Changes in physicochemical properties and bacterial communities in aged Korean native cattle beef during cold storage

Area of Science:

• Food Science
• Microbiology
• Biochemistry

Background:

• Aged beef quality is influenced by storage conditions, affecting its physicochemical and microbial properties.
• Understanding these changes is crucial for the beef industry and consumer acceptance.

Purpose of the Study:

• To evaluate microbial, volatile compound, and amino acid changes in raw, dry-, and wet-aged beef during cold storage.
• To assess the degree of putrefaction using volatile basic nitrogen (VBN) values.

Main Methods:

• Raw, dry-, and wet-aged beef samples were stored at 4°C for 21 days.
• Measurements included pH, volatile basic nitrogen (VBN) levels, microbial counts (psychrophilic, lactic acid, mesophilic bacteria), volatile compounds, and amino acids.

Main Results:

• Beef pH decreased from initial values (5.52-5.60) to 5.04-5.33 over 21 days.
• VBN values ranged from 20.53-22.59 mg/100 g, exceeding the Korean Food Code spoilage standard (20 mg/100 g).
• Raw beef showed increased psychrophilic and lactic acid bacteria, while aged beef saw decreased bacterial counts. Key contributors to high VBN included 2,3-butanedione, 2-butanone, tyrosine, and arginine.

Conclusions:

• Cold storage significantly alters physicochemical properties and microbial communities in aged beef.
• VBN levels indicate spoilage, with specific volatile compounds and amino acids contributing to degradation.
• Findings provide essential data for the beef industry to improve quality and consumer trust.