danger zone followed by cooking to a safe internal temperature will minimize risks of food poisoning.
[h4]
6.2.3. Curing Compounds[/h4]
Purchase commercially prepared cure mixes and follow instructions carefully (
PHS/FDA 2001) or blend cure mixes carefully at home using an accurate scale.
Nitrate. Use cure mixtures that contain nitrate (e.g., Prague Powder 2, Insta-Cure 2) for dry-cured products that are not to be cooked, smoked, or refrigerated (
PHS/FDA 2001).
Nitrite. Use cure mixtures that contain nitrite (e.g., Prague Powder 1, Insta-Cure 1) for all meats that require cooking, smoking, or canning (
PHS/FDA 2001)
[h3]6.3. Smoking[/h3]
Verify that smokehouses operate as intended (heat, airflow, moisture). Appropriate calibrated thermometers should be used (for cooking temperature and meat internal temperature). Procedures for delivering the appropriate thermal treatment of cooked meats in conformance with the Food Code must be developed and used. Smoke itself, without proper cooking, is not an effective food preservative (
Hilderbrand 1999). Caution should be used when smoking meats at temperatures in the danger zone 40-140°F for prolonged periods of time. In such a case meats must have been salted or cured first.
[h3]6.8. Storage Guidelines[/h3]
Store Cured/Smoked Poultry up to two weeks in the refrigerator or up to one year in the freezer (
TAES Extension Poultry Scientists 1999). Store lightly cured fish 10-14 days in the refrigerator or 2-3 months in the freezer (
Luick 1998). Vacuum packaged meats, e.g., smoked fish, must be kept at 40°F, since the reduced oxygen atmosphere increases the risk of botulism poisoning (
Luick 1998). Modern fish curing/smoking recipes produce a highly perishable product that rarely keeps better than the raw fish.
