5.3 Labeling & Package Integrity

Load and Lot Labeling for Traceability

Labeling is what makes a sterile item traceable. Per AAMI ST79 lot-control practice, every package leaving the sterilizer is labeled so the department can identify exactly what was in each load and recall it if a process failure is discovered. A complete label records the sterilizer identification, the cycle or load number, the date of sterilization, and often the operator initials. Many departments add content identification — the set name or a count-sheet reference — so staff can pick the right tray without opening it.

This information drives two daily realities. First, stock rotation: older packages are placed in front and behind newer ones so they are used first (first-in, first-out, or FIFO). Second, recall: if a biological indicator later fails or an instrument issue surfaces, the load number identifies every package processed in that cycle and where each was distributed, so they can be retrieved before patient use. Without complete labeling, a single failed biological indicator could force a facility to recall far more inventory than necessary — labeling narrows the recall to exactly the affected load.

Expiration Dating vs. Event-Related Sterility

There are two ways to express how long a package stays sterile:

• Time-related (expiration) dating — sterility is assumed to lapse on a fixed calendar date. This is required only when a packaged product or material itself carries a true expiration (for example, certain pouch materials or a manufactured sterile product). The package is removed from use when the printed date passes, regardless of condition.
• Event-related sterility (ERS) — a package is considered sterile until a specific event compromises it, not until an arbitrary date. Events that breach sterility include a tear, hole, wet pack, broken seal, dropped package, compression, or storage in a way that exposed it to contamination. ERS is the predominant model for in-house sterilized instrument sets because, kept intact and dry, a barrier system does not lose sterility simply because time passed.

A common exam trap: under ERS, a 6-month-old wrapped tray that is dry, sealed, and undamaged is still sterile, while a freshly processed tray with a torn wrap is not. Condition, not the calendar, governs. ERS also depends on a controlled storage environment — closed cabinets, controlled traffic, and protection from moisture and dust — because ERS only works if the events that would compromise a package are actually prevented and detected.

Chemical Indicator Placement

Chemical indicators (CIs) verify that the package met conditions for sterilization, and where they go is tested heavily.

Key rules: an external indicator alone never confirms sterility — it only confirms the package was exposed to a process. An internal CI is placed where the sterilant has the hardest time reaching, because if conditions were met there, they were met throughout. Peel pouches carry a printed external indicator on the film; an internal CI is added when required by policy or when the item is complex. The internal indicator is checked at the point of use, after opening, before the instruments touch the field.

Note the distinction the exam draws between a CI (verifies physical conditions) and a biological indicator (BI), which contains live spores and is the only monitor that proves microbial kill — a CI passing does not substitute for a BI.

Integrity Inspection Before Use

The last line of defense is the person opening the package at the point of use. Before a package is presented to the sterile field, inspect it for:

1. Intact barrier — no holes, tears, punctures, or abrasions in the wrap, pouch, or container; no broken container filter or bent retention plate.
2. Dryness — no moisture, water spots, or stains inside or out. A wet pack is considered contaminated.
3. Secure seals — pouch heat seals continuous and unbroken; wrap closures and tape intact; container latches and filters seated.
4. Acceptable external indicator — the process indicator shows the expected color change; no change means the package may not have been processed.
5. Legible label and correct contents — load information present and the package is the item needed.

Any failed criterion means the package is not used — it is returned for reprocessing, not patched or wiped. Crucially, a wet pack is contaminated even if the external indicator changed color, because moisture provides a wicking path for microorganisms (strike-through) from the unsterile outer surface to the contents. Labeling is applied to the indicator tape, the plastic side of a pouch, or a dedicated label; staff never write directly on the porous wrap or pouch paper with solvent-based or bleeding ink that can wick through and contaminate the sterile contents.