Report on the Field Testing and Evaluation of Air Liquide’s CO2+ Process and Pathogen Reduction during a Meat Mixing Process

Introduction: “CO2+” is a proprietary process developed by Air Liquide that allows for the introduction of a biocide (or other liquid food processing aid) directly into the stream of liquid CO₂ prior to bottom injection into a meat mixer.  

Purpose: The CO2+ process delivers accurate doses of prescribed biocide such that a small volume of biocide (less than one liter per 1,000 pound batch size) can be evenly distributed throughout the entire mass of meat during the standard liquid CO₂ injection cycle.  Air Liquide and the USDA-ARS Wyndmoor, PA, have collaborated in a Cooperative Research and Development Agreement to investigate the effectiveness of antimicrobial agents in the reduction of pathogenic bacteria such as Salmonella, E. coli, Listeria, and Campylobacter both in lab and full-scale process.   

Methods: Antimicrobial agents were identified and tested in the lab for their effectiveness in reducing bacterial load.  Six of these antimicrobials were selected for field testing in full-sized meat batches utilizing bottom injection liquid CO₂ chilling technology. Antimicrobial agents were introduced throughout the meat mix via Air Liquide’s CO2+ process.  Samples were collected and sent to an independent laboratory for processing.

Results: Testing showed that all of these antimicrobials were effective against Salmonella on poultry trim products. Results showed a pH reduction ranging from 5.8 to less than 4.0, and a reduction of up to 2 logs in APC and Enterobacteriaceae, depending on dosage and antimicrobial product.

Significance: New technology for pathogen reduction in ground and trim meat products.