One recent summer evening, while entertaining some friends, my husband and I assumed our usual roles at the backyard barbecue. He was manning the grill, cooking up burgers, fish and chicken. And I was being the too-careful food safety dietitian, immediately replacing his raw-meat-holding tray with a fresh one, and using my handy meat thermometer to test the internal temperature of the cooked goods.

You see, once you’ve been schooled in microbiology and critical control points for avoiding salmonella and E. coli, there are some rules that you never forget. And when I have company over for dinner, my training kicks in and I’m extra careful about keeping the hot foods hot and the cold foods cold. What would be more embarrassing than a dietitian accidentally sending her guests home with food poisoning?

I do get a lot of ribbing about my aggressive food safety habits. On this particular evening, my friend Layla* was laughing at the huge digital meat thermometer that was testing the “doneness” of our repast. Said Layla: “You don’t need that thing. I never use one. You can just tell when burgers are done.”

I felt a bet coming on. Could she really predict doneness of a burger? We put a little wager on it --$20 to the winner -- and Layla had the task of telling my husband when to remove her “so-she-thinks” perfectly cooked burger. When Layla gave the green light, my husband flipped a burger on the (clean) tray. Layla guaranteed me that the burger was done and said she was so confident in her decision that she’d feed this burger to her two sons, aged 3 and 5.

Now, before I reveal the results, let’s discuss why this is such a critical issue. Ground beef is the main carrier of harmful E. coli, a bacterium that can cause food poisoning if ingested. Meat that’s contaminated with E. coli still looks and smells normal.

While the surface of any meat can technically harbour E. coli, it is killed when you cook food at a high temperature. If E. coli is on the surface of a steak, it is killed by the grill, even if the inside of the meat stays pink. However, burgers made from ground beef are different. Bacteria can be spread during grinding, so E. coli can be anywhere on the surface OR the inside of the burger. It’s vital that both the outside AND the inside are cooked to a temperature of 160 F (71 deg C).

The results...

I could see this statistic glaring at me from the pages of my text book: “One out of every four hamburgers will turn brown before it has been cooked to a safe internal temperature.” The meat thermometer was inserted into Layla’s hamburger and the beeps began. 110... 120... 130... I started to think I may lose this bet after all. Soon, 140... 145... 148... then... nothing. It stopped at 148 – a full 12 degrees short of safe.

Layla was shocked – and was quite shaken when she realized that she was actually endangering her sons by not using a meat thermometer. While E. coli can cause extreme cramps and bloody diarrhea in adults, it is even more problematic for young children. Kids under age five can develop an E-coli-related complication called hemolytic uremic syndrome, in which the red blood cells are destroyed and the kidneys fail.

Needless to say, her kids did NOT eat that burger until it went back on the grill for a few more minutes, and a valuable lesson was learned. And I took the $20 that I won from the bet and spent it on a new digital meat thermometer for my good friend Layla.

Keep your barbeque safe by remembering these tips:

1. Start with clean hands, and wash often as you prepare food.  This is especially vital when your ingredients include raw meat, chicken and eggs.
2. Understand marinade etiquette. Step one: marinate food in the fridge. Step two: throw out marinade that was used on raw meat or poultry – do not use it on cooked food. If the raw meat bathed in it, consider that the bacteria from the meat is now in the marinade. Toss it out and start fresh.
3. Invest $20 in a digital food thermometer and measure the internal temperatures:
   • Hamburgers - 160 °F
   • Roasts and steaks - 145 °F medium rare or 160 °F medium
   • Poultry - 165 °F
   • Here's a full list of proper cooking temperatures for other foods
4. When taking foods off the grill, do not put cooked food items back on the same plate that held raw food, unless it has been washed with hot water and soap first.

 * names changed to protect the embarrassed parties