[she says to everyone asking her for “independent third-party testing” because they don’t believe her test results!]
Independent testing by an organization that was not involved in the design and implementation of the object being tested (e.g., a system or device) and is not intended as the eventual user of that object.
“Party #1”: The manufacturers
“Party #2”: The customers/consumers
“Party #3” (a.k.a “third-party”): Someone who has no financial interest in the product or the outcome. Someone who is not the customer or the manufacturer — someone who does unbiased testing, using science. A third party.