Effect of whey protein isolate on keeping quality and shelf life of minced meat

Minced meat is a widely consumed and popular meat product, known for its high nutritional value. However, it is prone to contamination by a multitude of microorganisms. Therefore, the aim of this work was to improve the keeping quality and safety of chilled minced meat by using whey protein isolate (WPI) at different concentrations 1, 3, and 5% to assess their effect on the sensory attributes, chemical parameters (pH, total volatile nitrogen, thiobarbituric acid and amino acid content), and bacteriological status including total bacterial count, enterobacteriaceae count, coliform count, and staphylococcal count in minced meat stored at 4°C for 12 days, in addition, detection of some staphylococcal enterotoxins. The results showed that adding different concentrations of WPI improved the treated minced meat samples sensory qualities when compared to the control samples. WPI also improved the chilled minced meat's chemical properties by lowering pH, total volatile nitrogen, and thiobarbituric acid values while raising the amount of essential amino acids when compared to the control group. Furthermore, WPI significantly reduced the bacterial counts. Among the different concentrations tested, 5% of WPI exhibited the most significant improvement in terms of sensory, chemical, and bacterial quality, surpassing the effects observed with 1% and 3% concentrations. Incidence of Staph. aureus in the control group and the minced meat treated with 1% and 3% WPI was 60%, 20%, and 20% respectively. However, no Staph. aureus was isolated from the treated samples with 5% WPI.  In control samples, enterotoxins A, A+C, and A+D were detected in 20% of each of the examined samples, respectively; enterotoxin D was detected in 20% of sample treated with 3% WPI; enterotoxin A+C was detected in 20% of sample treated with 1% WPI. The study concluded that utilizing WPI as a natural antioxidant and antibacterial preservative for refrigerated minced meat can extend its shelf life up to 12 days, in contrast to the control group, which spoiled completely within 6 days of chilled storage.