Ewithe.
I don’t think you need to overwork this part of the customer complaints. Although I think a well done Root Cause Analysis can help you find and solve the problem of almost any issue, even those that you consider “intangible” , not every complain deserves or require a RCA.
My suggestion is that first, you should develop a procedure for “Filtering” complains that will require RCA. No every complain justifies a RCA. You can use a matrix that includes for instance Severity and Frequency. For those infrequent and no severe issues you can just make a quick investigation or report, I mean, If you sell ice cream, is very possible that at least one gets melted before reaching the customer.. but is this really critical? it is worth the time? ....anything could have happed in the distribution chain.
On the other hand, if you start getting many events of melted ice cream, then you have a problem that requires a full RCA.
Same for the foreign object. As per my experience with this, many customer “bite” foreign objects when eating a product, but the objects actually comes from other sources. For instance that are eating other food together and the object comes from that other food, or sometime even small pieces of their own teeth or even a grain of sand transfered from soiled hands feels like a huge glass when smashed between your teeth. That may be the reason why they never find or send the actual object. So we get to the same point, if you get one single severe event, such as actual foreign object that your customer can actually photograph or send you, that more likely came from your factory and requires a CAR. Or, if you have many compliant from people that “feel” something but cannot find it, that may represent an issue that requires a CAR as well, it may be as simple as you have hard ice particles in the soft ice cream that feels like “rocks” (then you have an issue with the process) or you may have cross contamination from very small particles, such as sand…
The important thing for SQF requirements is to have a clear process for determining when you are going to do a CAR or no, and have a documented procedure for defining this (e.g. More than 3 times in a week/or month, More than $ value of goods, critical for health or business….etc)
While customer complaint has an enormous value for Quality and Process Improvement, you cannot chase after every little complaint. Once I asked to get my coffee to be changed 3 times at Dunking Donuts because it tasted really bad… Just for realizing hours later that I was sick, and that was causing me to get a bitter taste on my food…. I hope Dunking Donuts didn’t start a CAR on my complain because after much time and money spent to get it solve, they would still scratching their heads….