GIFSQ Tools · Module 08 — Meat, Poultry, Fish & Seafood · Tool 141 of 500
Track the fall in meat pH after slaughter: enter pH at 45 minutes, 3 hours and 24 hours to get the total fall, the fall rate and a PSE / DFD classification.
Try sample values — fills the form with the worked example below.
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pH fall (45 min to 24 h)
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Fall rate (pH units / hour)
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Ultimate pH (24 h)
Equation: pH fall = pH at 45 minutes − pH at 24 hours. Fall rate = pH fall ÷ 23.25 hours (the time between the 45-minute and 24-hour readings). Ultimate pH is the 24-hour reading.
Method: Post-mortem pH fall in meat, measured by the pH electrode method AOAC 981.12. Normal pork and beef fall from about pH 6.4–6.8 at 45 minutes to an ultimate pH of 5.4–5.8 at 24 hours. A pH at 45 minutes under 5.8 points to PSE (pale, soft, exudative) meat; an ultimate pH over 6.0 points to DFD (dark, firm, dry) meat.
Assumptions: the three readings are from the same muscle and the same carcass; the pH meter was calibrated at the measurement temperature; the 45-minute reading was taken about 45 minutes after slaughter.
Limitations: the PSE and DFD bands are guide values, not specification limits — breeds, chilling rate and handling shift them; a single pH reading cannot diagnose PSE or DFD on its own; pH says nothing about microbial safety.
Rounding: pH fall and ultimate pH to 2 decimal places; fall rate to 2 decimal places; intermediates unrounded.
This is a calculation aid, not a laboratory report — confirm against your accredited method before citing a value.
Method: Post-mortem pH fall in meat, measured by the pH electrode method AOAC 981.12. Normal pork and beef fall from about pH 6.4–6.8 at 45 minutes to an ultimate pH of 5.4–5.8 at 24 hours. A pH at 45 minutes under 5.8 points to PSE (pale, soft, exudative) meat; an ultimate pH over 6.0 points to DFD (dark, firm, dry) meat.
Assumptions: the three readings are from the same muscle and the same carcass; the pH meter was calibrated at the measurement temperature; the 45-minute reading was taken about 45 minutes after slaughter.
Limitations: the PSE and DFD bands are guide values, not specification limits — breeds, chilling rate and handling shift them; a single pH reading cannot diagnose PSE or DFD on its own; pH says nothing about microbial safety.
Rounding: pH fall and ultimate pH to 2 decimal places; fall rate to 2 decimal places; intermediates unrounded.
This is a calculation aid, not a laboratory report — confirm against your accredited method before citing a value.
Worked example: pH 6.40 at 45 minutes, 6.00 at 3 hours and 5.55 at 24 hours. pH fall = 6.40 − 5.55 = 0.85; fall rate = 0.85 ÷ 23.25 = 0.04 pH units per hour; ultimate pH 5.55 — a normal fall.
Enter values above to see results.
Normal ultimate pH: 5.4–5.8. pH at 45 minutes under 5.8 suggests PSE; ultimate pH over 6.0 suggests DFD. Tool 141 of 500 — GIFSQ
