Catholic with a small c
Solution 1:
After a service, I asked a priest about the creed which reads, "one holy, catholic church" and said I thought I was attending an Anglican church.
He replied, "'Catholic' with a small c."
That was 20 years ago, so it would be understood in religious settings at the very least.
Solution 2:
I don't think it would be universally understood, chiefly because most English speakers don't realize there is a meaning to "catholic" other than "the Christian church that recognizes the Pope in Rome as its spiritual head".
That wouldn't make it a useless thing to say though. For instance my (non Catholic) church occasionally has us recite the Apostle's Creed, which contains the line:
I believe in the Holy Spirit, the holy catholic Church, the communion of saints, ...
This can cause a lot of confusion. I had a visiting Catholic friend ask me about it, and I've even seen some hymnals take the step of adding the unpronounced parenthetical "(universal)" after the word "catholic".
If you are looking for a good replacement word, I'd go with those protestant churches and use "universal".
Solution 3:
The collocation "catholic tastes" is certainly not obsolete. A quick look at books.google.com/ngram for recent uses (since 1982) of "catholic tastes" provides plenty of examples ranging from things like Shostakovich's "catholic taste in music “from Bach to Offenbach,” in gypsy music, street songs, and the music hall, were well established. Jazzderived rhythms, textures, and instrumental color had been assimilated into much of his music" to the Northern Hemisphere Minke whale's "catholic tastes" as opposed to its cousins in the Southern Hemisphere: "in the Northern Hemisphere, it has more catholic tastes and much fish is eaten."
Solution 4:
I'd understand it right away (but I cannot claim to be representative of what people would "generally" understand).
As an alternative,
- I eat anything
- I'll try anything [once]!
- I'm omnivorous
- I'm easy to please
- I'd like what you're having
- I'm a flexitarian <-- a new favourite
It wouldn't occur to me to describe a taste in food as "catholic", though:
- Because it has a religious tone, which because of Matthew 15:11 doesn't sound appropriate to me
- Because I think of it as "accepting" (of other people) ... I accept them, I'm not going to eat them!
https://www.google.com/search?q=catholic+etymology suggests that a good synonym of "catholic" is "universal".