Potential of N2 Gas Flushing to Hinder Dairy-Associated Biofilm Formation and Extension

Abstract

Worldwide, the dairy sector remains of vital importance for food production despite severe environmental constraints. The production and handling conditions of milk, a rich medium, promote inevitably the entrance of microbial contaminants, with notable impact on the quality and safety of raw milk and dairy products. Moreover, the persistence of high concentrations of microorganisms (especially bacteria and bacterial spores) in biofilms (BFs) present on dairy equipment or environments constitutes an additional major source of milk contamination from pre-to post-processing stages: in dairies, BFs represent a major concern regarding the risks of disease outbreaks and are often associated with significant economic losses. One consumption trend toward "raw or low-processed foods" combined with current trends in food production systems, which tend to have more automation and longer processing runs with simultaneously more stringent microbiological requirements, necessitate the implementation of new and obligatory sustainable strategies to respond to new challenges regarding food safety. Here, in light of studies, performed mainly with raw milk, that considered dominant "planktonic" conditions, we reexamine the changes triggered by cold storage alone or combined with nitrogen gas (N 2) flushing on bacterial populations and discuss how the observed benefits of the treatment could also contribute to limiting BF formation in dairies.

The Potential Benefits of N2 Gas Flushing Technology for Various Dairy Products: A Sustainable Approach That Proved to Be Multiadvantageous for Preserving the Quality and Safety of Raw Milk During Its Storage

“…Among the opportunities to reduce waste along the journey of milk, WRAP (2018) recommended a diminution of consumers' fridge temperature or the freezing of milk; as households were found responsible for the highest waste, these actions to address food spoilage sound judicious. However, the consumer is quite deprived at the opening of spoiled milk packages (Munsch- Alatossava and Alatossava, 2020).…”

“…Different reports have described the multiple advantages of the application of N 2 gas to raw milk in which microbiological, biochemical, or technological aspects were considered; (Murray et al, 1983;Dechemi et al, 2005;Munsch-Alatossava et al, 2010a,b,c, 2013Gschwendtner et al, 2016;Munsch-Alatossava and Alatossava, 2020); in the conditions described by Munsch- Alatossava et al (2010aAlatossava et al ( , 2018 and Gschwendtner et al (2016) bacterial levels were typically lower by an over four log-units factor compared to the nonflushed conditions.…”

Microorganism Carrier-Surface Method as an Efficient Model for Microscopic Characterization of Biofilm Structure and Dispersion in Dairy Associated Spore-Forming Bacteria

“…Thus, the transfer of bacteria from biofilm through dispersion has a crucial meaning regarding cross contamination in the food industries. Cross-contamination occurs when adhered bacteria detach (dispersed cells) and contaminate the product as it passes the surface, making biofilms the main source of bacterial contamination of the final products in dairy processing plants [49,50]. Dispersion process is also important as a potential control point for the manipulation of biofilm development and novel biofilm dispersal strategies that can more effectively release biofilm-associated microbes from the protection of the EPS could improve anti-biofilm therapeutics or industrial biocides [50,51].…”