Dr. Brian Nummer PhD

FOOD-SAFETY.GURU

Page: Develop your acid food products with safe pH levels!

pH-buffer2 GUIDANCE: The most important factor is that the pH of your product absolutely MUST be pH ≤ 4.6  AND most published scientific data on thermal processing essentially require one of the the following:

  1. pH 4.2 to 4.5 require a thermal process approximately 200°F for 30 minutes (typically these foods are cooked in batch for this time and then bottled as in item number 2.).
  2. pH ≤ 4.2 requires a thermal process of approximately 180°F for 1 minute
  3. pH ≤ 3.8 with 0-20% mustard flour and ≥1.0% acetic acid may be cold filled provided its held at room temperature for 7 days before sale (mustard only)
  4. pH ≤ 3.8 with 1.5% acetic acid AND 0.1% sodium benzoate may be cold filled provided its held at room temperature for 7 days before sale
  5. pH ≤ 3.3 may be cold filled provided its held at room temperature for 7 days before sale
  6. other scientific references may exist; e.g. mustards and mayonnaise-based foods.

Note a few limitations on the scientific references mentioned above:

  • You cant cold fill anything above pH 3.8 regardless of the formulation.
  • Expect a higher and longer thermal process for foods between pH 4.2 and 4.5.
  • There are currently no scientific studies permitting canning foods above pH 4.5 without using a pressure or low acid thermal process (temperatures approx 230-240°F).
  • When cold filling you MUST address spoilage.  You should either prove via lab studies spoilage doesn’t occur or use preservatives.


Q: What about sugar syrups with a pH above 4.5?

A: Sugar syrups can be thermally processed without the need for a pressure process only if the water activity (Aw) is ≤ 0.85.  Water activity is measured using a water activity meter that typically costs $1500 to $4000.  A testing lab can provide this information for a fee.  Never reduce or remove the sugar in these types of products or the safety factor inhibiting botulism will also be removed.

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