Grocery Shopping in Italy is something no one thinks about until they are in Italy.
Here are some tips for you.
When choosing produce you MUST use plastic gloves.
Every region in Italy is different however in Tuscany, I always saw people using the gloves. When in doubt, use them.
Next, once you choose your veggies, you must weigh your produce yourself. In the states, it's the opposite, you bring your veggies in a bag and they weigh it for you when you check out.
Each vegetable and fruit has a number listed and you take that number to the machine that prints out the price, weight and barcode of your produce. It very simple. You just have to remember to do it. If you get the cashier without weighing it first you will be sent back to the machine next to the produce.
In open air markets like Mercato Centrale e Mercato Sant'Ambrogio it's the opposite. You will point to or say the fruit or vegetable you'd like, how many, and they will weigh it for you. DO NOT TOUCH the produce at an open air market. It's rude and not what people do.
I recommend bringing your own tote bag or a reusable shopping bag from home. Know that plastic bags in Italy cost. Not a lot, around .3-.5 cents but still, let's try to keep saving the environment and bring a reusable bag for your shopping needs.
Regarding produce, another good tip is to always (if you have one near your apartment, hotel or B&B) purchase from an open air market. It's usually cheaper than going to stores like Esselunga, Coop, Conad, & Carrefour Express. The produce is usually better looking, more delicious and think about supporting small businesses. Some of the vendors come from outside of Florence to sell their own produce. Support them if you can.
Lastly, bring your dictionary with you to the store or market. Try to speak in Italian if possible when talking to a fruttivendolo (greengrocer). Vorrei una mela (I'd like an apple). Use the dictionary when you are in the grocery store too. This will help you understand where your favorite Italian staples are in the store and perhaps you'll finally learn you love Scamorza and now you know it's a similar type of smoked mozzarella. YAY!
Hope these tips will help you when you are shopping in Italy. Prego!