The peels roll up and taste like paper.
Plus, that is where most of the bacteria is. No, you cannot ever safely use fresh lime or lemon juice. Only bottled is used since it must be a standard ph in order to be sold. Fresh vary and you have no way to know the ph level of them. You can use bottled lime instead of bottled lemon, though. Yes, you can omit cilantro.

I don't peel my green tomatoes. First of all, I find it near impossible to peel them - the boil and plunge doesn't work. I've never had an issue with the skins of green tomatoes; red tomatoe skins become papery and leathery, but not green. Just wash the tomatoes well.

Linda Zeidrich did some testing and found little difference in the acidity levels of fresh versus bottled lemon juice. So I would say the fresh lime juice is fine. Your aversion to risk may vary.

Here is a link that might be useful: Real Lemon versus ReaLemon

Linda Zeidrich has her own method and testing... however, the USDA states it must be bottled lemon juice or bottled lime juice to be safe. Otherwise you are just guessing those fresh limes or lemons are acidic enough.

isn't there also some issue with shelf stability? meaning juice from fresh lemons may become less acidic as it sit on the shelf? Maybe it's because of the acetic acid combined with teh citric acid, I'm pretty sure acetic acid is not shelf stable.

If that is the case, the acid level from a fresh lemon will drop over time as the acetic acid portion breaks down.

The only way to get a valid test is to test the acid levels before and AFTER storage, so see if the after ones are still good. But then you also have to do many, many tests to get statistically valid numbers. One person testing 20 -30 lemons is meaningless for statistics.

You don't need to peel green tomatoes and I don't believe the recipe calls for doing that.
You DO need to use bottled lemon or lime juice.

Deanna

thanks all. the recipe did say chopped, cored and peeled green tomatoes and I was dreading that so I think will leave the peels on and go buy bottled lime juice

Kerry, I like to peel my ripe tomatoes for canning purposes, but I never peel the green ones for salsa verde and we can't tell that the peel is even there.

Judi