Bacterial sampling on a production line

A cosmetic product manufacturer located in the north of the country was experiencing problems with bacterial contamination in the one of his product lines. The technical team has suspected that one of the product filling lines is not operating appropriately and may be the source of bacterial in the product. It has been decided that the whole product filling line will be taken offline and cleaned to remove any bacterial contamination.

To evaluate the presence of bacterial we have agreed that the samples will be collected from various components of the production line and individually tested before and after the clean.

The microbiological samples were collected using Sterilin Transport Swabs Amine W/O charcoal and transported to the laboratory under temperature controlled conditions. The microbiological samples were plated onto Tryptic Soy Agar (TSA) and cultured at 28-30C. Bacterial count was carried out after 3, 4 and 7 days culturing periods. The cultured bacteria were differentiated between Gram positive and Gram Negative bacteria. Alongside each microbiological sample a swab sample has been collected to be analysed on site for the presence of protein residue as an indicator of microbiological contamination. The sample results are expressed as number of RLU units.

The pre clean samples show a relatively low level of bacterial on the individual components. The bacterial levels on most samples ranged between 0 to 40CFU/Swabs, only 5 out of approximately 30 samples showed bacterial concentration between 100 and 600 CFU/swab. Following the deep chemical clean of every component of the system the product filling line was flushed with 80 degrees water for several hours. After the flush some of the systems components were dismantled and bacteria levels were measured. The concentration of bacterial after clean and after hot flush on the tested components paradoxically ranged between 200 and 2200 CFU/swab.

The affected system was then run for approximately 10 days after which the whole procedure was repeated. In this case the pre clean bacterial levels on 7 of the components exceeded 3000 CFU/swab. After hot flush for several hours the one of the components tested showed bacterial levels exceeding 3000CFU/swab.

After the evaluation of the results we have concluded that the production machine was getting contaminated by bacterial from an external source and further investigation is necessary to track this source down.

By Tomas Gabor

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