The National Center for Home Food Preservation
Guide and Literature Review Series:
Smoking and Curing

 
 

Curing and Smoking Meats for Home Food Preservation
Literature Review and Critical Preservation Points


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6. Critical Preservation Points

These guidelines have been created by the NCHFP using the 2001 Food Code, which are recommendations created by the United States Public Health Service, Food and Drug Administration (PHS/FDA 2001), and other published science-based recommendations as referenced. The guidelines have been reviewed by the National Center for Home Food Preservation’s Advisory Board and external experts. Adhering to these guidelines will minimize the risk of exposure to food poisoning organisms. 

6.1. General Guidelines

6.1.1. Sanitation

All equipment, work surfaces, and utensils should be cleaned and sanitized before and after use (PHS/FDA 2001). An example of a sanitizing solution for home use is 1 tablespoon of chlorine bleach in a gallon of warm water (Marchello and Garden-Robinson 1998). Cross contamination between raw and/or dirty surfaces with clean or cooked food products should be of prime concern.

6.1.2. Storage/Refrigeration

During storage or refrigeration, raw products must be separated from cooked products. Never store raw products above or in contact with cooked products (PHS/FDA 2001). If necessary, place raw products in pans or utensils approximately 1-2” deep to keep meat juices from contacting with other surfaces.

6.1.3. Temperature

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.

6.2. Curing Guidelines

6.2.1. Meats

Meat must be fresh prior to applying any preservation method. Curing should not be used to salvage meat that has excessive bacterial growth or spoilage (PHS/FDA 2001). Meat, especially game meat, does not need to be aged, since curing/smoking will act to tenderize it. If aging is desired, age all meats below 40°F. (Cutter 2000).

6.2.2. Salt.

Only food grade salt without additives, e.g., iodine, should be used. Using salt with impurities can produce less desirable results, especially with fish (Turner, no date). Thawing must be monitored and controlled to ensure thoroughness and to prevent temperature abuse. Improperly thawed meat could cause insufficient cure penetration. Temperature abuse can allow spoilage or growth of pathogens (PHS/FDA 2001).

6.2.3. Curing Compounds

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). Dry cure using 3.5 oz. nitrate per 100 lbs. meat maximum or wet cure at a maximum of 700 ppm nitrates (9 CFR Cpt 3. 318.7(c)(4), 381.147(d)(4)).

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). Dry cure using 1 oz. nitrite per 100 lbs. meat maximum. For sausages use ¼ oz. per 100 lbs. (Reynolds and Schuler 1982). A 120 ppm concentration is usually sufficient and is the maximum allowed in bacon (PHS/FDA 2001).

Nitrites are toxic if used in quantities higher than recommended; therefore caution should be used in their storage and use (PHS/FDA 2001). About 1 g or 14mg/kg body weight sodium nitrite is a lethal dose to an adult human (USDA FSIS 1997b). Mistakenly using sodium nitrite instead of NaCl in typical curing recipes can lead to a lethal dose of nitrite in the incorrectly cured product (Borchert and Cassens 1998). For this reason it is safer to purchase and use curing mixtures rather than pure nitrites (saltpeter).

6.2.4. Cure Penetration

Cure mixtures do not penetrate into frozen meats. Before curing, it is essential to thaw meats completely first in the refrigerator. Pieces must be prepared to uniform sizes to ensure uniform cure penetration. This is extremely critical for dry and immersion curing (PHS/FDA 2001). Use an approved recipe for determining the exact amount of curing formulation to be used for a specified weight of meat or meat mixture (PHS/FDA 2001). All surfaces of meat must be rotated and rubbed at intervals of sufficient frequency to ensure cure penetration when a dry curing method is used (PHS/FDA 2001). Immersion curing requires periodic mixing of the batch to facilitate uniform curing (PHS/FDA 2001). Curing should be carried out at a temperature between 35°F and 40°F. The lower temperature is set for the purpose of ensuring cure penetration and the upper temperature is set to limit microbial growth (PHS/FDA 2001). Curing solutions must be discarded unless they remain with the same batch of product during its entire curing process –because of the possibility of bacterial growth and cross-contamination, do not reuse brine (PHS/FDA 2001).

6.3. Smoking

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.

6.3.1. Smoke Cooking

Consumers should smoke cook foods to internal temperatures as listed by the USDA (USDA-FSIS 1999).

Table 6.1. Internal Temperatures for Smoke Cooking of Foods (USDA-FSIS 1999).
Product °F
Ground Meat & Meat Mixtures
Turkey, chicken 165
Veal, beef, lamb, pork 160
Fresh Beef
Medium Rare 145
Medium 160
Well Done 170
Fresh Veal
Medium Rare 145
Medium 160
Well Done 170
Fresh Lamb
Medium Rare 145
Medium 160
Well Done 170
Fresh Pork
Medium 160
Well Done 170
Poultry
Chicken, whole 180
Turkey, whole 180
Poultry breasts, roast 170
Poultry thighs, wings 180
Stuffing (cooked alone or in bird) 165
Duck & Goose 180
Ham
Fresh (raw) 160
Pre-cooked (to reheat) 140
Seafood
Fin Fish Cook until opaque and flakes easily with a fork.
Shrimp, lobster, crab Should turn red and flesh should become pearly opaque.
Scallops Should turn milky white or opaque and firm.
Clams, mussels, oysters Cook until shells open.

6.3.2. Cooling

Cool cooked products rapidly to below 40°F and keep refrigerated. Cooked fish products should generally be cooled from to 70°F or below within 2 hours and to 40°F or below within another 4 hours (US FDA 1998). Minimize handling of cooked products. Dry (unfermented) products may not be hot smoked until the curing and drying procedures are completed. Semi dry fermented sausage must be heated after fermentation to a time/temperature sufficient to control growth of pathogenic and spoilage organisms of concern.

6.4. Trichinella

Pork products must be treated to destroy Trichinella by (a) Heat: A minimum internal temperature of 130°F(30 min.), 132°F(15 min.), 134°F(6 min.), or 136°F(3 min.), (b) Freezing: 5°F(20 days), -10°F(10 days) or -20°F(6 days) for all pork in pieces not exceeding 6 cu. inches. Double the freezing times for larger pieces up to 27 inches of thickness or (c) some combination of curing, drying, and smoking can kill Trichinella, but these are process specific (9 CFR 318.10).

FSIS approved of the use of up to 50% KCl2 in place of NaCl for the destruction of trichinae (USDA FSIS 1995c). Wild game (bear, elk, etc.) must be treated to destroy Trichinella by heating to 170°F, since some strains of Trichinella are freeze resistant (CDC 1985).

6.5. Fish

Intentionally under-processed fish (e.g., green herring, or cold smoked fish) should be frozen first to 4°Ffor 7 days to kill parasites (PHS/FDA 2001) or to -10°Ffor at least 7 days (Price and Tom 1995). Because spores of C. botulinum are known to be present in the viscera of fish, any fish product that will be preserved using salt, drying, pickling, or fermentation must be eviscerated prior to processing. Without evisceration, toxin formation is possible during the process. Small fish, less than 5 inches (12.7 cm) in length, that are processed in a manner that prevents toxin formation, and that reach a water phase salt content of 10%, a water activity of below 0.85, or a pH of 4.6 or less are exempt from the evisceration requirement (US FDA 1998). For salted and hot smoked fish, use brine with a minimum salt concentration of 3.5% water phase salt (Hilderbrand 1999). It is not recommended to hot or cold-smoke fish that have not been brined (Schafer 1999).

6.6. Ham Recommendations

For country ham, dry salt cured ham, country cured shoulder ham, or dry-cured bacon, the internal salt content should be 4% when used with nitrates/nitrites or 10% without the use of nitrates/nitrites. Properly prepared dry cured hams are safe to store at room temperature (Reynolds et al., In Press, PHS/FDA 2001). Soak country cured hams in water in the refrigerator (40°F) to reduce salt levels prior to eating (PHS/FDA 2001). High humidity during curing and aging may lead to surface spoilage. Mold may grow on the surface and can be safely washed off.

6.7. Sausage

All recipes should call for final internal temperatures that will destroy trichinae. We do not recommend preparing homemade, non-fermented sausages that are not fully cooked. If you do prepare them, be sure the meat, especially pork, has been properly frozen to destroy trichinae and other parasites. Use a meat thermometer to help insure that meat is kept cold before cooking and that sausage is properly cooked. Cool the sausage quickly after cooking and keep in the refrigerator for short term storage or freezer for long term storage (Busboom 1996). Semi-dry cured sausages, such as summer sausage, should be heat treated to 145°F for 4 minutes to destroy E. coli that may have survived the curing and fermentation process (USDA FSIS 1995).

6.8. Storage Guidelines

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.

6.9. At Risk Consumers

You can protect your unborn child by not eating shark, swordfish, king mackerel, and tilefish that can contain high levels of methylmercury (U.S. F.D.A. 2001a). "At risk" consumers should avoid eating refrigerated smoked seafood, unless it is in a cooked dish. Refrigerated smoked seafood, such as salmon, trout, whitefish, cod, tuna, or mackerel, is most often in recipes for "Nova style, "lox, kippered, smoked or jerky seafood. These preparations are at risk for Listeria monocytogenes contamination (U.S. F.D.A. 2001b). At-risk consumers might want to avoid dry cured sausages because of the risk of E. coli O157:H7 (USDA FSIS 1995b). Consumers may want to avoid feeding cured products containing nitrates/nitrites to babies less than three months old because of implications in Sudden Infant Death Syndrome (SIDS) due to nitrate/nitrite poisoning (methemoglobinemia).



Document Use | Preface | Table of Contents | References