As a result of Zwingrow's pursuit of achieving the highest possible quality of bell peppers, Zwingrow started in 1996 by establishing responsibilities, procedures, instructions, environmental care and facilities. Experience has shown that processes can be streamlined better and improvements can be implemented faster and better. This has resulted in an extensive quality assurance system.

Zwingrow supplies a large part of the production through Harvest House to one of the market leaders in the UK, Tesco. Tesco demands a safe and reliable product from its suppliers. In 2011, Zwingrow was awarded the Tesco Nurture certificate by meeting far-reaching requirements.

Following the example of the retailers from the UK, the retailers and their suppliers have also set up a quality assurance system for the rest of the European retailers. This system is called GlobalGap. By meeting the requirements of European supermarkets, Zwingrow has obtained the GlobalGap certificate.