Know-How Exchange : Strategy

Longevity isn't a marketing strategy. It simply says, "we're still around". Start by finding out why people have purchased from you instead of your competitors, and then spread that message. This may be best be done by an outside market researcher to ensure you're getting accurate information rather than by having staff make guesses.

Content marketing to me is sending out contact that is useful, desirable,etc. for the customer. Examples of contact marketing are newsletters, blogs, white papers, etc. Here is a description: https://en.wikipedia.org/wiki/Content_marketing

The link below talks about how John Deere created a magazine called Furrow which provides information of help to farmers:
https://contentmarketinginstitute.com/what-is-content-marketing/
The magazine was not an advertising piece for John Deere, but a document filled with information that would be useful for farmers.

So you have a tagline of being in business 15 years. That really isn't the basis for content marketing. A better basis would be a newsletter that provides information about milk recipes or health benefits or how best to maintain shelf life or the like.

What does 15 year of experience allow your company to do or know that 5 years doesn't? In other words- What benefit does that 15 years of experience provide to your customers? You should be able to find something. What big or little thing do your people do that could set you apart from the other companies?

Content Marketing is the use of different marketing channels (print, broadcast, digital, social media, etc.) to tell a story (content) - a unique story. Now, this story content can be in the form of video, audio, text, or characters and should be broadly displayed on any of the aforementioned channels. Your story content has got to be a compelling one about your business (what makes you better than your competitor? what's your process?, etc.). Great content is crucial for brand awareness and will ultimately drive sales in this competitive market. "15 years of experience" is not content at all - it's just a business fact. I would suggest video content on your company website - maybe video showing how your dairy product is made and how it is different from the others. In essence, a visual essay on your company. In your industry, the video component would really resonate with your audience.