esa compania garantiza los alimentos

garantia = secured, guaranteed

I would just use food safety.

"El Plan de garantía de calidad del salmón irlandés fue el primer plan de garantía de calidad alimentaria de toda Irlanda certificado con la norma EN45011"..... This led me to look at that Certification - it´s about food companies' compliance to quality standards. So the set-up can provide information to / back-up for its occupiers on those subjects. Or there might even be companies running these standards inspections. (Huge amounts of paperwork for very small companies to cope with, but in order to compete with the multinationals you have to do it.... but that´s another question!)

ie, they undertake/guarantee to supply food/feedstuffs and services.

I think it may be that sort of "guarantee", simply by a process of elimination!
Other than insurance companies, I've never heard of a company that can merely "guarantee" food and services without also being a provider of said food and services, ie, it guarantees/ensures/undertakes the supply of...