What goes wrong

A jar does not make it shelf stable

Updated October 2026

On this page8

How it happens Why the seal feels like the answer And the jar is what brings the regime Hot filling is not thermal processing Nor is a boiling water bath And the product will not tell you Which is why this page exists at all References

The most dangerous misunderstanding in this library: a good seal is not a process.

How it happens

A maker hot fills soup into a jar, the lid pops down as it cools, and the seal is genuine. The jar is sealed and the product is not commercially sterile, and those are different things.

Why the seal feels like the answer

Because for an acidified product it very nearly is: acid does the safety work and the seal keeps it that way. Carrying that intuition across to a low-acid food is the specific error.

And the jar is what brings the regime

A hermetically sealed container is one designed and intended to be secure against the entry of microorganisms. Sealing the jar successfully is what puts the product inside the definition rather than outside it.

Hot filling is not thermal processing

A hot fill raises the product temperature and can address vegetative organisms. It does not reach spores, and the commercial sterility definition is explicit about viable microorganisms including spores of public health significance.

Nor is a boiling water bath

Water boils at a temperature below what is needed for a low-acid food, which is why pressure is involved at all. A longer boil does not substitute for a higher temperature.

And the product will not tell you

The regulation says the harmful nature of such foods cannot be adequately determined after they have entered commerce. A jar that looks, smells and tastes correct carries no information about this hazard.

Which is why this page exists at all

We sell jars. A jar is the right container for a great many things and it is not a process for this one, and saying so is more useful than selling eighteen of them into a product that should not be made this way.

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

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.