If there was any doubt about whether the eggs were dangerous, maybe she should have waited until she knew for sure. But considering that this was an issue that dealt with human health and safety, I think she acted with the best interest of her people in mind. She made the best decision she could make with the information she had on hand.
British politician Edwina Currie is perhaps best known for her allegations that her country's eggs were tainted with salmonella. The claim ushered her out of office in disgrace, but it was later found that she was right and that the salmonella poisoning had been covered up. Sometimes politicians can be a canary in the coal mine, even if they are viewed at the time to be making false claims.
Causing a nationwide panic is a reasonable excuse to fire someone. As the Prime Minister, you are the representative of an entire nation. Therefore, not knowing what you are talking about when addressing the nation should not only be discouraged but should also be alarming. If a nation's leader can be misguided on an issue such as salmonella, they can be misguided when making the most important decisions.
It is irresponsible to give the public incorrect or unverified information about health risks. Whether it's a theory or an outright lie, releasing this kind of information on a public platform is dangerous because it can cause mass hysteria and damage another's business. It is always important to fact check.