Inactivation of penicillin G in milk using hydrogen peroxide

Area of Science:

• Food Science
• Dairy Microbiology
• Analytical Chemistry

Background:

• Milk antibiotic residues, particularly penicillin G, are a significant public health concern.
• Regulatory standards, like the Grade A Pasteurized Milk Ordinance, require raw milk to be free of beta-lactam residues.
• Effective methods for inactivating these residues are crucial for ensuring milk safety.

Purpose of the Study:

• To evaluate the efficacy of different hydrogen peroxide levels and heat treatments in inactivating penicillin G in raw milk.
• To determine the optimal conditions for reducing penicillin G concentrations below the established safe limit of 5 ppb.

Main Methods:

• Raw milk was spiked with potassium penicillin G to a mean concentration of 436 ppb.
• Treatments included varying hydrogen peroxide concentrations (0.09%, 0.17%, 0.34%) combined with incubation (54.4°C for 3h) and/or pasteurization (62.8°C for 30 min).
• Penicillin G levels were quantified using a beta-lactam competitive microbial receptor assay and confirmed with HPLC.

Main Results:

• 0.09% hydrogen peroxide was ineffective in reducing penicillin G levels.
• 0.17% hydrogen peroxide with combined incubation and pasteurization reduced penicillin G to 6 ppb.
• 0.34% hydrogen peroxide with pasteurization (with or without incubation) effectively reduced penicillin G to levels well below 5 ppb.

Conclusions:

• Hydrogen peroxide at 0.34% combined with pasteurization is a highly effective method for inactivating penicillin G in raw milk.
• This treatment ensures milk safety by reducing antibiotic residues to below regulatory limits.
• Further research could explore the impact on milk quality and sensory attributes.