In order to conveniently and quickly detect the freshness of beef

oil compensation is carried out aiming at problems that the glass electrode is prone to be contaminated by oil

resulting in inaccurate pH measurement results.Firstly

the relationship between pH value and freshness of beef is analyzed theoretically.Secondly

the influence of oil on pH sensor measurement results is analyzed experimentally.A correlation analysis mathematical model of oil compensation is established according to the experimental results

and the measurement results are verified using the fuzzy analytic hierarchy process(F-AHP)sensory comprehensive evaluation.The experimental results show that the oil attaching to the glass electrode makes the pH measurement result less than the standard value

and the measurement error caused by the oil is as high as 6.9% at 25℃.A compensation mathematical model is established by correlation analysis

making the measurement error basically within the range of 0.03.The maximum storage time of fresh beef 5h after leaving the factory is 42h.The pH value of fresh meat decreases from 5.7 to 5.6 and then increases to 6.3 with time increasing

and the pH value of sub-fresh meat increases from 6.3 to 6.7 with time increasing

while that of rotten meat is above 6.7.Experiments and algorithms show that the established mathematical model is feasible and accurate for oil compensation.