Getting started

Where to start, and who to call first

Updated October 2026

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One: measure the finished equilibrium pH and the water activity Two: decide whether it has to be shelf stable Three: if shelf stable, call a competent processing authority Four: register, within ten days of first engaging Five: then the equipment The jar comes last and it is the easy part And preventive controls apply alongside all of it The order here is the opposite of every other property References

The first call is a competent processing authority, not a jar supplier.

One: measure the finished equilibrium pH and the water activity

Both, because the low-acid definition requires both to be over. Equilibrium pH means after the product has settled, not the pH of one component, and water activity needs an instrument rather than an estimate.

Two: decide whether it has to be shelf stable

Because that single decision is what brings part 113. A refrigerated or frozen product is not shelf stable and is therefore outside the thermally processed low-acid canned food regime entirely.

Three: if shelf stable, call a competent processing authority

The scheduled process has to be at least equivalent to one established by such an authority. That is a person with specific expertise, and the process they establish is the thing you then have to be able to deliver.

Four: register, within ten days of first engaging

On Form FDA 2541, with the name, principal place of business, the location of each establishment, the processing method in terms of the type of processing equipment employed, and a list of the low-acid foods processed in each.

Five: then the equipment

Part 113 sets requirements for thermal processing systems, including instrumentation, venting, temperature and pressure records and operator supervision, per retort type. A boiling water bath is not a retort and cannot reach these temperatures.

The jar comes last and it is the easy part

18 glass containers from 266 to 946 mL, all rated to a 300 F maximum fill temperature, with 171 closures of which 11 carry a pasteurization liner. That is a narrow and appropriate shelf.

And preventive controls apply alongside all of it

The current good manufacturing practice and risk-based preventive controls rules for human food sit under everything here, independent of which route you take.

The order here is the opposite of every other property

Everywhere else in this library you choose a container and then satisfy the rules. Here the filed process chooses the container, so shopping a shelf first is not just premature, it is the wrong sequence.

References

21 CFR 113.3, the definitions for thermally processed low-acid foods packaged in hermetically sealed containers. Paragraph (j) defines a hermetically sealed container as one designed and intended to be secure against the entry of microorganisms so as to maintain commercial sterility; (n) defines low-acid foods as those with a finished equilibrium pH greater than 4.6 and a water activity greater than 0.85, excluding tomatoes and tomato products below pH 4.7; (r) requires a scheduled process at least equivalent to one established by a competent processing authority. law.cornell.edu

21 CFR 108.35, Thermal processing of low-acid foods packaged in hermetically sealed containers. Paragraph (a) records that the harmful nature of such foods cannot be adequately determined after they have entered interstate commerce; (c)(1) requires a commercial processor to register with FDA on Form FDA 2541 not later than 10 days after first engaging in such processing, giving the establishment locations, the processing method in terms of equipment employed, and a list of the low-acid foods processed. law.cornell.edu

21 CFR part 113 generally, which sets the equipment and procedural requirements for thermal processing systems, including instrumentation, venting, temperature and pressure records and operator supervision for each type of retort. law.cornell.edu

21 CFR part 117, the current good manufacturing practice, hazard analysis and risk-based preventive controls regulations for human food, which apply alongside the thermal processing rules. law.cornell.edu

Written from federal regulation, not from a production kitchen. Nothing here is a scheduled process, and nothing here is a substitute for a competent processing authority. If you are considering a shelf-stable low-acid product, the first call is to a process authority rather than to a packaging supplier.