The workers wear sterile clothes, hats and masks. The air is specially filtered. Every possible precaution is taken to maintain a completely sterile environment. So what might have happened one day last week at ITH Pharma Ltd that could have led to the death of one baby and blood poisoning for 17 others, now that three more cases have been confirmed this afternoon.
That is what inspectors from the Medicines and Healthcare Products Regulatory Agency, the MHRA, are currently trying to work out.
Liquid for parenteral nutrition is made to order for a specific baby's needs. Various ingredients supplied in large bags need to be mixed together: aqueous solution, oil which has been derived from a natural source like coconut or olives, plus a liquid containing other nutrients like vitamins. Once the bespoke mixture is made it needs to be packaged in bags or syringes to be shipped to hospitals.
So there are several points in the process when contamination could occur. It could be the raw ingredients, and a source within the industry has suggested to me that is the most likely explanation. But equally, it could be a fault with machinery - a blocked air filter, for example, which led to contamination of the room where the ingredients were being mixed. And then there's the packaging the mixed liquids are packed into - was that sterile?
ITH Pharma's manufacturing plant in north London is licenced by the medicines regulator the MHRA and inspected every two years. To keep its licence ITH must conform to "Good Manufacturing Practices" or GMP. This will include doing regular tests on equipment and clothing and verifying ingredients are not out-of-date and properly sealed.
The identification of the likely source of the infections has been swift. Now the investigation into the exact cause needs to be just as swiftly concluded, so health officials can ensure it does not happen anywhere else again.