getpdf NLM PubMed Logo https://doi.org/10.17113/ftb.58.04.20.6728  Supplement 

Efficacy of Reuterin and Bacteriocins Nisin and Pediocin in the Preservation of Raw Milk from Dairy Farms

Nirmal Kumar1orcid tiny, Vinay Kumar1orcid tiny, Syed Mohsin Waheed1*orcid tiny and Diwas Pradhan2*orcid tiny

1Department of Biotechnology, Graphic Era (Deemed to be University), 566/6 Bell Road, Society Area, Clement Town, 248002 Dehradun, Uttarakhand, India

2Dairy Microbiology Division, ICARNational Dairy Research Institute, GT Rd, 132001 Karnal, Haryana, India

Article history:

Received: 2 April 2020

Accepted: 27 September 2020

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Key words:

reuterin, bacteriocins, raw milk, milk biopreservation, Lactobacillus reuteri

Summary:

Research backgroundIn the current scenario of milk production in developing and developed countries, several factors influence the shelf-life of raw milk and add significant numbers of microbial contaminants that drastically lower the initial microbial quality leading to milk spoilage by the time it reaches the processing units.

Experimental approachThe present study was undertaken to investigate the biopreservative efficacy of reuterin system along with different combinations of bacteriocins in controlling the initial microflora of raw milk at farm level. Lactobacillus reuteri strain LR47, having effective antimicrobial activity, was shortlisted from our previous study and further characterized for reuterin production and tested in raw milk system.

Results and conclusionsPreliminary testing of the cell-free supernatant from L. reuteri LR47 demonstrated significant growth inhibition of the majority of the tested bacterial indicators of milk spoilage. Further genetic analysis of the L. reuteri LR47 revealed the presence of two genes (pduC and dhaB) involved in the utilization of glycerol to produce reuterin via two different pathways. The strain LR47 was also found to possess comparatively higher capacity to convert glycerol into reuterin when checked through colourimetric assay. In the raw milk biopreservation experiment with reuterin alone or in combination with bacteriocins, the highest level of growth suppression in the total bacterial load and coliform counts was observed in the sample that was treated with a combination of reuterin, nisin and pediocin. The treatment combining these three natural biopreservatives at specific concentrations was able to maintain the initial microbial quality and extend the shelf-life of raw milk by 6 h at 37 °C based on the microbial counts and physicochemical properties, viz. pH and titratable acidity. In conclusion, the results confirm that the use of reuterin in combination with bacteriocins is a promising approach for temporary control of the raw milk microflora and extension of its shelf-life until further processing.

Novelty and scientific contributionThis study demonstrates for the first time the use of reuterin for the extension of shelf-life of raw milk as an alternative treatment method.

*Corresponding author: +911842259169
  zawidprd@gmail.com
  +919811968019
  syedmohsinwaheed@yahoo.com

getpdf NLM PubMed Logo https://doi.org/10.17113/ftb.58.04.20.6634  

Immunomodulatory Activity in vitro and in vivo of Polysaccharides from Kabuli Chickpea (Cicer arietinum L.) Hull

Hafiz Muhammad Saleem Akhtarorcid tiny, Zipeng Yeorcid tiny, Mohamed Abdinorcid tiny, Yahya Saud Hamedorcid tiny, Guijie Chenorcid tiny and Xiaoxiong Zeng*orcid tiny

College of Food Science and Technology, Nanjing Agricultural University, Weigang 1, 210095 Nanjing, PR China

 

Article history:

Received: 14 January 2020

Accepted: 2 November 2020

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Key words:

Cicer arietinum L. hull, polysaccharide fractions, immunomodulatory activity, in vitro and in vivo activity, functional food

Summary:

Research backgroundPolysaccharides isolated from plants, fungi and bacteria are associated with immunomodulatory effects. Chickpea hull, which is regarded as food industrial waste, contains considerable amounts of antioxidants and bioactive compounds.

Experimental approachIn the present study, we investigated the immunomodulatory activity of polysaccharides from kabuli chickpea (Cicer arietinum L.) hull (CHPS). In vitro study was conducted with RAW264.7 cell line while in vivo study was carried out using specific pathogen-free BALB/c mouse animal model.

Results and conclusionsIn in vitro test with RAW264.7 murine macrophage cells, the three purified fractions of chickpea hull polysaccharides showed potent immunomodulatory activity. Sample CHPS-3 showed stronger effect on cell viability, promoted the phagocytosis index to a greater extent and had the best effect on acid phosphatase activity. Moreover, it was found that CHPS-3 significantly (p<0.05) enhanced the secretion of nitrogen monoxide and cytokine (interleukins IL-6, IL-1β and tumour necrosis factor-alpha (TNF-α)) levels. In in vivo study, CHPS-3 improved thymus and spleen indices in cyclophosphamide-induced immunodeficient mice. Increased activities of lysozyme, catalase, superoxide dismutase and glutathione peroxidase, serum haemolysin content and total antioxidant capacity were observed, while the amount of malondialdehyde in the liver decreased.

Novelty and scientific contributionThe results suggest that chickpea hull polysaccharides enhanced the immune activity and could be developed as the ingredient of functional foods.

*Corresponding author: +862584396791
  +862584396791
  zengxx@njau.edu.cn

getpdf NLM PubMed Logo https://doi.org/10.17113/ftb.58.04.20.6424  

Influence of Diclofenac on Activated Sludge Bacterial Communities in Fed-Batch Reactors

Barbara Kraigher*orcid tiny and Ines Mandic-Mulecorcid tiny

University of Ljubljana, Biotechnical Faculty, Department of Food Science and Technology, Chair of Microbiology, Večna pot 111,

1000 Ljubljana, Slovenia

 

Article history:

Received: 24 June 2019

Accepted: 24 November 2020

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Key words:

activated sludge, pharmaceuticals, diclofenac, bacterial community T-RFLP, Pseudomonas

Summary:

Research background. The occurrence and environmental toxicity of pharmaceuticals have recently attracted increasing attention. Diclofenac is a highly consumed non-steroidal anti-inflammatory drug, which is often detected in wastewaters, but investigations of its influence on bacteria are scarce. 

Experimental approach. We investigated the influence of this pharmaceutical on bacterial community in activated sludge exposed to increasing concentrations of diclofenac in fed-batch reactors over 41 days. Nitrification activity of the activated sludge was measured and changes in bacterial community structure were followed using culture-independent molecular method (terminal restriction fragment length polymorphism, T-RFLP) and by the cultivation approach. 

Results and conclusions. Nitrification activity was not detectably influenced by addition of diclofenac, while the main change of the bacterial community structure was detected only at the end of incubation (after 41 days) when diclofenac was added to artificial wastewater as the only carbon source. Changes in community composition due to enrichment were also observed using cultivation approach. However, taxonomic affiliation of isolates did not match taxons identified by T-RFLP community profiling. Isolates obtained from inoculum activated sludge belonged to five genera: Comamonas, Arthrobacter, Acinetobacter, Citrobacter and Aeromonas, known for their potential to degrade aromatic compounds. However, only Pseudomonas species were isolated after the last enrichment step on minimal agar plates with diclofenac added as the sole carbon source. 

Novelty and scientific contribution. Our results suggested that the selected recalcitrant and commonly detected pharmaceutical does not strongly influence the sensitive and important nitrification process of wastewater treatment neither. Moreover, the isolated strains obtained after enrichment procedure that were able to grow on minimal agar plates with diclofenac added as the only carbon source could serve as potential model bacteria to study bacterial diclofenac degradation.

*Corresponding author: +38613203410
  +38612573390
  barbara.kraigher@bf.uni-lj.si

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