You let Fido lick your plate: mostly ok

If you don't have pets, just move on, nothing to see here. But if your furry friend moonlights as a living, breathing garbage disposal and licks from your dishes, is that horrible? (Asking for a friend.)

Turns out the more serious risk is that they can be “ingesting products that may not be good for their digestive system,” Dr. Gravani said. So be careful what you're feeding them. As for the human members of the family? “We really want to do a good job of cleaning,” he said, but as long as we're washing dishes on a sanitation cycle — or high heat of 160 degrees — breathe easy. “It's ok,” he said.

We're not the only ones who need our dishes sanitized, though. Pet bowls were found the be the fourth germiest thing in the house and they should be washed daily. Yep, daily, and if you're handwashing them they need weekly sanitation.

You had last night's pizza for breakfast — after it sat out all night: risky

“You know what the USDA says,” Dr. Gravani said. “There's nothing magical about pizza. Anything over two hours at room temperature should be discarded.” So why is this such a prevalent practice? “What usually happens is some people don't see any adverse effects so they think it's ok,” he said. But just because you've been lucky so far doesn't mean you're home free. “Organisms that cause foodborne illnesses varying from very mild to significant” can be lurking there with your olives and pepperoni. To be on the safe side, just cram the box into the fridge.

“This is so confusing to most consumers,” Dr. Gravani said. “They have no idea what these designations mean. I sure hope at some point we can get a handle on getting people's definitions.” In the meantime?

“Every product has a usable shelf life and at some point the quality begins to deteriorate and that's usually what these dates mean,” he said. “You can eat some of these after the dates but use your senses. If it's significantly lacking in quality you don't want to consume it.” That's a little murky though. Gravani agrees.

“The keeping quality of food still mystifies people because they have no clue.” The good news is there's help available on your phone. Gravani and Cornell worked with food safety partners like the USDA to develop a free app called the Foodkeeper. “It's pretty cool,” he said. There's “basic information about dating but also a rough idea of the keeping quality of a variety of foods. It's really a great app to get a sense of how long folks can keep something.”

You grill your steak and put it back on the same platter: very risky

That happens more than you think, Dr. Gravani said. He's seen it, in fact, when at a barbecue “someone brings out raw meat on a platter and wants to put the cooked meat back on it. I quietly walk the platter back to the kitchen.”

“Certainly raw foods of animal origin contain pathogens,” he said, so letting food you're going to eat touch raw meat is a definite no-go. Not only that, he added, you've got to cook it thoroughly. “How many people have thermometer? Slim to none so it's all eyeballing and we know undercooked hamburger causes illness.” And that holds true whether or not you know where the meat's coming from, he said. “Bacteria doesn't know the difference in a small or medium or large farm, or organic or conventional.”

Ahh, the good old five second rule. Dr. Gravani's former student and good friend Donald Schaffner, a food science professor at Rutgers University, is a risk modeler who set out to get to the truth about that old adage. “He looked at four different surfaces and four different foods and he inoculated the surfaces and he dropped the foods for a fraction of a second, less than five seconds, five seconds, and an extended time,” Dr. Gravani said.

“The bottom line was the longer the contact the more bacteria so the five second rule is kind of an oversimplification of what happens when bacteria transfers to food.” But, here's the key. “No matter which food or which surface, they saw bacterial transfer. There was no safe amount of time to leave food on the floor and it is never completely risk free.”

So why do we do it? Just like with the pizza phenomenon, “if people drop it and dust it off and eat it with no consequence that's a learned response,” he said. “But from a microbiologist point of view that's a bad news situation.”

The worst thing most of us do every day

What's the biggest thing we're all doing wrong? According to Dr. Gravani, “the most important thing is just the simple act of handwashing. What a lost practice.”

Before handling food or eating we need to wash our hands for 20 seconds, he said. “It's [singing] Happy Birthday twice.” And that's the hard and fast rule at his house. Even when friends come over to eat, “we say we have a rule … we march everyone to wash their hands.” If we could just bring that practice back, he said, “I think that would reduce a lot of hassles.”

So should we all be aiming for a completely sterile kitchen? Of course not. “I don't think anyone is advocating for operating room conditions in your kitchen,” Dr Gravani said. “What we're saying [is] across the board, the food agencies and health and agriculture departments, let's reduce the risk, there are some common practices we can use. These pathogens are all around now and organisms that we never thought about 20 years ago are now household names. We can still enjoy our food — remember it's social, it's about enjoying the moment and you don't want to make that a sterile lifeless situation. Have fun but do it safely.”

And with that, I'll go wash my hands.

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