9 CFR § 431.4 - Critical factors and the application of the process schedule.

---
identifier: "/us/cfr/t9/s431.4"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "9 CFR § 431.4 - Critical factors and the application of the process schedule."
title_number: 9
title_name: "Animals and Animal Products"
section_number: "431.4"
section_name: "Critical factors and the application of the process schedule."
chapter_name: "FOOD SAFETY AND INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE"
subchapter_number: "E"
subchapter_name: "REGULATORY REQUIREMENTS UNDER THE FEDERAL MEAT INSPECTION ACT, THE POULTRY PRODUCTS INSPECTION ACT, AND THE EGG PRODUCTS INSPECTION ACT"
part_number: "431"
part_name: "THERMALLY PROCESSED, COMMERCIALLY STERILE PRODUCTS"
positive_law: false
currency: "2026-04-05"
last_updated: "2026-04-05"
format_version: "1.1.0"
generator: "[email protected]"
authority: "7 U.S.C. 1633, 1901-1906; 21 U.S.C. 451-472, 601-695; 7 CFR 2.18, 2.53."
regulatory_source: "83 FR 25308, May 31, 2018, unless otherwise noted."
cfr_part: "431"
---


# 431.4 Critical factors and the application of the process schedule.

Critical factors specified in the process schedule must be measured, controlled, and recorded by the establishment to ensure that these factors remain within the limits used to establish the process schedule. Examples of factors that are often critical to process schedule adequacy may include:

(a) *General.* (1) Maximum fill-in weight or drained weight;

(2) Arrangement of pieces in the container;

(3) Container orientation during thermal processing;

(4) Product formulation;

(5) Particle size;

(6) Maximum thickness for flexible containers, and to some extent semirigid containers, during thermal processing;

(7) Maximum pH;

(8) Percent salt;

(9) Ingoing (or formulated) nitrite level (ppm);

(10) Maximum water activity; and

(11) Product consistency or viscosity.

(b) *Continuous rotary and batch agitating retorts.* (1) Minimum headspace; and

(2) Retort reel speed.

(c) *Hydrostatic retorts.* (1) Chain or conveyor speed.

(2) [Reserved]

(d) *Steam/air retorts.* (1) Steam/air ratio; and

(2) Heating medium flow rate.