Tag Archives: Lifehacker

Leftover rice risks from Lifehacker

Posted on by
Reply

One of my former roommates was a straight edge punk-loving vegan for a while. Now he eats meat and drinks beer, but for a while he survived on rice and sriracha. Sometimes he left his steamed rice out overnight – making some egg-free fried rice the next day. This was before either of us knew much about Bacillus cereus and rice.

Earlier this week Claire Lower from Lifehacker emailed a couple of questions about leftover rice safety. The Lifehacker folks often ask really good questions about the science and why behind food safety recommendations – Claire included. Claire wanted to know why some guidelines say not to leave rice out on the stove over night.

I sent Claire a couple of papers including this one which is an oldie (1974), but a goodie from Gilbert and colleagues which included this awesome B. cereus spore/vegetative cell growth figure (right, exactly as shown) highlighting anincrease of a log or more within 4 hours once in vegetative state.

We looped Don into our discussion and he pointed out the somewhat common practice of boiled and then fried rice in some Asian cooking techniques.

According to Benjamin Chapman, Food Safety Specialist from North Carolina State University, cooking rice doesn’t necessarily kill all the pathogens that may be lurking about. “The issue with rice,” he explained to me over email, “is that one pathogen, Bacillus cereus, is quite prevalent in dried rice (some sources say ubiquitous), likely as spores. The spores may survive cooking. If cooked rice is subsequently held at room temperature, the spores can come out of their protective form, germinate, and vegetative forms multiply. The cooked rice environment provides a lot of water and nutrients for growth. As a by-product of growth, they create a couple of toxins, including a heat-stable one.”

Beyond refrigerating any home-cooked rice, a sense of vigilance is helpful when dining out. According to food scientist Donald Schaffner of Rutgers University, some restaurants “cook up a large batch of rice, hold it at room temperature all day,” and then take portions from the batch as needed. “Because Bacillus makes a heat stable toxin,” he explained “this is not a best practice, and has led to outbreaks in the past.” “Heat stable” means that the toxin can survive boiling and, once the rice is cooled into the “danger zone” of 59-122°F, the bacteria can multiply, making even more of the toxin. Sushi rice, he noted, shouldn’t be a problem as vinegar is added to lower the pH, allowing it to be held safely at room temperature.

Lifehacker covers the science of Thanksgiving

Posted on by
Reply

Lots of folks like to say that food safety in the home is simple. It isn’t. There are a lot of variables and messages have historically been distilled down to a sanitized sound bite. Saying that managing food safety risks is simple isn’t good communication; isn’t true; and, does a disservice to the nerds who want to know more. The nerds that are increasingly populating the Internet as they ask bigger, deeper questions.

Friend of barfblog, and Food Safety Talk podcast co-host extraordinaire, Don Schaffner provides a microbiological catch-phrase that gets used on almost every episode of our show to combat the food-safety-is-simple mantra; when asked about whether something is safe, Don often answers with, ‘it depends’ and ‘it’s complicated’. And then engages around the uncertainties.IMG_4138

Beth Skwarecki of Life Hacker’s Vitals blog called last week to talk about Thanksgiving dinner, turkey preparation and food safety and provided the platform to get into the  ‘it depends’ and ‘it’s complicated’ discussion. Right down to time/temperature combinations equivalent to 165F when it comes to Salmonella destruction.

Here are some excerpts.

How Do You Tell When the Turkey Is Done?

With a thermometer, of course. The color of the meat or juices tells you nothing about doneness, as this guide explains: juices may run pink or clear depending on how stressed the animal was at the time of slaughter (which changes the pH of the meat). The color of the bone depends on the age of the bird at slaughter. And pink meat can depend on roasting conditions or, again, the age of the bird. It’s possible to have pink juices, meat, or bones even when the bird is cooked, or clear juices even when it’s not done yet.

So you’ve got your thermometer. What temperature are you targeting? Old advice was to cook the turkey to 180 degrees Fahrenheit, but that was a recommendation based partly on what texture people liked in their meat, Chapman says. The guidelines were later revised to recommend a minimum safe temperature, regardless of what the meat tastes like, and that temperature is 165. You can cook it hotter, if you like, but that won’t make it any safer.

There’s a way to bend this rule, though. The magic 165 is the temperature that kills Salmonella and friends instantly, but you can also kill the same bacteria by holding the meat at a lower temperature, for a longer time. For example, you can cook your turkey to just 150 degrees, as long as you ensure that it stays at 150 (or higher) for five minutes, something you can verify with a high-tech thermometer like an iGrill. This high-tech thermometer stays in your turkey while it cooks, and sends data to your smartphone. Compare its readings to these time-temperature charts for poultry to make sure your turkey is safe.

The whole piece can be found here.