Is butter with brown spots okay to use?

My guess is it's a handling issue. Perhaps condensation penetrating the paper wrapper? Trapped moisture and the lack of oxygen would create ideal conditions for mold, same reason tight wrapping is bad for cheese.

"Wet surfaces, wet wrappings, or high humidity are essential to mold growth in butter. Mold will not grow upon the surface of a piece of butter exposed to humidities of 70 per cent or lower."

So, where is the moisture coming from? My butter compartment? I have only found this in a fresh stick of butter as I am opening it.

I want my Tillamook Butter back. :-\

I think I will have to simply avoid Lucerne and pay the extra buck a pound if it isn't on sale. ChefOno makes a serious and valid point.

I have had these dark spots appear on my unsalted Lucerne butter more than once. It has happened with Butter I bought in Oregon and her in New Mexico. Lucerne every time. At first I tossed it, but now I remove those areas and use it. As long as it tastes proper. I don't buy Lucerne often though, because of that. I did discuss this with a dairy that supplies Lucerne in Yamhill County Oregon. They had no good info for me but were concerned since there milk go into the butter. Even though I take the risk and eat it, I wouldn't recommend it. I am still here, alive and well.

Never seen it myself but apparently it's been an ongoing concern in the industry for a hundred years or more. I found this clue in a 1915 report:

Wet surfaces, wet wrappings, or high humidity are essential to mold growth in butter. Mold will not grow upon the surface of a piece of butter exposed to humidities of 70 per cent or lower.

I google and google-scholared around and found quite a bit about molds on butter. I'd say that those brown spots are mold, and that everyone was right, you should take it back. Brown molds seem to be more common than green. I also saw quite a bit on bacteria (which can make it smell malty) and rancidity. Nothing about yeast contamination though.

If you try searching yourself, beware! Butter molds and yeast+butter have some more common associations!

I experienced this same situation with two different types of butter in the last 6 months. One type had brown spots when I opened it and another developed it shortly thereafter. They also had a cheesy smell. I took susan g's advice and contacted my extension service (Oregon) and the person I corresponded with contacted a college specializing in dairy and here is the response they gave:

It is possible to have molds growing on butter. I would recommend against eating moldy butter. The cheesy smell seems to indicate that there was yeast growing as well.

Which, I guess they're the experts, but I love to hear more detail. So there's both mold *and* yeast? I wonder if anyone would get more detail by contacting their extension service.

Well, I like to use Irish butter. The Irish can't afford to put spots on their butter. That's pretty political, yes?

It's time to start taking all these spotty butters back to the store, and ask for an explanation. Also, contact your board of health, contact your extension service. I had never heard of this, yet it looks like it's becoming common. Time for answers.

WTH? indeed! Are the spots just on the surface, or are they inside also? I did a quick web search and came up empty, except for this page from Farmers Journal, April 1910.

http://books.google.com/books?id=hNpGAAAAYAAJ&pg=PA210&lpg=PA2#v=onepage&q&f=false

It won't really help, but it might provide a nice diversion while you're putting your spotted butter in the trash bin.

It's January 12, 2011 - opened a box of butter this AM - and two of the sticks had same light brown spots... WTH? Back to "Whole Paycheck" it goes!

Yikes! What with worrying about what's in our air, water, produce, and meat, do we have to start inspecting our butter too?!

I just recently opened some butter with brown spots, I threw it out.I didn't know if it was good either.

I've handled uncountable pounds of butter, and have never seen any kind of spots on any of it. I agree with Merrill. Toss it out and buy fresh.

That sounds odd -- I'd probably buy fresh butter.