On all-natural peanut butter
Hi! Can all-natural peanut butter remain in the pantry forever? Even if all the oil appears to be gone? I have been working on the premise that it can, if I don't see any mold. But I've never seen any mold.
Theoretically, yes. There’s not enough available water in your peanut butter for harmful bacteria to grow. When PB gets contaminated, it’s generally because of user error (aka you shoving an unwashed finger into the jar for a furtive midnight swipe.)
Now, you’ve described a scenario in which “all the oil [in your peanut butter] appears to be gone.” It’s possible that the oil simply oozed back into the peanut butter. But I’m guessing that someone, perhaps you yourself, skimmed away all the good oily peanut butter and now you have a jar of nut paste with the consistency of asphalt. Give your peanut butter a stir and see if it returns to normal consistency.
No? Well, it should still be safe to eat. If you get the urge to doctor your peanut butter back to a more agreeable consistency, stir in a dollop of vegetable oil and see if that smoothes it out. I’ve never done this before but it’s scientifically safe. Try it! Let me know how it goes. (Personally I don’t go for peanut butter that requires stirring— I’m a Skippy™ girl.)
Finally, a cautionary tale. My sister once admitted to me that she habitually ate the “oily layer” of peanut butter off the top of her jar and then would add water to the remaining peanut butter in order to restore moisture to it, all while keeping the jar unrefrigerated. This is the food safety equivalent of going over Niagara Falls in a barrel. Adding water to peanut butter effectively turns the entire jar into a petri dish of scary pathogens. I honestly can’t believe my sister is still alive.
But you don’t have to worry about this. It sounds like you’re a great custodian of peanut butter.
This dog has a death wish
Ever wonder why you don’t have to refrigerate fudge?
+++++
On cooking sketchy food more
Should I be adjusting the cooking temperature of my food based on where I buy it?
This is a tricky one. First, let’s review a primary law of food science: higher temperatures kill bacteria faster. This means that you can reduce the bacteria load in your food by cooking it for longer and/or at a higher temperature.
If a raw hamburger happened to slip from my spatula onto the ground, I’d unhesitatingly scoop it up, brush it off, and throw that bad boy on the grill. The heat will nuke any bacteria.
But your question requires a more nuanced analysis. Let’s say you buy two physically identical steaks. One is from a steeply discounted butcher operating out of a leaky boxcar under the Manhattan bridge. The purveyor, a grizzled nine-year-old with a smoker’s cough, assures you repeatedly that it’s “cow.” The other steak is from Eataly or Blue Hill or whatever.
Should you cook the sketchy steak more to offset the gargantuan bacteria load that we can assume it carries? Conversely, can you gently sear the gourmet steak and enjoy its medium-rare perfection without fear?
Basically...it depends. Sorry, I know you wanted an easy answer.
There are a thousand opportunities across the supply chain for raw meat to be compromised. A drunk slaughterhouse employee nicks a cow intestine with his knife while he divides the carcass, thus splashing your steaks with literal shit. A leaky ceiling drips onto the conveyer at the assembly line where cuts are packaged. The refrigerated truck transporting your steaks isn’t quite cold enough. Any of these things would cause the bacteria count in a steak to spike long before it reached whatever meat trader you patronize.
My local butcher
It’s impossible to convert these intangible risks into any practical cooking instruction. But there is a correlation between food quality and reputable establishments. That’s one reason why the bougie steak at Le Artisanal Butcherie costs more than the slab at Todd’s Meat Shed. Cut-rate butchers are more likely to work with uncertified distributors and be less discerning about their meat. Upscale butchers are more likely to demand accountability from suppliers. These are probabilities, not guarantees.
Here’s what I recommend: when it comes to the top 1% of meat, you can comfortably flout standard food safety practices. When your farmer friend butchers a cow and hand-delivers the choicest cut to your door, rare is the way to go.
On the other hand, treat the bottom 99% of meat with a bit more caution. But just a bit. Don’t overcook your steak because you bought it under a bridge and the guy wrapped it in pages torn from a 1998 issue of Sports Illustrated—cook it like you’d cook the steak you bought from ALDI or Stop & Shop. It’s probably fine. Heat kills bacteria.
My only caveat is psychological. I mean, if you buy low-quality ingredients and try to compensate with cooking tricks, you won’t get sick. Even without the tricks. But is the delight of buying “99-cent lobster” worth the unrelenting suspicion that you actually just ate dozens of delicately-glued, dip-dyed cockroaches? Only you can decide.
+++++
On not refrigerating fudge
How come you don't have to refrigerate fudge? It has both milk and butter in it...
You can’t see it, but a sinister grin is slowly spreading across my face. With your innocent fudge query, you have surfaced one of the most crucial concepts in food safety.
First, let’s examine fudge. Fudge is delicious. It is delicious because it is really sweet and really fatty, as well as kinda salty. For science reasons, water clings tightly to molecules that are sweet, fatty, and salty. When the water content in a food is chemically-bonded like this, we say that the food has a low water activity.
Why does low water activity matter? It matters because bacteria is thirstier than a 23-year-old Goldman Sachs associate at an East Village bar. Bacteria needs water to live and it can’t access water that is chemically bonded to something else—such as sugar, fat, or salt. When there’s no available water in a food, then that food becomes inhospitable to bacteria. Low water activity foods are the equivalent of a lesbian night at that East Village bar: the Goldman associate can try all he wants, but he’s not getting in. Sorry, buddy. Private event.
If you have a food that’s sweet enough (Nutella) or fatty enough (olive oil) or salty enough (soy sauce) or, in the tastiest scenarios, some combination of all three (fudge), then there’s no water available for the bacteria to drink. No available water = no possible bacteria growth.
One last thing. You might be thinking: “Wait a minute, fudge—at least the way my grandmother makes it— is nice and moist. How can such nice moist fudge have a low water activity?”
I’ll tell you why. Water activity isn’t the same as moisture content. It is possible for a food to be moist but still have a low water activity. Peanut butter is a perfect example. You don’t have to refrigerate that, either.
+++++
On when to refrigerate hot food
How long after cooking something should I wait to refrigerate it?
When I worked at a food processing plant I would arrive at 6 a.m. and do a facility walk-through to spit and pee in all the food (just kidding: to inspect equipment and prepare for the day’s production). One fine morning I discovered a 30-gallon pot of béchamel sitting in the main walk-in. This was odd. All of the walk-in refrigerators should have been empty. I pulled back the lid and a puff of buttery steam escaped. I exited the walk-in and called out into the twenty-thousand square-foot production floor. There was no answer.
Somebody had woken at dawn to make a 400-pound batch of macaroni and cheese. But who? I considered the options.
Option one: Sam the sous chef was getting stoned and pulling all-nighters again.
Option two: The béchamel had been prepared the afternoon before... and was still blazingly hot after more than 12 hours in the refrigerator.
If you guessed option two, you get an expired cookie. A pot of piping béchamel weighing more than a baby elephant will, in fact, take forever to cool in the refrigerator. An industrial stock pot could take days to fully cool. A big metal pot will do a great job of insulating its contents and this is no bueno because bacteria will grow as the food lingers in the “danger zone.”
That’s a lot of béchamel
There’s also a second issue with putting hot food straight into the fridge:
When you sock away a still-steaming Le Creuset full of béchamel, all that heat will quickly raise the temperature of your fridge. The condenser will start chugging away to restore the chill, but that could take hours. In the meantime, your fridge could be hovering at a subtropical 60º, which would encourage rapid bacteria growth and shorten the shelf-life of every single item.
Also, all that steam coming off your béchamel will eventually turn into fridge frost. There’s nothing wrong with fridge frost but I find it unsightly. I don’t know what to say, it’s just not who I am.
So: let your hot food cool off naturally on the countertop before you begin the “active cooling phase” (industry term!) in the refrigerator. But for how long? It’s easier to measure by temperature than time, but aim for 30-60 minutes of countertop cooling. The food should be somewhere between lukewarm and warm—definitely not steaming— when it goes in the fridge. If that’s not happening within an hour, try these tactics:
Transfer the food into smaller containers. If you’re parceling out meals for the upcoming week, this is a convenient time to make that happen.
Leave the cooked food uncovered. (It’s okay, you have my permission.)
If you’re cooling soup or stew or something thick, give it an occasional stir to release heat.
Oh, and if you’re wondering what happened to the massive pot of béchamel...we trashed it. There were 800 portions of mac & cheese going out that day. We couldn’t afford to make 800 people sick.
Me after I pilot some food out of the danger zone
+++++
On expired sour cream
Sour cream, two weeks past expiration date. OK to eat?
Yesterday I unearthed a carton of 2-week-overdue sour cream in my refrigerator and posed this exact same question to myself. My sour cream was unopened, so I unwrapped it and gazed into the white abyss. I found no suspicious discoloration or sinister odors so I shoveled a heap onto my breakfast nachos. It tasted like sour cream. I happily returned the rest of the carton to the fridge.
The most likely scenario for sour cream “going bad” is that you, the user, contaminate the container with bacteria and that bacteria interferes with the sour cream’s own fermentation. It logically follows, then, that to maximize the shelf-life of your sour cream, you want to minimize the introduction of new bacteria: Spoon your sour cream with clean utensils, don’t double dip, keep the lid clean, don’t lick your finger and swirl it around that creamy whirlpool simply for the thrill of it. These practices will make your sour cream last much longer — perhaps weeks past the expiration date.
How do you know when it’s finally time to throw away your sour cream? Use your senses. First, don’t be deterred by a little separation — just give it a quick stir and it should reorganize into its familiar consistency. Second, don’t eat any sour cream that shows signs of mold or color change. Third, smell it. Contrary to the name, sour cream has a pretty smooth fragrance. If you whiff something putrid (trust me, you’ll know) then throw it out.
For more hot tips on fermented dairy, dip into this post on expired buttermilk.
+++++
On eating the party spread the next day
My question is about the general detritus of a party spread discovered the morning-after. Is it all too far gone for a nibble? In this state of mind everything looks poisonous... But can anything have actually gone bad during that time?
We both know the best way to outrun a hangover is to get some food in your stomach, rehydrate, and flee the scene of the party before demons overtake you. Since I’m usually the first to wake up after one of our Dutch-Romantic-Era themed rituals, I get first look at the day-old spread. Here’s my approach:
We’ve all been here before
Hunk of bread: It’s kinda stale but no mold — totally safe. Christ, I need something to sponge up all that wine. Eat.
Olives: Don’t mind if I do. Let’s leave these out until noon and then feed them to the pigs. Eat.
Chalice of wine: Oh heavens yes! I mean, given that the wells are riddled with cholera, this is probably my safest bet at rehydrating. Drink.
Those half-eaten flagels: I worry that they were handled by unclean hands last night. And is that meat filling? Let’s avoid half-eaten foods and meats. Do not eat.
Roasted goose: Left unrefrigerated for 12 + hours? I just barfed a tiny bit into my mouth. Do not eat. Trash the goose. No, no, don’t throw it away. Give it to the stable boy.
Peacock pie: This looks horribly unsanitary and I don’t like the way he looks at me. Please just take it away. Do not eat. I don’t care just take it away.
Dried confections, nuts, and fruit: No worries about this stuff. I’m going to fill my cloak pockets for a snack on the carriage ride home. Oh my darling Johanna will be so delighted for a peach and Hendrik will finally taste his first apple! Eat.
Want more? I also wrote a post specifically about leftover pizza
+++++