Effectiveness of copper ions against Mycobacterium avium subsp. paratuberculosis and bacterial communities in naturally contaminated raw cow’s milk

Abstract

Aim The focus of the present study was to evaluate the copper ions treatment on the viability of Mycobacterium avium subsp. paratuberculosis (MAP) and other bacterial communities in cow’s milk. Methods and Results A copper ions treatment was evaluated in naturally contaminated cow’s milk to assay MAP load and/or viability, and relative abundance of other bacterial communities. In addition, physical–chemical analyses of the milk were also performed. All analyses were carried out before and after a copper ions treatment. After copper ions treatment, pH and copper concentration markedly increased in milk; the numbers of viable MAP significantly decreased. The relative abundance of the four target phyla decreased, with the phyla Bacteroidetes and Firmicutes surviving treatment in higher proportions (4 and 2·1% of original populations, respectively). A progressively higher percentage of dead bacterial cells after 5 and 20 min copper ions treatments was found (12 and 35%, respectively). Conclusion With the exception of some MAP‐tolerant strains, we have once again demonstrated that copper ions have a significant inactivating effect on MAP as well as certain other bacterial communities found in naturally contaminated cow’s milk. Significance and Impact of the Study This study showed a significant inactivation of both MAP and other bacteria by copper ions in raw cow’s milk, information that could be useful as a tool for MAP control.

Is the effectivity of copper ions treatment of milk enough to block Mycobacterium avium subsp. paratuberculosis infection in calves?

“…Copper surfaces can eliminate bacterial pathogens, viruses and fungi (Faúndez et al 2004, Wilks et Recently, using an in vitro model, we showed that the use of a copper ions treatment protocol significantly reduced MAP load in PBS (Steuer et al 2018). Later, we observed that copper ions decreased viable MAP numbers in milk in a similar way (Steuer et al 2020). However, some MAP cells apparently either tolerate the effects of copper ions or repair sub-lethally damaged cells during subsequent liquid culture (Steuer et al 2018, Steuer et al 2020.…”

“…Later, we observed that copper ions decreased viable MAP numbers in milk in a similar way (Steuer et al 2020). However, some MAP cells apparently either tolerate the effects of copper ions or repair sub-lethally damaged cells during subsequent liquid culture (Steuer et al 2018, Steuer et al 2020.…”

“…Having the above mentioned in mind, maybe the copper concentrations and/ or the exposure time (8 min) may not have been enough to eliminate MAP in raw milk. Interestingly, what we know as a fact is that we previously demonstrated in PBS and also in milk, that although copper ions are highly effective in reducing MAP numbers, some MAP cells survived (Steuer et al 2018, Steuer et al 2020.…”

More Insights about the Efficacy of Copper Ion Treatment on Mycobacterium avium subsp. paratuberculosis (MAP): A Clue for the Observed Tolerance

“…In a more novel way, we have reported that copper ions, in a liquid matrix [14,15], are highly effective against Mycobacterium avium subsp. paratuberculosis (MAP), one of the most fastidious members of the Mycobacterium genus that is also highly resistant to both physical and chemical agents [16][17][18][19] and the causative agent of paratuberculosis in ruminants [20] with zoonotic potential [21].…”

Attempted Control of Paratuberculosis in Dairy Calves by Only Changing the Quality of Milk Fed to Calves

“…However, recent evidence has raised concern regarding the safety of calf milk replacer [ 14 ] and the efficacy of pasteurization [ 15 , 16 ]. For this reason, our group has explored an alternative to heat treatments, based on copper ions [ 17 , 18 ], as a means of decreasing microbial loads in raw milk. Therefore, the aim of the present study was to assess the efficacy of milk treatments to prevent MAP infection transmission to calves.…”