Process
Air drying
Water leaves the product until its water activity is low enough that nothing grows.
Published parameters
| Parameter | Value | Source |
|---|---|---|
| Water activity, stored in air | 0.85 or below | FSIS-GD-2014-0010 |
| Water activity, vacuum packed | 0.91 or below | FSIS-GD-2014-0010 |
| Moisture protein ratio, salami | 1.9:1 or less | FSIS-GD-2023-0002, citing 9 CFR 317.8 |
| Drying room days, Trichinella | 14 days at 1 inch to 50 days at 6 inches of casing diameter | FSIS-GD-2016-0002, Table 3 |
What the step is for
Produces shelf stability. Produces very little lethality.
Drying is the step that does the least of what people think it does. It makes a product shelf stable by taking water away from Staphylococcus aureus, which is the organism that can still grow when the others have stopped. It does not reliably kill Salmonella, which tolerates drying.
Weight loss is a proxy for water activity and a poor one, because fat carries almost no water. Two pieces at the same percentage loss can be at quite different water activities if their fat contents differ. The measurement that matters is the water activity itself.
The one place where drying time is published as a parameter is Trichinella control, where FSIS gives a table of drying room days by casing diameter and a schedule of adjustments for a warm hold beforehand and for reduced salt.
Hazards this step bears on
Arithmetic for this step
Regulatory citations are to the Electronic Code of Federal Regulations, Title 9, as in force on 1 January 2026. FSIS guideline citations give the guideline identifier; the documents are listed with their URLs on methodology.