The organization must determine and maintain “the knowledge necessary for the operation of its processes and to achieve conformity.” The organization is the one who determines what knowledge is necessary and I suggest you review the Organizational Knowledge Annex A.7 to ISO 9001:2015.
Also the ISO/IAF Auditing Practices Group Guidance on Organizational Knowledge makes reference to the following:
1) Knowledge is a resource needed for the organization to support the quality management system processes, quality activities, and to ensure conformity of products and services.
2) Organizational Knowledge is the specific knowledge of the organization, coming either from its collective experience or form the individual experience of its persons.
3) Organizational knowledge in the persons of the organization may be recorded in documented information, imbedded in the processes, products and services of the organization, etc. Examples include documented information regarding a process, product or service specifications, and work instructions.
4) Knowledge and knowledge management vary considerably according to an organization’s context, the sector it operates in, the competitiveness of its markets, etc.
5) Organizations should consider internal and external sources, such as
- Learning form failures, near miss situations and successes;
- Gathering knowledge from customers, suppliers and partners;
- Capturing knowledge that exists within the organization;
- Benchmarking against competitors;
- Sharing organizational knowledge with relevant interested parties
- Updating the necessary organizational knowledge based on the results of improvements
- Knowledge coming from conferences, attending to fairs, networking seminars, or other external events.
Remember your organization is the one who will determine what knowledge is necessary and not the 3rd party auditor. When you start to address auditors question on this your answer should (my recommendation) start with “based on the context of the organization…” this limits the scope of the question and informs the auditor that it is based on the organizational context determined in Section 4 of ISO 9001.