It isn’t always easy to tell if a dairy product has just barely passed its prime or if it has started the descent into something unspeakable. It’s especially tricky when lots of tasty dairy treats have funky tangy elements to them, even when they are at their best. When to ditch shady dairy is, mostly, a matter of taste. Dairy that has  past its prime  deteriorates in quality; typically it won’t make you sick. (The same is not true for eggs.) Still, knowing what to look for and how spoilage occurs in dairy and eggs might just help you store & organize a teensy bit better so that you can avoid spoiled milk and moldy cheese. Milk and eggs are expensive, labor intensive food products. Keeping an economical kitchen definitely means looking after these precious ingredients with a high degree of care.

A quick note about expiration dates: these are the dates by which the industry suggests that theoretically, the product is at its best. In practice, there are a lot more variables involved. If a product has been stored with an abundance of care along the whole processing route, it might be good well beyond the expiration date. Conversely, a forthcoming expiration date doesn’t guarantee freshness. I’m noting very general shelf life for different milk products to help understand the process of spoilage and help figure out how to buy strategically. You should always rely on your senses over any expiration date or shelf life suggestion. Take a good look (and sniff) of products before and right after you buy them. When you are really familiar with how a product should look, you’ll have much more confidence knowing when it’s gone bad. It’s also good practice to follow the first-in first-out rule. That means using up all of the oldest product, before moving on to a newer container.


Milk:

opened: less than a week. unopened: one to two weeks

The root of all dairy products, milk itself, is the quickest to spoil. And the lower the fat, the quicker your milk will sour. Products made from milk have almost always startedout as a way to extend milk’s shelf life in pre-refrigerated kitchens. Culturing, curdling and salting all extend milk’s shelf life so that it’s tasty goodness and nutrients can be enjoyed longer.

The best way to make sure that your milk doesn’t sour before you use it all is exercise good judgment about how much milk to buy, and how frequently. Light, heat and air are your enemies with regard to milk spoilage. So if you have gallons or half gallons of milk that are getting sour before you finish them, try buying two cartons half the size. The unopened carton will stay fresh longer.  Ideally, milk should be stored in the coldest part of your fridge. So avoid the door and the top shelf.

Butter & Cream:

Cream: up to 2 weeks. Butter (unopened): several months. Butter (opened): 2-3 weeks. Butter (unrefrigerated): up to a week

The high fat content of butter and cream allows them to keep longer than plain old milk. But fats tend to pick up flavors from their surroundings. So make sure that you don’t have anything with a strong flavor stored right next to your butter or cream. And always seal containers well. Because the fat particles in cream rise to the top, it is perfectly normal for cream to have a solid layer on top, or chunks. Just shake the container well to redistribute the fat throughout the cream. Partly used cream can tend to get sour and funky smells if some of the solids are sticking to the top of the carton, where they dry out and are exposed to lots of air. If you have partly used cream, it is a good idea to transfer it to a clean container, rather than keeping it in the same carton.

With more of the moisture removed, butter keeps even longer than cream. And the longest keeper is ghee, Indian clarified butter, which has some of the milk solids and even more moisture removed. Ghee is typically never refrigerated.   You can keep butter out unrefrigerated, for up to a week. Just make sure to keep it covered and in a non reactive dish (no metals, except for stainless steel, please). Butter left out too long will eventually go rancid and the aroma will have hints of must and blue cheese.

Yogurt, Buttermilk,  Sour Cream & Creme Fraiche:

(2 weeks)

Culturing milk introduces beneficial bacterial cultures into the milk. These relatively stable and healthy bacterial cultures will make the product less likely to fall victim to bacteria that causes spoilage.  I like to make a note of when I purchased the product on the container. As with soft cheese, any visible mold is a cue to ditch the contents. The tricky determination is when something just seems a little off. Off smells can sometimes come from small portions of the culture that have dried (and started to go bad) around the edge of the container.  Smell and taste a small portion from the center of the container. If it is still good, scoop the contents into a clean container (avoiding the top outside) and use within a day or two.

Soft Cheese :

(1-2 weeks)

The high moisture content in soft cheese makes it susceptible to mold and bacteria. With soft cheeses, any visible mold means it is time to go. The mold has already penetrated much deeper than you can see. For soft cheese, it’s best to only buy what you can use up within a week.

Blue Cheese:

(1-2 weeks)

How can you tell if cheese that is supposed to look moldy is going bad? Look for changes in texture– soggy, slimy areas are a bad sign. As with soft cheeses, it’s best to buy right before you plan to use it

Hard Cheeses:

(2 weeks-1 year)

Hard cheeses are much hardier than their soft and blue cousins. Low moisture content and often a high salt content can make some cheeses keep for ages. (parmesan, pecorino) Figure the drier and saltier the cheese: the longer it will keep. Soft, relatively moist cheeses like gouda may only keep a couple of weeks.

When you see mold appear on a hard cheese, first cut off all visible mold. Discard moldy pieces. Wash your knife  and cutting board in hot, soapy water (If you don’t you’ll just spread mold to the underlying cheese. ). Then cut off another inch where the mold had been. And, yes, this will leave you with significantly less cheese. So, you can do the math: if your hunk of cheese is less than 2″, you won’t have anything left after trimming.  Hard cheeses are best kept wrapped in wax paper in the crisper drawer of your fridge.

Ice Cream:

Shelf life varies. Up to 2 months for commercial ice creams. Home made Ice Creams last less than a week.

Ice cream usually falls victim to ice crystals or freezer burn long before any bacteria have a chance to have at it. Ice cream has a high fat content, so just like butter and cream it is susceptible to picking up flavors. To best seal ice cream, cut a piece of plastic wrap and press it down to the surface of your ice cream. Reducing the air exposure will help keep your ice cream smooth  (not crystalline) for longer, it will also help keep prevent the transfer of unwanted flavors.

Eggs:

Shelf life varies based on processing and storage. Eggs bought at the grocery store can be good up to a month after the sell by date.

In my book, any ingredient that can make a souflee, an omelette and a creme brulee has more than a little magic to it. Even storing eggs has a few mysteries. Why, for instance, are eggs sold outside the US kept out, unrefrigerated? Turns out, in the US, eggs sold in grocery stores are all washed before they get to the store. This keeps the outside of the egg nice and clean (and with lower levels of bacteria), but it also damages the outside of the egg, making it more susceptible to spoiling in warm temperatures. Even after washing, the ideal holding temperature for eggs is slightly warmer than it is for dairy, so storage in the door of your refrigerator makes sense .

Like most vegetables and meat, eggs are likely to go bad from the outside. So even if you are buying washed eggs, it will be bacteria entering from the shell that will do the egg in. Even for washed eggs, the temperature storage is higher than for dairy. At the fat end of an egg, there is a little bubble of air. As the egg gets older, it gradually loses moisture. This bubble makes the float test for eggs work.  If an egg floats in water, it’s kaput. If it sinks it’s fresh. If it’s thinking about floating, you better use it quickly.  I like to mark a date on my eggs, so that I can ensure that I always use the oldest eggs I have first.

The huge contrast is once eggs are cracked, they have a very short shelf life. Those little shells are perfect containers, but once the eggs have been exposed to the bacteria in the air, and from cracking the shell, they need to be scrupulously refrigerated and used within a day or two. If you have extra egg whites or yolks, you can store the other portion of the egg in the freezer. Egg whites, particularly, will keep in the freezer almost indefinitely. Yolks, as all other fats, will eventually pick up that freezery taste, but you can get away with freezer storage for a little while.

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