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.
6.2.1. 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).
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).