Infusing

Herbs and garlic under oil

Updated October 2026

On this page6

Why oil makes it worse rather than better The oil is not the problem; the solid is It is invisible Which is why 21 CFR 114 reaches this product What this means if you want to sell one References

This is the one genuine hazard in the property and it is worth being blunt about. Garlic, herbs and vegetables are low-acid foods, and oil excludes oxygen. Together at room temperature they are the condition the organism needs.

Why oil makes it worse rather than better

People reach for oil because it feels preservative, and it is the opposite. Oil keeps air out, and the organism in question grows where there is no air. Extension guidance states it plainly: when the spores are surrounded by oil an oxygen-free environment is created that encourages their growth at room temperature.

The oil is not the problem; the solid is

A plain oil with nothing in it is not a botulism risk, because there is nothing in it to carry the spores or to support growth. The hazard arrives with the botanical, the garlic clove, the chili or the piece of vegetable, and it arrives whether the solid is still in the bottle or was strained out after sitting in it.

It is invisible

There is no reliable appearance, smell or taste that tells you an oil is affected. That is the whole reason this is handled by a control applied in advance rather than by inspection afterwards, and it is why a maker cannot reason from the fact that nobody has got ill yet.

Which is why 21 CFR 114 reaches this product

Part 114 exists to set out how foods are manufactured and packed so as to prevent conditions in which the organism can grow. A commercially produced infused oil carrying a low-acid ingredient is acidified for that reason, and that acidification is a process control rather than a flavoring decision.

What this means if you want to sell one

Treat it as a product with a process behind it. That means a documented method, a conversation with your state and with a process authority, and an expectation that this is not a cottage food product. Nothing on this page is a determination that any particular method is adequate.

References

21 CFR 114, Acidified Foods, which sets the requirements for manufacturing and packing foods so as to prevent conditions in which Clostridium botulinum can grow. law.cornell.edu

Penn State Extension. How to Safely Make Infused Oils, including the citric acid soak and the refrigerated holding times. extension.psu.edu

Oregon State University Extension Service. Herbs and vegetables in oil, SP 50-701. extension.oregonstate.edu

Written from federal regulation, voluntary USDA grade standards, FDA labeling policy and published extension guidance, not from a laboratory. The infused-oil pages describe a real botulism hazard and are a starting point for a conversation with your state department of agriculture and a process authority, not a determination that any method you use is safe.