Fix three things before you ask for a price: the specification, the Incoterm and the volume with its call-off pattern. Quotes that vary on any of those are not comparable, and the cheapest number on the page is usually the one attached to the loosest specification.
Why it works this way
Frozen fruit price is a function of grade, defect tolerance, calibre, packaging, certification scope and delivery terms. Change the defect tolerance by two percent and the price moves more than most negotiation ever will. Change the Incoterm from FCA to DAP and you have moved freight, insurance and border risk into the number without changing the fruit.
The same applies to volume. A price for a single trial pallet and a price for a twelve month call-off are different commercial products, and a supplier quoting the second against the first will always look cheaper.
What follows in practice
Send one specification and one RFQ to every supplier, with the same delivery term and the same volume, and ask for the price to be broken into product, packaging and freight where the term includes freight.
Then score the non-price side on the same sheet: certification scope and validity, traceability depth, sample results against specification, and how quickly and completely each supplier answered. Writing an RFQ for frozen food sets out the fields that make replies comparable.