A trace request starts with the code on the jar. Everything after that depends on what you put in it.

By Jeremiah Utecht · Compliance · August 25, 2026

A buyer calls on a Thursday afternoon. They have a jar in front of them and they read you six digits off the bottom: 072225.

You know what that means. It was packed July 22, 2025. You packed on July 22, 2025, which was a Tuesday, and you ran the hot fill twice that day because the first run came up short.

So which run is in their hand? Which ginger lot went into it? Did that lot go anywhere else?

The code told you the date. It did not tell you the batch. And the difference between those two things is the difference between pulling one afternoon of product and pulling a month of it.

Most small producers get to a lot code by accident. Somebody needed to put something on a label, the date was right there, and it became the system. It works fine right up until the day somebody asks a question the code cannot answer.

Here is how to design one that can.

01A lot is a decision about how much you are willing to pull

Before the format, the definition. A lot is the group of product you would recall together, because you cannot prove they are different from each other.

If your lot is a calendar day, a problem in the second run recalls the first run too. If your lot is a production run, the problem stays inside that run. If your lot is a month, which happens more than you would think when a code carries only a month and year, one deviation takes the whole month with it.

Nobody sets out to define a broad lot. It happens because the code was designed to be easy to print, not to be narrow.

Narrow the lot and you narrow the recall.

The regulation covering FDA's Food Traceability List foods draws that line in a specific place. Under 21 CFR 1.1320, a new traceability lot code gets assigned when you initially pack a raw agricultural commodity, when you perform first land-based receiving of food from a fishing vessel, or when you transform a food. That is the whole list. If you take in ingredients and make something out of them, transformation is your trigger, and it is the moment your lot starts.

The same rule says you must not create a new code when you do other things with that food, shipping included. The code you assign is the code that follows the product out the door. That is what makes a forward trace possible on the other end.

02FDA tells you the code must be unique. It does not tell you what to put in it

This surprises people. The definition in 21 CFR 1.1310 is: "A descriptor, often alphanumeric, used to uniquely identify a traceability lot within the records of the traceability lot code source."

Unique. Within your records. That is the requirement. There is no mandated format, no required number of digits, no prescribed date convention.

Which means the burden lands somewhere less comfortable than a format spec: it lands on your records. A code is only as good as what it points to.

There is one corner of the food code where FDA does get specific, and it makes a useful model even if it does not apply to you. For low-acid foods in hermetically sealed containers, 21 CFR 113.60(c) requires a code permanently visible to the naked eye that identifies the establishment, the product, the year, the day, and the period packed. It also says the period designation should change at intervals not longer than one shift, roughly every four to five hours, at shift change, or by batch, so that a lot can be identified during distribution.

The reason FDA wants that period marked is so a lot can be found in the field. That logic holds whether or not you are canning anything.

03Put in enough to be useful, and not one character more

A workable scheme for a small producer has four parts. Date packed, six digits, YYMMDD: human readable, sorts correctly, and unambiguous between US and international order once your team knows the convention. A product identifier of two or three characters, not the full SKU, just enough to tell a habanero sauce from a green sauce on sight. The run within the day, one character, which is the piece almost everyone skips and the piece that keeps a bad afternoon from becoming a bad month. And nothing else.

250825-HAB-2  ·  packed August 25, habanero, second run

The temptation is to keep encoding. Supplier initials, tank number, operator, shift. Resist it. Every character you add is a character somebody has to hand write on a wet production floor, transcribe into a log, and read correctly off a jar eighteen months later over the phone. A twenty-character code is not more traceable than a ten-character code. It is just harder to say out loud.

The code does not need to contain the information. It needs to point to it.

Two more failure modes: codes that reset annually and collide with last year, and codes that are purely sequential with nothing behind them. A number that is unique but meaningless is fine if the record it opens is complete. It is worthless if it opens a binder.

04The record behind the code is the part that gets audited

This is where lot coding stops being a labeling question and becomes a records question.

The Bioterrorism Act recordkeeping rule at 21 CFR 1.337 requires records of food received to include the lot or code number or other identifier of the food, and then adds five words that do a lot of quiet work: "to the extent this information exists."

If your receiving log has a supplier and a date but no incoming lot number, that information does not exist. The trace stops at your back door. Not because you did anything wrong on the floor, but because nobody wrote down the number. That is the same gap that makes supplier lot tracking the first thing to fix.

A lot code earns its keep only if pulling it up returns, without anyone reconstructing anything from memory: every ingredient lot consumed, the CCP readings taken during the run, who ran it, the quantity produced, and every customer who received part of it.

In a spreadsheet, the lot code is a text column. Nothing enforces uniqueness. Nothing links the code forward to the shipments that carried it. Nothing prevents somebody from typing 072225 in two different rows six weeks apart. The column looks like traceability and behaves like a label.

05Test it before somebody else does

Pick a jar off your own shelf. Read the code. Start a timer.

Name the ingredient lots, the CCP readings, the operator, the yield, and the customers. If that takes you more than half an hour, your records are the problem and the code just made it visible.

The clock matters because it is written down. Under 21 CFR 1.1455, records required by the Food Traceability Rule must be made available to an authorized FDA representative within 24 hours of request, or within some other reasonable time FDA has agreed to. When FDA requests traceability information in a food safety situation, it has to come as an electronic sortable spreadsheet, with the context needed to read it, unless you meet one of the small business exemptions in that section.

That rule's compliance date moved to July 20, 2028, extended from January 20, 2026. That is time to prepare, not a reason to wait. The lot code you assign next Tuesday is the one you will be tracing backward from in 2028, and codes are far easier to design than to redesign. If you have not started, the traceability plan comes first.

Your auditor is not scheduling an appointment. Neither is your buyer.