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

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.

Phospholipolysis Caused by Different Types of Bacterial Phospholipases During Cold Storage of Bovine Raw Milk Is Prevented by N Gas Flushing.

Cold storage aims to preserve the quality and safety of raw milk from farms to dairies; unfortunately, low temperatures also promote the growth of psychrotrophic bacteria, some of which produce heat-stable enzymes that cause spoilage of milk or dairy products. Previously, N gas flushing of raw milk has demonstrated significant potential as a method to hinder bacterial growth at both laboratory and pilot plant scales. Using a mass spectrometry-based lipidomics approach, we examined the impact of cold storage [at 6°C for up to 7 days, the control condition (C)], on the relative amounts of major phospholipids (phosphatidylethanolamine/PE, phosphatidylcholine/PC, phosphatidylserine/PS, phosphatidylinositol/PI, and sphingomyelin/SM) in three bovine raw milk samples, and compared it to the condition that received additional N gas flushing (N).

N Gas Flushing Limits the Rise of Antibiotic-Resistant Bacteria in Bovine Raw Milk during Cold Storage.

Antibiotic resistance has been noted to be a major and increasing human health issue. Cold storage of raw milk promotes the thriving of psychrotrophic/psychrotolerant bacteria, which are well known for their ability to produce enzymes that are frequently heat stable. However, these bacteria also carry antibiotic resistance (AR) features.

Efficiency of N2 Gas Flushing Compared to the Lactoperoxidase System at Controlling Bacterial Growth in Bovine Raw Milk Stored at Mild Temperatures.

To prevent excessive bacterial growth in raw milk, the FAO recommends two options: either cold storage or activation of the lactoperoxidase system (LPs/HT) in milk with the addition of two chemical preservatives, hydrogen peroxide (H) and thiocyanate (T). N2 gas flushing of raw milk has shown great potential to control bacterial growth in a temperature range of 6-12°C without promoting undesired side effects. Here, the effect of N2 gas (N) was tested as a single treatment and in combination with the lactoperoxidase system (NHT) on seven raw milk samples stored at 15 or 25°C.

N2 Gas Flushing Alleviates the Loss of Bacterial Diversity and Inhibits Psychrotrophic Pseudomonas during the Cold Storage of Bovine Raw Milk.

The quality and safety of raw milk still remains a worldwide challenge. Culture-dependent methods indicated that the continuous N2 gas-flushing of raw milk reduced the bacterial growth during cold storage by up to four orders of magnitude, compared to cold storage alone. This study investigated the influence of N2 gas-flushing on bacterial diversity in bovine raw-milk samples, that were either cold stored at 6°C or additionally flushed with pure N2 for up to one week.