Milk substrates influence proteolytic activity of Pseudomonas fluorescens strains

Colantuono, Antonio; D’Incecco, Paolo; Fortina, María Grazia; Rosi, Veronica; Ricci, Giovanni; Pellegrino, L.

doi:10.1016/j.foodcont.2019.107063

Cited by 22 publications

(20 citation statements)

References 41 publications

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“…On the other hand, faster growth of B. cereus in pasteurized milk at 30 °C with maximum reached after 8 hours of incubation described Wong et al, (1988). The final counts of P. fluorescens after 144 h incubation at 6.5 °C and after 48 h at 22 °C were lower than that reported by Colantuono et al (2020) for 4 °C and 25 °C but close to values found by Miguel et al (2019) for incubations at 7 °C for 6 days. Discrepancies in the growth parameters of bacteria can be explained by a different composition of culture medium or incubation conditions.…”

Section: Growth Of Bacteriasupporting

confidence: 74%

Effect of Increasing Zearalenone Levels on the Technologically Problematic Microorganisms and Food Risky Pathogens (in Vitro)

Křížová¹,

Klimešová²,

Hanuš³

et al. 2021

Acta Univ. Agric. Silvic. Mendelianae Brun.

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The aim of this study was to determine the effect of different zearalenone (ZEA) concentrations (0, 10, 100, 250, 500, 1 000 µg/l) on growth of Bacillus cereus, Staphylococcus aureus and Pseudomonas fluorescens in milk. The samples were incubated for 6 days at 22 and 30 °C (B. cereus and S. aureus) or at 6.5 and 22 ℃ (P. fluorescens), respectively. Counts of bacteria in milk were measured every 24 hours. Maximum counts of B. cereus after 144 h of incubation at 30 ℃ ranged from 7.00 to 7.78 log CFU/ml. The most significant effect of ZEA on B. cereus across the experiment was observed after 96 h of incubation at 22 °C and after 72 h at 30 °C (P < 0.001 and P < 0.01, respectively). S. aureus maintained at 30 °C showed similar growth parameters as at 22 ℃ regardless of ZEA presence. The most significant effects of ZEA on S. aureus were after 120 h of incubation at 22 °C and after 72 h at 30 °C (P < 0.001). The growth of P. fluorescence at 6.5 °C was slower compared to growth at 22 °C. The most significant effect of ZEA between ZEA spiked and Z0 samples on P. fluorescence across the experiment was observed after 48 hours of incubation at 22 °C (P < 0.001).

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Section: Growth Of Bacteriasupporting

confidence: 74%

Effect of Increasing Zearalenone Levels on the Technologically Problematic Microorganisms and Food Risky Pathogens (in Vitro)

Křížová¹,

Klimešová²,

Hanuš³

et al. 2021

Acta Univ. Agric. Silvic. Mendelianae Brun.

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“…isolated from raw bovine milk exhibited much more variation than we observed in low-temperature proteolysis for these 3 species groups (Meng et al, 2017). Identification of spoilage-associated enzymatic activities in pure culture systems provides initial data on spoilage capabilities of isolates; however, it should be noted that spoilage expression in fluid milk may depend on additional variables, such as prior heat treatment, storage conditions, and presence of additional types of bacteria (Worm et al, 2000;Nicodème et al, 2005;Colantuono et al, 2020). Future studies may benefit from correlating spoilage phenotypes with presence and genotype of the aprX-lipA operon, which encodes extracellular protease and lipase enzymes that may be associated with product degradation (Woods et al, 2001;Zhang et al, 2019).…”

Section: Iles At Is Associated With Relevant Spoilage Enzyme Productionmentioning

confidence: 77%

Identification, subtyping, and tracking of dairy spoilage-associated Pseudomonas by sequencing the ileS gene

Reichler

Murphy

Martin

et al. 2021

Journal of Dairy Science

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Pseudomonas spp. are important spoilage bacteria that negatively affect the quality of refrigerated fluid milk and uncultured cheese by generating unwanted odors, flavors, and pigments. They are frequently found in dairy plant environments and enter dairy products predominantly as postpasteurization contaminants. Current subtyping and characterization methods for dairy-associated Pseudomonas are often labor-intensive and expensive or provide limited and possibly unreliable classification information (e.g., to the species level). Our goal was to identify a single-copy gene that could be analyzed in dairy spoilage-associated Pseudomonas for preliminary species-level identification, subtyping, and phenotype prediction. We tested 7 genes previously targeted in a Pseudomonas fluorescens multilocus sequence typing scheme for their individual suitability in this application using a set of 113 Pseudomonas spp. isolates representing the diversity of typical pasteurized milk contamination. For each of the 7 candidate genes, we determined the success rate of PCR and sequencing for these 113 isolates as well as the level of discrimination for species identification and subtyping that the sequence data provided. Using these metrics, we selected a single gene, isoleucyl tRNA synthetase (ileS), which had the most suitable traits for simple and affordable single-gene Pseudomonas characterization. This was based on the number of isolates successfully sequenced for ileS (113/113), the number of unique allelic types assigned (83, compared with 50 for 16S rDNA), nucleotide and sequence diversity measures (e.g., number of unique SNP and Simpson index), and tests for genetic recombination. The discriminatory ability of ileS sequencing was confirmed by separation of 99 additional dairy Pseudomonas spp. isolates, which were indistinguishable by 16S rDNA sequencing, into 28 different ileS allelic types. Further, we used wholegenome sequencing data to demonstrate the similarities in ileS-based phylogenetic clustering to whole-genomebased clustering for 27 closely related dairy-associated Pseudomonas spp. isolates and for 178 Pseudomonas type strains. We also found that dairy-associated Pseudomonas within an ileS cluster typically shared the same proteolytic and lipolytic activities. Use of ileS sequencing provides a promising strategy for affordable initial characterization of Pseudomonas isolates, which will help the dairy industry identify, characterize, and track Pseudomonas in their facilities and products.

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“…In the present investigation, UHT skimmed milk was used because its shelf-life is much better compared to extended shelf-life milk or unheated natural milk. Furthermore, the chance of the coagulation of proteins in UHT milk due to the application of trypsin and microbial proteolysis is negligible, compared to extended shelf-life milk and unheated natural milk [28].…”

Section: Ultra-heat-treated (Uht) Skimmed Cow's Milkmentioning

confidence: 99%

“…Therefore, peptides with unique biological activities are produced by the catalytic activity of endopeptidase. The activity of proteolytic enzymes alters their fluid and organoleptic properties [28,29]. Furthermore, the cost of the downstream process, developed using membrane-based filtration and chromatography to isolate the targeted peptide from the reaction mixture, increases the overall processing cost [30].…”

Section: Introductionmentioning

confidence: 99%

Bioactive Peptides from Liquid Milk Protein Concentrate by Sequential Tryptic and Microbial Hydrolysis

et al. 2021

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Recently, bioactive peptides as a health-promoting agent have come to the forefront of health research; however, industrial production is limited, possibly due to the lack of the required technological knowledge. The objective of the investigation was to prepare bioactive peptides with hypoallergenic properties from liquid milk protein concentrate (LMPC), through sequential enzymatic and microbial hydrolysis. LMPC was produced from ultra-heat-treated (UHT) skimmed cow’s milk using a nanofiltration membrane. The effect of the concentration of trypsin (0.008–0.032 g·L−1) on the hydrolysis of LMPC was studied. Subsequently, the hydrolysis of tryptic-hydrolyzed LMPC (LMPC-T) with lactic acid bacteria was performed, and the effect of glucose in microbial hydrolysis was studied. Aquaphotomic analysis of the hydrolysis of LMPC was performed using the spectral range of 1300–1600 nm (near-infrared spectra). Changes in antioxidant capacity, anti-angiotensin-converting enzyme activity, and antibacterial activity against Bacillus cereus, Staphylococcus aureus and Listeria monocytogenes were noted after the sequential tryptic and microbial hydrolysis of LMPC. Allergenicity in LMPC was reduced, due to sequential hydrolysis with 0.016 g·L−1 of trypsin and lacteal acid bacteria. According to the aquaphotomic analysis result, there was a dissociation of hydrogen bonds in compounds during the initial period of fermentation and, subsequently, the formation of compounds with hydrogen bonds. The formation of compounds with a hydrogen bond was more noticeable when microbial hydrolysis was performed with glucose. This may support the belief that the results of the present investigation will be useful to scale up the process in the food and biopharmaceutical industries.

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Milk substrates influence proteolytic activity of Pseudomonas fluorescens strains

Cited by 22 publications

References 41 publications

Effect of Increasing Zearalenone Levels on the Technologically Problematic Microorganisms and Food Risky Pathogens (in Vitro)

Effect of Increasing Zearalenone Levels on the Technologically Problematic Microorganisms and Food Risky Pathogens (in Vitro)

Identification, subtyping, and tracking of dairy spoilage-associated Pseudomonas by sequencing the ileS gene

Bioactive Peptides from Liquid Milk Protein Concentrate by Sequential Tryptic and Microbial Hydrolysis

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