# Is jam safe three days past its due date? (Need answer fast?) **URL:** \ **Category:** Factual Questions\ **Created:** [April 29, 2012, 6:03pm UTC](https://boards.straightdope.com/t/is-jam-safe-three-days-past-its-due-date-need-answer-fast/620340 "2012-04-29T18:03:33Z")\ **Posts on this page:** 13\ **Page:** 2
**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\ **Post date:** [April 30, 2012, 7:04am UTC](https://boards.straightdope.com/t/is-jam-safe-three-days-past-its-due-date-need-answer-fast/620340/21 "2012-04-30T07:04:49Z")
> [@lazybratsche](#): > > With jam or anything else that’s soft, there’s a lot more mold than just the visible stuff. That fuzzy green/black/white mold is only the fruiting body of a much mycelium, with “roots” that go far into the food. > > In the lab, I commonly encounter molds as contaminants in agar petri dishes. A tiny, barely-visible spot on the surface might have mycelia extending 1 cm deep (visible under a microscope). And a 1 cm diameter visible colony will have mycelia throughout an entire 10 cm petri dish. Agar is pretty bland stuff compared to jam though - I’d be really interested to know if mould mycelia can penetrate like than into such a strongly-sugary substrate as tradtitional jam - wouldn’t the mycelia just get dehydrated by osmosis? ---
**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\ **Post date:** [April 30, 2012, 7:11am UTC](https://boards.straightdope.com/t/is-jam-safe-three-days-past-its-due-date-need-answer-fast/620340/22 "2012-04-30T07:11:08Z")
> [@casdave](#): > > It depends upon the jam. > > Most jams are made with up to 45% fruit and the remainder is sugar and setting agents - this is the stuff that will be fine, in the UK it will have a ‘best before’ date which is an indication that the contents may have compromised quality. Such foods are unlikely to cause food poisoning. > > However… > > There is a recent trend for ‘extra’ jams, reduced sugar jams and of course diabetic jam. These may have fruit content up to 65% - any more tends not to set at all - they are definitely more intense tasting and generally significantly more expensive. > > Manufacturers instructions tend to be along the lines of ‘Refrigerate once opened and consume within 6 weeks’. > > This can be confusing since it may have a ‘best before’ referring to the safety of the jam prior to being opened, but one the lid is off it effectively becomes ‘use-by’ food whose date should not be exceeded. > > In other words, you need to read the label, under 45% fruit and you will be fine, over 45% and you may need to put it in the fridge - depends upon other preservatives that it may contain. In the UK, at least (and assuming the manufacturers are playing by the rules) it should be simpler than that - if it’s labelled ‘jam’, it has to be at least 60% sugar by weight ([cite](http://www.food.gov.uk/multimedia/pdfs/publication/jamfactsheet0210.pdf)). If it contains less than that, it’ll be labelled ‘preserve’, ‘conserve’, ‘compote’ or some such. ---
**Author:** ![sandra\_nz](https://avatars.discourse-cdn.com/v4/letter/s/eada6e/32.png) [@sandra\_nz](https://boards.straightdope.com/u/sandra_nz)\ **Post date:** [April 30, 2012, 7:35am UTC](https://boards.straightdope.com/t/is-jam-safe-three-days-past-its-due-date-need-answer-fast/620340/23 "2012-04-30T07:35:43Z")
People are talking about two different labels here. **Best by** … is different to **Use before** … Best by \ just means that. The food will be at it’s best if consumed before \. That doesn’t mean it suddenly transforms overnight into a slavering mould monster intent on poisoning your intestines. It just means that its flavour/consistency/etc will be optimal before \. ---
**Author:** ![wheresmymind](https://avatars.discourse-cdn.com/v4/letter/w/91b2a8/32.png) [@wheresmymind](https://boards.straightdope.com/u/wheresmymind)\ **Post date:** [April 30, 2012, 7:57am UTC](https://boards.straightdope.com/t/is-jam-safe-three-days-past-its-due-date-need-answer-fast/620340/24 "2012-04-30T07:57:45Z")
You keep jam in the fridge? Seriously, there’s a jar of jam in my cupboard that I opened well over a year ago. Completely unrefrigerated. Had some last week, it was fine. Attached to your head you’ll find a “nose” and a “tongue.” They’re there (among other reasons) to answer questions like these for you. And before anyone asks, yes, you can eat pizza the day after, even if it’s been sitting out on the counter. ---
**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\ **Post date:** [April 30, 2012, 8:01am UTC](https://boards.straightdope.com/t/is-jam-safe-three-days-past-its-due-date-need-answer-fast/620340/25 "2012-04-30T08:01:27Z")
> [@wheresmymind](#): > > Attached to your head you’ll find a “nose” and a “tongue.” They’re there (among other reasons) to answer questions like these for you. Cute, but smell and taste are not necessarily reliable indicators of food safety (present thread notwithstanding). If they were, the phenomenon we call ‘food poisoning’ would be a good deal less common. ---
**Author:** ![casdave](https://avatars.discourse-cdn.com/v4/letter/c/c6cbf5/32.png) [@casdave](https://boards.straightdope.com/u/casdave)\ **Post date:** [April 30, 2012, 11:04am UTC](https://boards.straightdope.com/t/is-jam-safe-three-days-past-its-due-date-need-answer-fast/620340/26 "2012-04-30T11:04:46Z")
**Mangetout** That’s pretty much what I said, OK I was 5% out on the fruit content. Read the manufacturers label is still the best advice, there are peculiarities that can catch you out. As for those who store stuff in ‘the way they have always done and its never caused them any harm’ - well sure we often get away with it but it does not mean that its a safe thing to do. ---
**Author:** ![Imago](https://avatars.discourse-cdn.com/v4/letter/i/85e7bf/32.png) [@Imago](https://boards.straightdope.com/u/Imago)\ **Post date:** [April 30, 2012, 11:24am UTC](https://boards.straightdope.com/t/is-jam-safe-three-days-past-its-due-date-need-answer-fast/620340/27 "2012-04-30T11:24:08Z")
> [@sandra\_nz](#): > > People are talking about two different labels here. **Best by** … is different to **Use before** … > > Best by \ just means that. The food will be at it’s best if consumed before \. That doesn’t mean it suddenly transforms overnight into a slavering mould monster intent on poisoning your intestines. It just means that its flavour/consistency/etc will be optimal before \. I’ve only ever seen one date on everything. Maybe it’s different in the US. ---
**Author:** ![kayaker](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/kayaker/32/441_2.png) [@kayaker](https://boards.straightdope.com/u/kayaker)\ **Post date:** [April 30, 2012, 11:24am UTC](https://boards.straightdope.com/t/is-jam-safe-three-days-past-its-due-date-need-answer-fast/620340/28 "2012-04-30T11:24:40Z")
Are you sure it’s jam?:dubious: Must be jelly, cause jam don’t Shake like that. ---
**Author:** ![Francis\_Vaughan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/francis_vaughan/32/3093_2.png) [@Francis\_Vaughan](https://boards.straightdope.com/u/Francis_Vaughan)\ **Post date:** [April 30, 2012, 11:27am UTC](https://boards.straightdope.com/t/is-jam-safe-three-days-past-its-due-date-need-answer-fast/620340/29 "2012-04-30T11:27:41Z")
Just to add, I discovered many years ago that not only are proper jams essentially unkillable, some actual age. My mother used to make plum jam and apricot jam. (As kids our job was to stir the cauldron, I used to think it was a pretty fair deal.) These were serious jams. A ten year old jar of the plum jam recovered from the cellar was found to have aged much like you might hope a fine wine might. The colour was muted and a bit brown, but the flavour was something quite different and very pleasant. I could only relate it to much the same processes as a wine, or perhaps a better analogue - a port - ageing. I rather wish I had some left. ---
**Author:** ![sandra\_nz](https://avatars.discourse-cdn.com/v4/letter/s/eada6e/32.png) [@sandra\_nz](https://boards.straightdope.com/u/sandra_nz)\ **Post date:** [April 30, 2012, 11:31am UTC](https://boards.straightdope.com/t/is-jam-safe-three-days-past-its-due-date-need-answer-fast/620340/30 "2012-04-30T11:31:32Z")
Looks like Canada does it slightly differently, with a Durable Life (has a Best BeforeDate) and Expiration Dates (which I guess is the equivalent of the UK Use By). [Date Labelling on Pre-packaged Foods - Canadian Food Inspection Agency](http://www.inspection.gc.ca/food/consumer-centre/food-safety-tips/labelling-food-packaging-and-storage/date/eng/1332357469487/1332357545633) ---
**Author:** ![Glottis](https://avatars.discourse-cdn.com/v4/letter/g/6a8cbe/32.png) [@Glottis](https://boards.straightdope.com/u/Glottis)\ **Post date:** [April 30, 2012, 11:42am UTC](https://boards.straightdope.com/t/is-jam-safe-three-days-past-its-due-date-need-answer-fast/620340/31 "2012-04-30T11:42:51Z")
> [@Mangetout](#): > > > [@Imago](#): > > > > but I did have to stir it violently with a butter knife because it was all in one piece in the jar. > > This sounds like a description of jam. It sounds like a description of jam given by someone who has never encountered jam before. Weird. Trying to unjam it perhaps? ---
**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\ **Post date:** [April 30, 2012, 12:04pm UTC](https://boards.straightdope.com/t/is-jam-safe-three-days-past-its-due-date-need-answer-fast/620340/32 "2012-04-30T12:04:42Z")
> [@casdave](#): > > **Mangetout** > > That’s pretty much what I said, OK I was 5% out on the fruit content. Agreed - I wasn’t nitpicking you - only expanding that for certain categories, the front label should be definitive. ---
**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\ **Post date:** [April 30, 2012, 12:08pm UTC](https://boards.straightdope.com/t/is-jam-safe-three-days-past-its-due-date-need-answer-fast/620340/33 "2012-04-30T12:08:25Z")
> [@Francis\_Vaughan](#): > > Just to add, I discovered many years ago that not only are proper jams essentially unkillable, some actual age. My mother used to make plum jam and apricot jam. (As kids our job was to stir the cauldron, I used to think it was a pretty fair deal.) These were serious jams. A ten year old jar of the plum jam recovered from the cellar was found to have aged much like you might hope a fine wine might. The colour was muted and a bit brown, but the flavour was something quite different and very pleasant. I could only relate it to much the same processes as a wine, or perhaps a better analogue - a port - ageing. I rather wish I had some left. A really old jam (and especially plum, IMO) can be quite special, and yes - I think it’s probably analogous to ageing of wine/port - some sort of enzymatic process, I expect. [Previous page](https://boards.straightdope.com/t/is-jam-safe-three-days-past-its-due-date-need-answer-fast/620340.md?page=1)