# Can milk spoil without a detectable smell? **URL:** \ **Category:** Factual Questions\ **Created:** [October 23, 2008, 1:53pm UTC](https://boards.straightdope.com/t/can-milk-spoil-without-a-detectable-smell/469206 "2008-10-23T13:53:02Z")\ **Posts on this page:** 8\ **Page:** 1
**Author:** ![robby](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/robby/32/11048_2.png) [@robby](https://boards.straightdope.com/u/robby)\ **Post date:** [October 23, 2008, 1:53pm UTC](https://boards.straightdope.com/t/can-milk-spoil-without-a-detectable-smell/469206/1 "2008-10-23T13:53:02Z")
Years ago, I was convinced that I suffered food poisoning from spoiled milk. At a Scout camp when I was a kid, a pallet of of individual half-pints of milk was allowed to sit out unrefrigerated for several hours until the milk had completely warmed up to room temperature. Instead of disposing of them, they were instead put back in the refrigerator. When the milk was put out for distribution again the next day, it had no detectable bad taste or smell. That being the case, could it have sickened me? (Because after drinking the milk, I got violently ill and threw up harder than I ever had in my life.) People who I related the story to have told me that my story is impossible. Spoiled milk, I am told, will always have a bad taste and/or smell. One person has told me that you can’t get sick from old or spoiled milk if you have a nose. Is this true? ---
**Author:** ![Szlater](https://avatars.discourse-cdn.com/v4/letter/s/90ced4/32.png) [@Szlater](https://boards.straightdope.com/u/Szlater)\ **Post date:** [October 23, 2008, 2:27pm UTC](https://boards.straightdope.com/t/can-milk-spoil-without-a-detectable-smell/469206/2 "2008-10-23T14:27:28Z")
Sounds like _Bacillus cereus_ poisoning, what with the rapid onset vomiting. It has been found in pasteurised milk along with lots of other organisms. Don’t know about the smell of _B. cereus_ though. Leaving food out to warm up is extremely bad food hygiene practice. Here’s a study of organisms in raw and pasteurised milk. > [@Appl Bacteriol. 1993 Jul ;75 (1):25-34 8365951](#): > > Eighty-one bacterial strains isolated from refrigerated raw milk, 124 from pasteurized milk and cream stored at 5 degrees C and 7 degrees C, and 19 type and reference strains of Pseudomonas spp. and Bacillus spp. were characterized by numerical phenotypic analysis. Data were processed with simple matching (SSM) and Jaccard (SJ) coefficients, and UPGMA clustering. Fourteen clusters of Gram-negative bacteria were formed at SJ = 79% (SSM = 90%). Raw milk was exclusively spoilt by Gram-negative bacteria, the majority of which were Pseudomonas fluorescens biovar I, Ps. fragi, Ps. lundensis and Ps. fluorescens biovar III. Minor groups in raw milk included Enterobacteriaceae spp. and Acinetobacter spp. Pasteurized milk was spoilt by essentially the same Gram-negative organisms in 65% (5 degrees C) and 50% (7 degrees C) of the cases. The phenotypic characteristics of Gram-negative bacteria are given. Bacillus polymyxa (both temperatures) and B. cereus (only at 7 degrees C) were responsible for 77% of samples spoiled by the Gram-positive organisms. Minor milk spoilage groups included other Bacillus spp. and lactic acid bacteria. All Bacillus spp. grew fermentatively in milk, and most strains denitrified. It is suggested that: (i) industrial recontamination tests of pasteurized milk are directed against Pseudomonas; (ii) milk is stored at 5 degrees C or lower to avoid growth of B. cereus; and (iii) the significance of gas-producing and nitrate/nitrite-reducing Bacillus strains is recognized in cheese production. ---
**Author:** ![Mr\_Buttons](https://avatars.discourse-cdn.com/v4/letter/m/a6a055/32.png) [@Mr\_Buttons](https://boards.straightdope.com/u/Mr_Buttons)\ **Post date:** [October 23, 2008, 2:54pm UTC](https://boards.straightdope.com/t/can-milk-spoil-without-a-detectable-smell/469206/3 "2008-10-23T14:54:26Z")
Entirely anecdotal evidence: Monday night i had some cocoa pebbles and milk. The milk was ‘Sell by 10/23’, which would be today. I smelled it just to be sure, and it smelled fine. About thirty minutes later the churning and cramps started to come on. Spent the subsequent 2 hours praying to the porcelain gods. So I vote ‘yes’ that you can get sick from milk that hasn’t gotten a bad smell/taste. reflecting on it the following day, i realized the milk had been stored along our fridge door, which is the warmest part of the fridge. I’m reasonably sure this is why it went bad before the “sell by” date ---
**Author:** ![masterofnone](https://avatars.discourse-cdn.com/v4/letter/m/4bbf92/32.png) [@masterofnone](https://boards.straightdope.com/u/masterofnone)\ **Post date:** [October 23, 2008, 3:05pm UTC](https://boards.straightdope.com/t/can-milk-spoil-without-a-detectable-smell/469206/4 "2008-10-23T15:05:35Z")
> [@Szlater](#): > > Don’t know about the smell of _B. cereus_ though. _B. cereus_ doesn’t have a particularly strong smell. I work with it in the lab, and a pure culture has a slightly earthy smell that would easily be masked by milk. Of course, the odor may depend on the food source, but we grow it on tryptic soy agar, which contains a digest of casein, so I suspect it’s similar. Lots of bugs can cause illness long before they have produced enough waste products to produce a noticable smell. ---
**Author:** ![robby](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/robby/32/11048_2.png) [@robby](https://boards.straightdope.com/u/robby)\ **Post date:** [October 23, 2008, 3:46pm UTC](https://boards.straightdope.com/t/can-milk-spoil-without-a-detectable-smell/469206/5 "2008-10-23T15:46:02Z")
> [@masterofnone](#): > > …Lots of bugs can cause illness long before they have produced enough waste products to produce a noticable smell. That’s always been my understanding as well. But people are telling me that it works differently for milk. (Personally, I think they’re wrong, and that you can be sickened by milk even without a noticeable smell.) ---
**Author:** ![masterofnone](https://avatars.discourse-cdn.com/v4/letter/m/4bbf92/32.png) [@masterofnone](https://boards.straightdope.com/u/masterofnone)\ **Post date:** [October 23, 2008, 4:14pm UTC](https://boards.straightdope.com/t/can-milk-spoil-without-a-detectable-smell/469206/6 "2008-10-23T16:14:00Z")
> [@robby](#): > > That’s always been my understanding as well. But people are telling me that it works differently for milk. (Personally, I think they’re wrong, and that you can be sickened by milk even without a noticeable smell.) I have no idea why people would think such a thing - perhaps it is because of the mild odor of milk not being able to mask much? Whatever their reasoning - they’re wrong. Milk is an excellent growth media, and it takes very low numbers of bacteria to cause illness (depending on species and immune system health). I’d reccomend staying away from dairy products at their houses or at least BYOM. ---
**Author:** ![robby](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/robby/32/11048_2.png) [@robby](https://boards.straightdope.com/u/robby)\ **Post date:** [October 23, 2008, 5:16pm UTC](https://boards.straightdope.com/t/can-milk-spoil-without-a-detectable-smell/469206/7 "2008-10-23T17:16:38Z")
Thanks for the replies! ---
**Author:** ![puppygod](https://avatars.discourse-cdn.com/v4/letter/p/ce7236/32.png) [@puppygod](https://boards.straightdope.com/u/puppygod)\ **Post date:** [October 23, 2008, 5:23pm UTC](https://boards.straightdope.com/t/can-milk-spoil-without-a-detectable-smell/469206/8 "2008-10-23T17:23:10Z")
> [@masterofnone](#): > > I have no idea why people would think such a thing - perhaps it is because of the mild odor of milk not being able to mask much? Whatever their reasoning - they’re wrong. Milk is an excellent growth media, and it takes very low numbers of bacteria to cause illness (depending on species and immune system health). My guess is that they are under (mistaken) impression that there is only one way for milk to spoil (via activity of lactic acid bacteria) and don’t realize that there are much more bugs that can cause your intestines to go south.