USDA PLant # 2435 is-
HILLSHIRE FARM & KAHN'S
N3620 COUNTY HIGHWAY D
NEW LONDON, WI 54961
Pepperoni, and other "dry" sausages, have a shelf-life determined by something called Moisture-Protein Ratio (MPR).
Lack of moisture and acidity levels inhibit pathogenic growth, thereby giving an extended shelf-life. Quality doesn't come into play.
From the USDA Labeling Policy:
SAUSAGE - SHELF STABLE:
Dry sausage must have a Moisture Protein Ratio (MPR) of 1.9:1 or
less, unless an MPR is cited under MOISTURE PROTEIN RATIO.
Non-refrigerated, semi-dry, shelf-stable sausage must have an MPR
of 3.1:1 or less and a pH of 5.0 or less, unless commercially
sterilized or unless an MPR is cited under MOISTURE PROTEIN
RATIO. Alternately, non-refrigerated, semi-dry, shelf-stable
sausages are those that:
1. are fermented to a pH of 4.5 or lower (or pH may be as high as
4.6 if combined with product water activity no higher than 0.91),
2. are in an intact form or, if sliced, are vacuum packed,
3. have internal brine concentration no less than 5%,
4. are cured with nitrite or nitrate, and
5. are smoked with wood.