Add a little oil, and a few minutes in a frying pan or microwave will do it. Maillard reaction (browning) starts at around 140°C and shiitake aren't exactly thick, so they won't take much longer than it takes to get some extra colour on them. Average frypan and oven temp is usually around 180°C, so it's not something you really need to think or worry about.

They also think you need a certain hypersensitivity for this to happen. If this were a significant risk, there would be huge amounts of cases in East Asia. This case became a science tabloid spam piece because it's so unusual.

Easy. Just pressure cook it at 4.5 bar (65 Psi) in your industrial grade pressure cooker.

Being realistic, I guess someone accidentally swapped Celsius and Farenheit?

EDIT: Nope, seem to be wrong. They do mean 145 degC. On the other hand, I found a source reporting that 57 % of a total of 58 cases of shiitake dermatitis actually thoroughly cooked their mushrooms. Cooking won't save you from this, as it seems.

Study: Ha, JH; Byun, DG; Kim, SM; Yoo, CH; Park, CJ (2003): Shiitake dermatitis in Korea; clinical and histopathologic study. Korean J. of Dermatology, Vol.41 (4),pg 440 – 444

Thermite

Average stove gets to around 350°C. Electric can go to 900. Gas up to 2000, depending on the mixture used.