Chapter Three

The Stomacher®- My legacy by Dr Anthony Sharpe

At the Patents Dept in Unilever House, agent Tom Tribe wrote a very successful patent disclosure and no other company managed to market a competitive machine until the patents expired. I continued to invent and design products after leaving Unilever. One of these, (called the Pulsifier), inspired Seward to develop the Stomacher® 400 Circulator. Seward engineers, referring to mine and Adrian’s original published paper, looked at the basic physics we hypothesised to explain how Stomacher® does what it does. They focussed on the shearing forces that generate the washing action, which compliments the crushing action. It was found that by enhancing these forces (by circulating the sample and buffer inside the bag), they could prepare samples with less debris and that counts improved, especially if the contamination was surface bound.

In recent years Seward has advanced the technology further, doing away with the door and applying some other tricks from our original paper, such as using textured blending surfaces and other innovations (see the Stomacher® EVO 400). But the basic principle remains the same, 50 years on.

Now, as I have a chance to look back at my career, it’s amazing to reflect on the extraordinary success of mine and Adrian’s brainchild. Tens of thousands of Stomacher’s and their copies and clones, operating in every country and territory on the planet, keeping the food supply chain safe. It is quite a legacy and an extraordinary story.