Can't Cut the Mustard?

Today I came upon the phrase (which I've heard many times), "Can't cut the mustard." Being in a nosey mood (hmm... nosey...), I had to at least Google the origins.

Dave D. Grisham at University of New Mexico posted on his Word Origins website:
Whatever the origins of 'can't cut the mustard', they are about as clear as mustard, the expression 'too old to cut the mustard' is always applied to to men
today and conveys the idea of sexual inability. ' Can't cut the mustard',
however, means not to be able to handle any job for any reason, not just because of old age. Preceeding the derivation of 'too old to cut the mustard' by about half a century, it derives from the expression 'to be the mustard'. "Mustard" was slang for the " genuine article" or " main attraction" at the time. Perhaps someone cutting up to show that he was 'the mustard', or the greatest, was said 'to cut the mustard' and the phrase was later meant to mean to be able to fill the bill or or do the important or main job. In any case, O. Henry first used the words in this sense in his
story "Heart of the West" (1907) when he wrote: " I looked around and found
a proposition that exactly cut the mustard". Today, 'can't cut the mustard' is usually 'can't cut it' or 'can't hack it'. A recent variant on 'too old
to cut the mustard' is 'if you can't cut the mustard, you can lick the jar'. -- QPB Encyclopedia of Word and Phrase Origins By Robert Hendrickson

Dave Wilton at Wordorigins.org summarizes the Oxford English Dictionary's entry:

This phrase is from a metaphor where the mustard is something that adds flavor or zest to life, something that is good. Something that cuts the mustard is very good.

The phrase dates at least 1898. From the Decator, Illinois Herald Despatch of 6 April of that year:

John J. Graves, tight but that ha cun’t cut the mustard.

Mustard has a long history of being used as a metaphor for something powerful or biting. First in a negative context, as in John Heywood’s A Dialogue Conteinyng the Nomber in Effect of All the Prouerbes in the Englishe Tongue (1546):

Where her woordes seemd hony,...Now are they mustard.

And somewhat later in a positive sense. From James Howell’s Lexicon Tetraglotton (1659):

As strong as Mustard.

The origin of the cut portion of the phrase is uncertain. It could be a reference to cutting a mustard seed, a very difficult task. Or it could be a conflation with a cut above, to cut the mustard is to be better than mustard.

The phrase is also rendered as to be the mustard and it’s very similar to keen as mustard.

Various explanations that it is a corruption of a military phrase to cut muster or that mustard is a difficult crop to harvest have no evidence to support them.

Now, I just need to find out about "cut the cheese"...