Bjerrum, who collected the Sustainable City Awards 'Green Gong' prize from celebrity chef Raymond Blanc in March, said since she jointly founded the company with chef Jeremy Rose there had been big strides in sustainable practices in restaurants. However she said there was still more to do and perceptions of cost needed to be tackled.
"I think I have seen a huge shift in attitudes over the last five years. What is important is to make people understand that being sustainable can be very affordable. People have this perception that if you want to be more sustainable it is going to be costly."
Feng Sushi currently operates seven sites across London and continues to put sourcing of fresh and seasonal fish as a high priority as it prepares to open restaurant number eight in West Hampstead.
None of the sites sell blue fin tuna and instead use yellow fin tuna - the only ingredient that travels by air to reach the restaurants. Feng Sushi's menu changes every three months and its suppliers are generally as local as possible and must be environmentally-aware. Even the delivery side of the business is sustainable with bio-degradable boxes of food transported by vehicles powered with bio-diesel from cooking oil.
However Bjerrum warned restaurants who were not at this stage not to try and make the change overnight but start with the biggest and most affordable solutions.
"There is still a lot more to do but I think people take it much more seriously and people have stopped seeing it as just a buzzword; it is insurance for your business. Future supply issues and global issues are real and they are here and more and more people are taking them seriously."
It is now more than 18 months since serial entrepreneur Luke Johnson announced he had taken a 92 per cent stake in the business and Bjerrum admitted Feng Sushi might not have been able to make the next step without that sort of investment. "It gives you a lot of security. I had a very good relationship with the previous shareholders but they didn't have the same kind of experience as Luke has in running restaurants."
As well as making the business healthy, Johnson has been heavily involved with the online marketing, social media and customer feedback aspects of the operation as well as putting greater emphasis on the eating in offer.
The next opening in West Hampstead will be the template for future development with separate delivery/takeaway and dining in areas to avoid disturbance and more focus on comfort for the eat-in customers to increase dwell time.
Despite the slight change of focus Bjerrum said the original concept of bringing takeaway and eating in together would remain. "In retrospect I often think 'why on earth did we do that' but we have done it since day one and we made it work. I wouldn't advise against it but I think for some eat-in restaurants it is a real challenge to start up a delivery service because the logistics are quite tricky."
Future growth in terms of openings for the business has been delayed slightly with lengthy lease negotiations on the West Hampstead site but Bjerrum said they were looking for new sites but were not making targets.
"We are doing one, making sure that is up and running and then doing another one. We are not going to go for mass rollout mainly because it is a very detailed product so you want to make sure you have got everyone trained and fully aware of what they need to do before we open up another one," she said.
The business, Bjerrum concluded, would remain focused on London and areas such as Hackney, Clapham, Chiswick and Islington where Feng Sushi could develop a 'neighbourhood' customer base that would use the business for all three areas - eating in, takeaway and delivery.