Pick the hazard and what happens to the food after sampling to get the ICMSF Case and its plan (n, c, m, M), then enter the results of the sample units to get the lot decision.
The ICMSF sampling plans decide whether a food lot is acceptable from microbiological tests on a small number of sample units. The plan gets stricter as the hazard of the organism grows, and as the handling expected after sampling makes it more likely to grow. You choose the hazard and what happens to the food afterwards; the tool gives the plan, then decides the lot from your results, with the operating characteristic (OC) curve and, for Pro, the risk at each mean concentration.
You set the limits m and M yourself from your national or customer standard; the tool does not supply them.
Plans follow the ICMSF Cases, checked against the published table, with hazard categories and example organisms from the ICMSF Cases concept. The risk curve uses the model of the FAO/WHO sampling tool. The tool supports, but does not replace, your national or customer standard and the judgement of a food safety professional.
The data behind “Try an example”: an indicator organism counted in CFU/g, no change in conditions, m = 100 and M = 1000.
| Result | Value |
|---|---|
| Plan | Case 5: 3-class, n 5, c 2 |
| Results (CFU/g) | 40 · 250 · 90 · 600 · 1500 |
| Units | 2 acceptable · 2 marginal · 1 above M |
| Decision | Lot rejected |
The two marginal units are within the plan’s allowance, but the lot is rejected because one unit (1500) is above M.