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This commercial peach jam does NOT contain any preservatives.
Room temperature is 20 C.

It is written on the bottle that it should be refrigerated after opening since it doesn't contain any preservatives.

For how long can I keep it in the cupboard after opening?

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    What's the issue with keeping it in the fridge after you open it?
    – Kareen
    Commented Feb 21, 2013 at 6:31
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    Not everyone with internet access has a fridge. Commented Feb 22, 2013 at 4:15
  • You ask some very interesting questions Anisha. Commented Mar 6, 2013 at 5:08

2 Answers 2

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There'll be a lot of variation depending on temperature, humidity, the exact nature of the jam, and pure dumb luck, but I wouldn't be surprised if it started growing mold within a week, if not within a day or two. When things say to refrigerate after opening, they tend to mean it.

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  • but I thought sugar will prevent the bacteria? Commented Feb 21, 2013 at 6:54
  • @AnishaKaul Mold isn't bacteria.
    – Cascabel
    Commented Feb 21, 2013 at 7:02
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    @AnishaKaul And to elaborate a bit more, sugar is indeed a preservative, but it's not magic, especially when there's plenty of moisture present. This is why when you store jam and other preserves you have to process it in boiling water to kill whatever might be in there; some things will still grow in there. Once you've opened it back up, you allow recontamination and provide more air, so things are even more able to grow.
    – Cascabel
    Commented Feb 21, 2013 at 7:15
  • 20C is 68 degrees F. That is a pretty much perfect temperature for fermentation to occur, and about the perfect temperature for mold to start growing. You're basically making a petri dish. Can you do it? Yes, but I'd be really, really careful. Let your sense of smell and your eyes guide you. If it smells bacterial or moldy, throw it.
    – Matthew
    Commented Feb 21, 2013 at 15:45
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Once the jar is opened, it may get contaminated, by anything suspended in the air, by cross-contamination ...etc.

  • sunlight
  • air
  • heat
  • moisture
  • nutrients (your jam)

All of these will provide good conditions for cell culture (e.g. molds). Make sure you keep it sealed properly and stashed away in a dry cool place. Because there are no preservatives, there is nothing to prevent or stall those unwanted elements from growing. Use it within a few days.

If you ever had fruits / bread grow mold at your place, that should give you an idea on how long you can expect to keep it once opened before it goes bad.

E.g. black bread mold loves temperatures 15 - 30 C.

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