Earlier quoted context omitted.
You are aware that restaurants clean their food before cooking them? It's a major part of food safety. Indeed, because restaurants generally source their food from better sources than a regular consumer can (many times, straight from the farm), restaurant food is arguably safer than "raw" food you can cook at home. Thus, french fries from a restaurant would be at least as safe as french fries you eat at home. Another…
Where did you get that? Restaurants have paper-thin margins and strong incentives to use the lowest quality ingredients they can get away with.
But anyways: the number one operational cost that kills restaurants is leasing costs, not supplies or employee wages, because those latter costs can be managed based on the amount of business, time of year, etc.
And the truth about "high quality" versus "low quality" ingredients is that at the restaurant scale, the price difference isn't that large; excepting meat, it can be as low as 10% (and in some cases, at least in SoCal it can be cheaper to buy organic produce than nonorganic). I' still close friends with a number of food purchasers and suppliers in the SoCal area, and you would be absolutely shocked at how little restaurants have to pay for their produce and fish. Consequently, their isn't much of an incentive for a restaurant to use the lowest-quality ingredients because their isn't a significant cost savings but there is a huge risk associated with using lower-quality ingredients. (However, the calculus is different for food manufacturers, who sell their products at wholesale prices and so have significantly smaller potential margins.)