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DomDeFranco

DomDeFranco

I've been looking into water activity (AW) and shelf life and came across some interesting formulas for estimating shelf life from the water activity of an item.

 

First a few provisos:

  1. This formula was originally developed for baked goods, in particular cakes.
  2. The formula has only been validated for AW's between 0.74-0.90
  3. The formula assumes that the items will be stored at a constant temperature. The formula below is for 21 Degrees Celsius.
  4. The formula assumes that the AW of the item does not change while in storage. 
  5. When we're talking about shelf life here, they specify Mould Free Shelf Life (MFSL). Obviously whether the product has mould or not is certainly not the only factor that would affect it's quality.

So with that all being said, I thought the results were interesting and in some cases very different from the previous examples given in the thread from Melissa Coppel and Wybauw.

 

Stored at 21 Degrees Celsius

Log10 (MFSL, days at 21°C) =7.91 - (0.081 x AW)

AW     MFSL (Days)     MFSL (Weeks)

74          82                            10.8

75          68                            9.8

76          57                            8.1

77          47                            6.7

78          39                            5.6

79          32                            4.6

80          27                            3.8

81          22                            3.2

82          19                            2.6

83          15                            2.2

84          13                            1.8

85          11                             1.5

86           9                             1.3

87           7                              1.0

88           6                              0.9

89           5                              0.7

90           4                              0.6

 

I came across it in chapter 17 on water activity and shelf life in Confectionary & Chocolate Engineering. I then found the same formula again in Bakery Food Manufacture & Quality which cited original work on this going back to the 60s which was then "robustly" validated in papers published in the 90s. A particular paper that gets cited a bit but i can't actually find seems to be where the original formulas come from. Couvain, S. P., and D. A. L. Deiler. "Equilibrium relative humidity and the shelf life of cakes." FMBRA Report 50 (1992).  

 

Obviously the best way to assess shelf life is to actually test it, but I thought it was interesting and useful so thought I'd share it. There is a webpage that has the calculator where you can select 21 or 27 Degrees C and enter your AW. It will then give you an estimate for the MFSL. https://www.dairyscience.info/newCalculators/mould.asp

 

 

DomDeFranco

DomDeFranco

I've been looking into water activity (AW) and shelf life and came across some interesting formulas for estimating shelf life from the water activity of an item.

 

First a few provisos:

  1. This formula was originally developed for baked goods, in particular cakes.
  2. The formula has only been validated for AW's between 0.74-0.90
  3. The formula assumes that the items will be stored at a constant temperature. The formula below is for 21 Degrees Celsius.
  4. The formula assumes that the AW of the item does not change while in storage. 
  5. When we're talking about shelf life here, they specify Mould Free Shelf Life (MFSL). Obviously whether the product has mould or not is certainly not the only factor that would affect it's quality.

So with that all being said, I thought the results were interesting and in some cases very different from the previous examples given in the thread from Melissa Coppel and Wybauw.

 

Stored at 21 Degrees Celsius

Log10 (MFSL, days at 21°C) =7.91 - (0.081 x AW)

AW     MFSL (Days)     MFSL (Weeks)

74          82                            10.8

75          68                            9.8

76          57                            8.1

77          47                            6.7

78          39                            5.6

79          32                            4.6

80          27                            3.8

81          22                            3.2

82          19                            2.6

83          15                            2.2

84          13                            1.8

85          11                             1.5

86           9                             1.3

87           7                              1.0

88           6                              0.9

89           5                              0.7

90           4                              0.6

 

I came across it in chapter 17 on water activity and shelf life in Confectionary & Chocolate Engineering. I then found the same formula again in Bakery Food Manufacture & Quality which cited original work on this going back to the 60s which was then "robustly" validated in a papers published in the 90s. A particular paper that gets cited a bit but i can't actually find seems to be where the original formulas come from. Couvain, S. P., and D. A. L. Deiler. "Equilibrium relative humidity and the shelf life of cakes." FMBRA Report 50 (1992).  

 

Obviously the best way to assess shelf life is to actually test it, but I thought it was interesting and useful so thought I'd share it. There is a webpage that has the calculator where you can select 21 or 27 Degrees C and enter your AW. It will then give you an estimate for the MFSL. https://www.dairyscience.info/newCalculators/mould.asp

 

 

DomDeFranco

DomDeFranco

I've been looking into water activity (AW) and shelf life and came across some interesting formulas for estimating shelf life from the water activity of an item.

 

First a few provisos:

  1. This formula was originally developed for baked goods, in particular cakes.
  2. The formula has only been validated for AW's between 0.74-0.90
  3. The formula assumes that the items will be stored at a constant temperature. The formula below is for 21 Degrees Celsius.
  4. The formula assumes that the AW of the item does not change while in storage. 
  5. When we're talking about shelf life here, they specify Mould Free Shelf Life (MFSL). Obviously whether the product has mould or not is certainly not the only factor that would affect it's quality.

So with that all being said, I thought the results were interesting and in some cases very different from the previous examples given in the thread form Melissa Coppel and Wybauw.

 

Stored at 21 Degrees Celsius

Log10 (MFSL, days at 21°C) =7.91 - (0.081 x AW)

AW     MFSL (Days)     MFSL (Weeks)

74          82                            10.8

75          68                            9.8

76          57                            8.1

77          47                            6.7

78          39                            5.6

79          32                            4.6

80          27                            3.8

81          22                            3.2

82          19                            2.6

83          15                            2.2

84          13                            1.8

85          11                             1.5

86           9                             1.3

87           7                              1.0

88           6                              0.9

89           5                              0.7

90           4                              0.6

 

I came across it in chapter 17 on water activity and shelf life in Confectionary & Chocolate Engineering. I then found the same formula again in Bakery Food Manufacture & Quality which cited original work on this going back to the 60s which was then "robustly" validated in a papers published in the 90s. A particular paper that gets cited a bit but i can't actually find seems to be where the original formulas come from. Couvain, S. P., and D. A. L. Deiler. "Equilibrium relative humidity and the shelf life of cakes." FMBRA Report 50 (1992).  

 

Obviously the best way to assess shelf life is to actually test it, but I thought it was interesting and useful so thought I'd share it. There is a webpage that has the calculator where you can select 21 or 27 Degrees C and enter your AW. It will then give you an estimate for the MFSL. https://www.dairyscience.info/newCalculators/mould.asp

 

 

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