Food microbiology laboratory: selective repeat testing, an out-of-calibration balance and an action plan that only corrects
During a scheduled assessment of a food microbiology laboratory, the assessor observes an analyst repeating a total viable count on the same sample three times and entering only the lowest result in the laboratory information system. The analyst says this is normal practice when a count looks high and that the supervisor knows. In the preparation room the analytical balance carries an in-house sticker reading next due 2025, but the calibration certificate in the equipment file expired five months earlier; the balance is used to weigh portions between 0.1 g and 1 g for the enrichment stage. No impact assessment has been performed. Two weeks after the closing meeting the laboratory submits an action plan: retrain the analyst, purchase a new balance, add a note to the standard operating procedure that repeat testing is not permitted, and reissue the three affected reports. There is no root cause analysis, no review of other benches, no customer notification and no check of results reported during the five months.
1. Formulate the nonconformities and classify them, explaining the reasoning behind each grade.
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Two findings, kept separate so each is testable and each can be corrected independently.
Finding one - selective repeat testing. Wording should be factual: on a stated date, the same sample was tested three times for total viable count and only the lowest count was recorded; the analyst described this as routine; the supervisor was aware. The breached requirement is 7.5, because technical records must contain original observations, data and calculations and enough information to permit re-testing, and the repeat results were never recorded. 7.10 is also engaged because nonconforming work was not identified and evaluated. Grade: major. Reasoning - the practice directly affects the validity of reported results, it is accepted routine rather than an isolated slip, and it defeats the purpose of the management system.
Finding two - balance used with calibration expired five months, with an in-house sticker contradicting the equipment record. Breaches 6.4 (calibration programme, status identification, action on out-of-tolerance equipment) and 7.5 (equipment records). Grade depends on impact: the balance weighs 0.1 g to 1 g portions that drive enrichment, so error propagates into the result, and the laboratory has performed no impact assessment. That justifies major. It could be minor only if the as-found calibration shows deviation within the tolerance relevant to those weighings and the failure is purely administrative - and the assessor cannot assume that, because the laboratory has not demonstrated it.
Avoid inflating the count: the supervisor's awareness and the absence of any detection mechanism belong inside these two findings, supported by 8.5 and 8.7, not as separate nonconformities.
2. Evaluate the action plan against 8.7 and 7.10 and decide whether to accept it, require follow-up, or recommend restriction. What is missing and why does it matter?
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Most of what was submitted is correction, not corrective action. Retraining, buying a balance, adding a procedural note and reissuing three reports address the symptoms. 8.7 requires action to eliminate the cause, based on analysis of the cause, proportionate to the effect of the nonconformity, with verification of effectiveness and records of what was done.
Missing, in order of importance:
Cause analysis. Why did an accepted practice develop? Turnaround pressure, unclear acceptance criteria for counts, supervisory tolerance, absence of any review of raw data before release? Retraining one analyst cannot fix a practice the supervisor endorsed.
Extent. Who else repeats tests, in which methods, over what period? The laboratory must review other analysts, other benches and records over a defined period, and state the result even if it finds nothing.
Impact on previously reported results, under 7.10. Where results may be invalid, the laboratory must evaluate significance, notify affected customers in writing, and issue amended reports clearly identified as amendments. Notifying nobody while reissuing three reports is arbitrary.
The balance's as-found calibration and the effect of every weighing during the five months, plus which methods are sensitive to that tolerance.
An effectiveness check with a date and an owner.
Decision: do not accept. Return the plan with a requirement for cause analysis, extent and impact, and state that the major nonconformities remain open. For a data-integrity finding, a documentary follow-up is weak evidence of cultural change; an on-site follow-up covering the microbiology bench and the historical data review is justified. Whether to suspend or restrict the affected scope is a decision for the accreditation decision-maker; the lead assessor recommends on the basis of the evidence.
3. What should the lead assessor recommend to the accreditation decision-maker, and what should the laboratory do about results already reported?
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The recommendation should be conditional and explicit: the accreditation decision cannot be taken until both major nonconformities are closed and the effectiveness of the corrective action is verified, with a follow-up visit because the issue is data integrity rather than documentation. A paper review cannot show that an accepted practice has stopped.
On results already reported, the laboratory must apply 7.10: evaluate the significance of the nonconforming work, including its impact on previous results, and take action that may include notification of the customer, recall of reports or issuance of amended documents. If the laboratory's own procedure and the sector's requirements demand notification of the regulator or of the customer's own accreditation stakeholders, that follows from those requirements; the assessor should ask to see the laboratory's procedure and how it was applied, rather than invent a rule.
The report must record the sequence honestly: what was observed, what the laboratory first proposed (an inadequate plan), what was subsequently required and what final state was verified. That record is what the decision-maker relies on and what protects the body if the laboratory disputes the outcome later. In the closing meeting the lead assessor should avoid any prediction of the decision, and should explain that the recommendation is one input among several.