§ 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.