Final answer:
The correct answer is option 4) "We make our cheese with only the freshest unpasteurized milk".
Step-by-step explanation:
The statement from a dairy supplier's sales brochure that should discourage you from hiring the supplier is: "We make our cheese with only the freshest unpasteurized milk". According to Microbiology: A Laboratory Experience, raw or unpasteurized dairy products contain deadly microorganisms and should not be consumed.
Additionally, methods like high-temperature short-time (HTST) pasteurization, and ultra-high-temperature (UHT) pasteurization are used to ensure safety by reducing bacterial numbers, while either preserving the milk's quality or allowing long-term storage without refrigeration, respectively. Using unpasteurized milk goes against the standard practices meant to safeguard health.