In the produce cooler section of stores (such as Costco), one can often find packages of shrink-wrapped cut up veggie and fruit platters. Would the fact that these are precut in the store require kosher certification or can they be considered kosher since they are only fruits and vegetables? Please include consideration of the utensils used for cutting the fruits and vegetables.
Here is an answer from Rabbi Eli Gersten from a previous issue of Jewish Action (OU):
If your co-workers bought a fruit platter from a supermarket, you may partake of the fruit since you can assume the supermarket has a dedicated knife for fruit platters. Additionally, due to the sheer volume of fruit cut at one time in such a scenario, we regard the knives and surfaces as clean. The same applies to precut watermelon sold in supermarkets; there is no need to trim the edges.
However, if the fruit platter came from a nonkosher restaurant or caterer, it is questionable whether you may partake of the fruit, since a single order might be prepared with a nondedicated knife or on a dirty surface or with the chef’s greasy hands. In this case, the fruit will require washing.
The halachot of cut salads (assuming there is no concern of insect infestation) would be similar to what we discussed above regarding fruit. Sliced onions, radishes, lemons or any other spicy fruit or vegetable should be avoided, unless it is clear that they were cut in great abundance, in which case all the problematic onions or lemons would be batel.
If the OU just doesn't cut it for you (pun intended), here's a tweet from the CRC:
One may purchase cut raw fruits/vegetables (with no bug problems) from a large supermarket with no hechsher
The original source of the case of non-Jew cutting multiple lemons is found in the Shulchan Arukh, Yoreh Deah 96:4:
מֵי לימוני''ש שֶׁמְּבִיאִים הָעוֹבְדֵי כּוֹכָבִים, וְכֵן חֲתִיכוֹת דָּג מָלִיחַ שֶׁמְּבִיאִים הָעוֹבְדֵי כּוֹכָבִים בְּחָבִיוֹת, מֻתָּרִים. הַגָּה: מִפְּנֵי שֶׁמְּבִיאִים הַרְבֵּה בְּיַחַד, וְאַף אִם נֶאֶסְרוּ מִקְּצָתָן שֶׁנֶּחְתְּכוּ בָּרִאשׁוֹנָה עִם סַכִּין שֶׁל גּוֹיִים, נִתְבַּטְּלוּ בָּאֲחֵרִים הַנֶּחְתָּכִים אַחַר כֵּן, שֶׁאֵינָן נֶאֱסָרִין, כִּי כְּבַר נִתְבַּטֵּל טַעַם הַסַּכִּין בָּרִאשׁוֹנִים וְלָכֵן כֻּלָּם מֻתָּרִים. וְכָל כַּיּוֹצֵא בְּזֶה (בַּיִת יוֹסֵף בְּשֵׁם שִׁבּוֹלֵי לֶקֶט). וְלָכֵן אוֹכְלִין בִּקְצָת מְקוֹמוֹת הַכְּרוּב שֶׁקּוֹרִין קומפש''ט, אַף עַל גַּב דְּפָרוּס וְחָתוּךְ. וְיֵשׁ מְקוֹמוֹת שֶׁמַּחְמִירִין בָּזֶה, וְאֵין לְשַׁנּוֹת הַמִּנְהָג (מהרי''ו סִימָן מ''ט), אֲבָל שְׁאָר דְּבָרִים שֶׁאֵין חֲרִיפִין, כְּגוֹן תַּפּוּחִים אוֹ לְפָתוֹת יְבֵשִׁים וְכַדּוֹמֶה, נוֹהֲגִין בָּהֶן הֶתֵּר כְּמוֹ בלימוני''ש וְאֵין לְהַחְמִיר כְּלָל (בְּאָרֹךְ).
Alright, this answer is to get DanF started, but it could be a general answer too. I am putting it here because pics can't be uploaded to comments.
This is the answer to almost the exact question asked in Rabbi Eli Mansour's book, Daily Halacha, which is published through Artscroll. It doesn't give any primary sources (which is a bummer), but it should get you started. I'm just way too swamped at the moment to write a proper answer myself, but plan to in the next week or so, beli nedher. Good luck on getting your heter for tomorrow's shopping trip, although this is fairly standard halakhic procedure and even those who are mahmir about just require a rinse prior to consumption.
The Shulchan Aruch says one can, in theory, assume they were cut with a designated vegetable-only tool.
(If they were cut with a dirty, non-kosher knife, then the first ten or twenty cuts would still be not kosher, but at some point that peters out.)
As always it's better to get something with a kosher certification. But at least in theory, pre-cut fruits and veggies coming from a large produce facility were likely done on dedicated equipment -- or at least by the time they cut your produce, most likely the knife doesn't have any traces of non-kosher on it.
The melon cut in-house at a Korean market, on the other hand, is an example of something I would avoid. You know they're processing non-kosher stuff right there, and they don't have the same kind of produce volumes.