Shipping frozen produce - yes indeed
In regards to methods - frozen containers / trucks / airfreight containers
Basically, the shipping temperature needs to ensure, that the product remains in frozen throughout the whole transport chain
Depending on:
From where to where are you shipping? That will determine your mode of transport
Once you have the mode of transport, then you can see, which 3PL (3rd party logistics providers) offer a cold chain solution - that is the one you want (as this generally includes temperature and humidity tracking throughout the whole transport).
Are you exporting to another country?
Then it will be important to check the import requirements (i.e. what are the requirements to import frozen produce?)
While that generally would be your customers job to handle that part, it could be, that certain analysis / health certificates are required, which of course would then be the job of the supplier (so your job) to get those documents ready
Used to work for a company that exported frozen pastry products from France all over Asia
We shipped them in 40' reefer containers (set at -18 C) with humidity and temperature sensors monitoring any variances.
Upon receipt of the container, a temperature check (3rd party) was done at port to ensure, the products where still at -18 C
Into a frozen truck it went to the warehouse, directly into the frozen storage section.
Delivery to customers again in frozen truck.
Hope that I was able to give you some insight into it - any questions do let me know