Putrefactive Amine Changes in Relation to Microbial Counts of Ground Beef During Storage.

Area of Science:

• Food Science
• Microbiology
• Analytical Chemistry

Background:

• Biogenic amines are compounds formed by microbial decarboxylation of amino acids.
• Their presence in food can indicate microbial activity and spoilage.
• Understanding amine formation in raw ground beef is crucial for food safety.

Purpose of the Study:

• To evaluate seven specific amines as potential indicators of bacterial contamination in raw ground beef.
• To correlate amine concentrations with total, psychrotrophic, and coliform bacterial counts during refrigerated storage.
• To assess the relationship between amine levels and the percentage of lysine decarboxylase-positive bacteria.

Main Methods:

• Raw ground beef was stored for 12 days at 4, 7, and 10°C.
• Amine analysis was performed using extraction, ion exchange chromatography, and ninhydrin detection at 2-day intervals.
• Lysine decarboxylase-positive bacteria (LD+) were quantified at 4°C.
• Correlation and regression analyses were employed to link amine concentrations with bacterial counts.

Main Results:

• Total and psychrotrophic bacterial counts reached up to 10^9 bacteria/g.
• Putrescine, 1,3-diaminopropane, tyramine, cadaverine, and spermidine showed significant correlations with total and psychrotrophic bacteria.
• Cadaverine was the sole amine significantly correlated with coliform counts (P≥0.95).
• The percentage of LD+ bacteria increased up to day 6, then decreased.

Conclusions:

• Specific amines like putrescine, 1,3-diaminopropane, tyramine, cadaverine, and spermidine can serve as reliable indicators for total and psychrotrophic bacterial growth in raw ground beef.
• Cadaverine is a potential indicator for coliform contamination in raw ground beef.
• Amine profiling offers a valuable tool for assessing the microbial quality and safety of raw ground beef during storage.