Will slightly sour milk hurt a normal healthy person?

[No_umlaut_for_U]

@Shalmanese

There is NO relationship between smell and pathogenic microorganisms. Spoilage microorganisms and pathogenic microorganisms are two separate and distinct set of species. You can have milk that smells perfectly fine that cause harm and milk that is inedibly rotten that you could drink with abandon.

With proper pasteurization and avoidance of cross contamination, milk is acceptably safe for it’s entire usable lifespan. Throw milk out when it’s unpalatable but not because it will make you sick.

Whose milk actually sours today? I run into milk that has a revolting odor from pseudomonas and its evil little friends.

Agreeing with you. Milk is tested every which way. As long as it’s legally pasteurized, there are no surviving pathogens. (I suppose there are some spore-formers, possibly)

[Shalmanese]

@No_umlaut_for_U

Whose milk actually sours today? I run into milk that has a revolting odor from pseudomonas and its evil little friends.

Agreeing with you. Milk is tested every which way. As long as it’s legally pasteurized, there are no surviving pathogens. (I suppose there are some spore-formers, possibly)

Standard pasteurization doesn’t kill all bacteria. The standard HTST pasteurization achieves a log 5 reduction in bacteria (99.999% kill rate). For true shelf stable milk, you need to perform UHT pasteurization.

[puzzlegal]

@No_umlaut_for_U

Whose milk actually sours today?..

Maybe milk in Ireland? Last time I had sour milk there, it was actually sour, like vinegar. Not just sorta spoiled, like what happens to my milk.

[Melbourne]

Sourness in milk happens when Lacto-Bacillus convert the Lactose to acid and Carbon-Dioxide.

When you drink milk, you hope that, in the presence of Lactase (a digestive enzyme) the Lactose will spontaneously convert into galactose and glucose.

If the milk already contains a large Lacto-Bacillus population, and has not yet gone completely sour, you sometimes find that the Lacto-Bacilli are digesting the milk faster than you are, and that you get…

Gas, bloating, and the runs…

This will not “hurt a healthy person”, but it will “give you a tummy ache”

If all the sugar has been converted to acid, you won’t get Gas or bloating, but you may get the runs: I find that if I have a really unbalanced ph meal, (like only tomatoes) it tends to go straight through me.

[Learjeff]

“Unspoiled milk is generally safe.” This is a valid premise.
“Spoiled milk is generally dangerous.” This is the assumption implicit in the OP, but isn’t a valid conclusion. “Spoiled milk can’t be assumed to be safe” is a better corollary.

@Johanna

There’s a significant difference between properly soured milk—e.g. buttermilk, yogurt, clabber, sour cream, crème fraîche, kefir—and spoiled milk. The former is good. The latter is not. When it goes off after its expiration date in your fridge, there’s nothing you can do but throw it away. It tastes like ass and would probably make you sick. Sorry. I guess it depends on the exact type of culture you have going there. They’re not all the same. Some are desirable and some completely ruin the milk.

Bingo.

The poll makes no sense because it has an invalid assumption, that “more spoiled” is “worse for you”. No, a better statement is, the longer it goes, the more cultures you’ll get in it. Cultures of what? Lactogens. As it turns out (as I learned in BioEng 495), a lot of pathogens are lactogens, for reasons that made sense then but I don’t recall. Well, all those lovely things mentioned above are lactogens and safe. But when you let milk go bad, and it’s been open to the air a few times, you’re playing lactogen russian roulette.

As it turns out, it’s russian roulette with a lot of chambers, way more than six, so your odds of getting very nastily sick are pretty low each time you do it, but a habit of it is not good, and it’s bad public health policy to encourage people to drink sour milk.

@Amateur_Barbarian

I’d be interested in an authoritative answer about when “sour” milk is actually unsafe to consume.

See above and below: there isn’t really a sensible answer to this question, because the question doesn’t quite acknowledge the facts. The taste is related to particular bacteria, but it’s other bacteria that we worry about. You could do a probability analysis and give an authoritative statistical answer. What would your limit for probability of potentially lethal bacteria be?

@njtt

I have often drunk milk that is a bit sour, and even, on occasion, milk that has begun to curdle a bit. The curds will usually sink, so sometimes I don’t even know it curdling until I have drunk a bit (and it sometimes does not seem more than slightly sour, even when there are curd down there). It doesn’t taste very good, bit I have never never noticed any sort of digestive problems caused by any of this. Sometimes, if the end of a bottle is souring, I will mix small amounts of it into my fresh milk, just to use it up.

Yup, and I’ve eaten a lot of very rare hamburger, and it hasn’t gotten me sick yet. That doesn’t mean it’s a good idea.

@dracoi

Food poisoning is all a matter of how much is in there and of what type. At best, you’ll get an answer like “x% of people got sick under the described handling methods.” We don’t actually know the details of how the OP’s milk was handled, though.

Many of the things considered unsafe in modern food handling are mitigating very small risks. After all, if even 1% of people got food poisoning, we’d consider that unacceptable. From a manufacturer’s standpoint, that’s hundreds of people a day getting sick. On the other hand, if you’re an individual weighing the odds of surviving that last bit of sour milk, 99% chance of no problem seems like a pretty safe bet.

Bingo. This points out the difference between personal risk and public policy. I do things where there’s a 0.01% chance of something bad happening, but I don’t do them thousands of times, and if I were in charge of public policy, I’d select policy to discourage them.

@Shalmanese

There is NO relationship between smell and pathogenic microorganisms. Spoilage microorganisms and pathogenic microorganisms are two separate and distinct set of species. You can have milk that smells perfectly fine that cause harm and milk that is inedibly rotten that you could drink with abandon.

Bingo … at best there’s some statistical correlation between spoilage and danger. The better correlation is that since spoilage is pretty much guaranteed after a given time, if it’s not spoiled yet, then it’s also very likely to be safe. The converse isn’t justified.

With proper pasteurization and avoidance of cross contamination, milk is acceptably safe for it’s entire usable lifespan. Throw milk out when it’s unpalatable but not because it will make you sick.

Well, it definitely could make you sick. Even with perfect pasteurization (which we have pretty close to these days, with irradiation, yielding long shelf lives before opening), once the container is open, bets are off: anything could get in there.

[Shalmanese]

@Learjeff

Well, it definitely could make you sick. Even with perfect pasteurization (which we have pretty close to these days, with irradiation, yielding long shelf lives before opening), once the container is open, bets are off: anything could get in there.

Milk is not irradiated in the US due to fears of scary, evil radiation.

[salinqmind]

I always put a drop of milk in my morning coffee, like 2 tablespoons worth if I measured it. If my coffee is full of tiny white flecks of souring milk, I’ll drink it anyway! Hasn’t inconvenienced me yet. The carton of souring milk goes out, though.

[Learjeff]

@Shalmanese

Milk is not irradiated in the US due to fears of scary, evil radiation.

Thanks, ignorance fought!

[Reisenweber]

Raised in a country without refrigeration, chunky milk and green cheese was considered normal. Nobody got sick, lived into their 80’s and 90’s in their own home without developing Alzeimers.

[Chronos]

Milk will eventually go bad enough to be a non-negligible health risk. However, it will also eventually go bad enough that it tastes really bad, and it’ll almost always do that before it becomes a health risk. I won’t drink milk that tastes bad, but that’s not because I’m afraid that it’ll make me sick; it’s because it tastes bad.

[rowrrbazzle]

My grandfather occasionally drank spoiled milk with cinnamon sprinkled on top. I never tasted it, but my older brother developed the taste. (For comparison, my brother also liked dark chocolate, but I don’t.)

[nachtmusick]

Of all of the myriad things that have sickened me, milk is not one of them. When milk is bad, you’ll know it.

[JKellyMap]

@Reisenweber

Raised in a country without refrigeration, chunky milk and green cheese was considered normal. Nobody got sick, lived into their 80’s and 90’s in their own home without developing Alzeimers.

Where, may I ask?

[Gatopescado]

Well, by now, it certainly bad!