Tyramine is one of the most toxic biogenic amines and it is produced commonly by lactic acid bacteria in fermented food products. In present study, we investigated the influence of selected nisin-producing Lactococcus lactis subsp. lactis strains and their cell-free supernatants (CFSs) on tyramine production by four Lactobacillus and two Lactiplantibacillus strains isolated from cheese and beer. Firstly, we examined the antimicrobial effect of the CFSs from twelve Lactococcus strains against tested tyramine producers by agar-well diffusion assay. Six Lactococcus strains whose CFSs showed the highest antimicrobial effect on tyramine producers were further studied. Secondly, we investigated the influence of the selected six Lactococcus strains and their respective CFSs on tyramine production by tested Lactobacillus and Lactiplantibacillus strains in MRS broth supplemented with 2 g.L-1 of l-tyrosine. Tyramine production was monitored by HPLC-UV. The tyramine formation of all tested Lactobacillus and Lactiplantibacillus strains was not detected in the presence of Lc. lactis subsp. lactis CCDM 71 and CCDM 702, and their CFSs. Moreover, the remainder of the investigated Lactococcus strains (CCDM 670, CCDM 686, CCDM 689 and CCDM 731) and their CFSs decreased tyramine production significantly (P < 0.05) - even suppressing it completely in some cases - in four of the six tested tyramine producing strains.
- MeSH
- antibakteriální látky analýza metabolismus farmakologie MeSH
- kultivační média chemie metabolismus farmakologie MeSH
- Lactobacillaceae účinky léků růst a vývoj izolace a purifikace MeSH
- Lactobacillus účinky léků růst a vývoj izolace a purifikace MeSH
- Lactococcus lactis chemie metabolismus MeSH
- pivo mikrobiologie MeSH
- sýr mikrobiologie MeSH
- tyramin analýza metabolismus farmakologie MeSH
- vysokoúčinná kapalinová chromatografie MeSH
- Publikační typ
- časopisecké články MeSH
Out of six samples of wastewater produced in the dairy industry, taken in 2017 at various places of dairy operations, 86 bacterial strains showing decarboxylase activity were isolated. From the wastewater samples, the species of genera Staphylococcus, Lactococcus, Enterococcus, Microbacterium, Kocuria, Acinetobacter, Pseudomonas, Aeromonas, Klebsiella and Enterobacter were identified by the MALDI-TOF MS and biochemical methods. The in vitro produced quantity of eight biogenic amines (BAs) was detected by the HPLC/UV-Vis method. All the isolated bacteria were able to produce four to eight BAs. Tyramine, putrescine and cadaverine belonged to the most frequently produced BAs. Of the isolated bacteria, 41% were able to produce BAs in amounts >100 mg L-1. Therefore, wastewater embodies a potential vector of transmission of decarboxylase positive microorganisms, which should be taken into consideration in hazard analyses within foodstuff safety control. The parameters of this wastewater (contents of nitrites, nitrates, phosphates, and proteins) were also monitored.
- MeSH
- Acinetobacter MeSH
- Aeromonas MeSH
- biogenní aminy chemie MeSH
- chemické látky znečišťující vodu chemie izolace a purifikace MeSH
- Enterobacter MeSH
- Enterococcus MeSH
- karboxylyasy chemie MeSH
- Klebsiella MeSH
- Lactobacillus MeSH
- Lactococcus MeSH
- Microbacterium MeSH
- mikrobiologie vody MeSH
- mlékárenství * MeSH
- odpadní voda analýza mikrobiologie MeSH
- Pediococcus MeSH
- Pseudomonas MeSH
- spektrofotometrie ultrafialová MeSH
- spektrometrie hmotnostní - ionizace laserem za účasti matrice MeSH
- Staphylococcus MeSH
- Streptococcus MeSH
- vysokoúčinná kapalinová chromatografie MeSH
- Publikační typ
- časopisecké články MeSH
- Geografické názvy
- Evropa MeSH
Degradation of undesirable biogenic amines (BAs) in foodstuffs by microorganisms is considered one of the most effective ways of eliminating their toxicity. In this study, we designed two sets of primers for the detection and quantification of the multicopper oxidase gene (MCO), which encodes an enzyme involved in BAs degradation, and endogenous (glyceraldehyde-3-phosphate dehydrogenase) gene (GAPDH) in Lactobacillus casei group by real-time PCR (qPCR). We tested 15 Lactobacillus strains in the screening assays (thus, MCO gene possessing assay (PCR) and monitoring of BAs degradation by HPLC-UV), in which Lactobacillus casei CCDM 198 exhibited the best degradation abilities. For this strain, we monitored the expression of the target gene (MCO) in time (qPCR), the effect of redox treatments (cysteine, ascorbic acid) on the expression of the gene, and the ability to degrade BAs not only in a modified MRS medium (MRS/2) but also in a real food sample (milk). Moreover, decarboxylase activity (ability to form BAs) of this strain was excluded. According to the results, CCDM 198 significantly (P < 0.05) reduced BAs (putrescine, histamine, tyramine, cadaverine), up to 25% decline in 48 h. The highest level of relative expression of MCO (5.21 ± 0.14) was achieved in MRS/2 media with cysteine.
- MeSH
- bakteriální proteiny genetika metabolismus MeSH
- biogenní aminy analýza metabolismus MeSH
- cystein analýza metabolismus MeSH
- glyceraldehyd-3-fosfátdehydrogenasy genetika MeSH
- kultivační média chemie MeSH
- kvantitativní polymerázová řetězová reakce MeSH
- kyselina askorbová analýza metabolismus MeSH
- Lactobacillus casei enzymologie genetika růst a vývoj metabolismus MeSH
- Lactobacillus enzymologie genetika růst a vývoj metabolismus MeSH
- mléko chemie MeSH
- oxidoreduktasy genetika metabolismus MeSH
- regulace genové exprese u bakterií MeSH
- vysokoúčinná kapalinová chromatografie MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
The aim of the study is to model concentrations of selected biogenic amines in various fish species (Atlantic salmon, Atlantic cod, striped catfish) bought in retail stores in Central Europe. Since the data contains non-detectable values, statistical methods for left-censored values from the exponential and Weibull distributions are applied and used to evaluate and compare the amount of biogenic amines in fish samples. Moreover, a risk of exceeding certain limits of biogenic amine concentrations to protect human health is determined. There are relatively high concentrations of putrescine, cadaverine and histamine in almost all fish species. Moreover, there was a significant difference in mean concentrations (distributions of concentrations, respectively) of histamine, tyramine and spermidine among the species.
- MeSH
- biogenní aminy chemie metabolismus MeSH
- histamin metabolismus MeSH
- kadaverin metabolismus MeSH
- lidé MeSH
- maso analýza MeSH
- monitorování životního prostředí MeSH
- putrescin metabolismus MeSH
- ryby metabolismus MeSH
- spermidin MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- Geografické názvy
- Evropa MeSH
The aim of this work was to add various amounts of rework (0.0 to 20.0% wt/wt) to processed cheeses with a dry matter content of 36% (wt/wt) and fat with a dry matter content of 45% (wt/wt). The effect of the rework addition on the viscoelastic properties and microstructure of the processed cheeses was observed. The addition of rework (in this case, to processed cheese with a spreadable consistency) in the amounts of 2.5, 5.0, and 10.0% (wt/wt) increased the firmness of the processed cheese. With the further addition of rework, the consistency of the processed cheeses no longer differed significantly. The conclusions obtained by the measurement of viscoelastic properties were supported by cryo-scanning electron microscopy, where fat droplets in samples with added rework of over 10.0% (wt/wt) were smaller than fat droplets in processed cheeses with lower additions of rework.
- MeSH
- časové faktory MeSH
- manipulace s potravinami metody MeSH
- sýr analýza MeSH
- Publikační typ
- časopisecké články MeSH
The basic raw materials for the production of processed cheese are natural cheese which is treated by heat with the addition of emulsifying salts. From a point of view of the melting temperatures used (and the pH-value of the product), the course of processed cheese production can be considered "pasteurisation of cheese." During the melting process, the majority of vegetative forms of microorganisms, including bacteria of the family Enterobacteriaceae, are inactivated. The melting temperatures are not sufficient to kill the endospores, which survive the process but are often weakened. From a microbiological point of view, the biggest contamination problem of processed cheese is caused by gram-positive spore-forming rod-shaped bacteria of the genera Bacillus, Geobacillus, and Clostridium. Other factors affecting the shelf-life and quality of processed cheese are mainly the microbiological quality of the raw materials used, strict hygienic conditions during the manufacturing process as well as the type of packaging materials and storage conditions. The quality of processed cheese is not only dependent on the ingredients used but also on other parameters such as the value of water activity of the processed cheese, its pH-value, the presence of salts and emulsifying salts and the amount of fat in the product.
The aim of this work was to examine the effect of a different dry matter (DM) contents (35 and 45% wt/wt) and fat in DM contents (40 and 50% wt/wt) on the textural and viscoelastic properties and microstructure of model processed cheeses made from real ingredients regularly used in the dairy industry. A constant DM content and constant fat in DM content were kept throughout the whole study. Apart from the basic chemical parameters, textural and viscoelastic properties of the model samples were measured and scanning electron microscopy was carried out. With increasing DM content, the rigidity of the products increased and the size of the fat globules in the model samples of the processed cheeses decreased. With increasing fat in DM content, the rigidity of the processed cheeses decreased and the size of the fat globules increased.
- MeSH
- glykolipidy analýza chemie MeSH
- glykoproteiny analýza chemie MeSH
- manipulace s potravinami MeSH
- mikroskopie elektronová rastrovací MeSH
- pružnost MeSH
- sýr analýza MeSH
- viskozita MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
BACKGROUND: The present study examined the influence of eight selected strains of Penicillium nalgiovense as secondary culture on the ripening of soft mould cheese. Ion-exchange chromatography, SDS-PAGE and sensory analysis were used for comparison of P. nalgiovense with common secondary mould culture (Penicillium camemberti). RESULTS: Proteolytic activity was more intensive in the case of the strains of P. nalgiovense in comparison with the control strains of P. camemberti. Some differences in the proportion and amount of free amino acids were observed between the strains of P. nalgiovense during ripening. Lower proteolytic activity of P. nalgiovense was more desirable for sensory properties of cheese, especially in case sample N2. CONCLUSION: This study provides information on the usability of selected strains of P. nalgiovense that could support the development of sensory properties of mould-ripened soft cheese. The cheese with the culture N2 had the best flavour after 35 days of storage. Moreover, this strain showed the lowest bitterness in comparison with the other used P. nalgiovense cultures. The intensity of bitterness of sample N2 was comparable to that of the control sample with P. camemberti. © 2015 Society of Chemical Industry.
The aim of this study was to evaluate the combined effect of temperature (10, 20 and 37°C), pH (4, 5, 6, 7 and 8), and NaCl content (0, 1, 3, 4, 5 and 6% w/v) on the growth and putrescine and cadaverine production of Serratia marcescens CCM 303 under model conditions. The decarboxylase activity of S. marcescens was monitored in broth after cultivation. The cultivation medium was enriched with selected amino acids (ornithine, arginine and lysine; 0.2% w/v each) serving as precursors of biogenic amines. Levels of putrescine and cadaverine in broth were analysed by high-performance liquid chromatography after pre-column derivatisation with o-phthalaldehyde reagent. S. marcescens produced higher amounts of putrescine (up to 2096.8 mg L(-1)) compared to cadaverine content (up to 343.3 mg L(-1)) in all cultivation media. The highest putrescine and cadaverine concentrations were reached during cultivation at 10-20°C, pH 5-7 and NaCl content 1-3% w/v. On the other hand, the highest BAs production of individual cell (recalculated based on a cell; so called "yield factor") was observed at 10°C, pH 4 and salt concentration 3-5% w/v as a response to environmental stress.
- MeSH
- biogenní aminy metabolismus MeSH
- chlorid sodný farmakologie MeSH
- kadaverin analýza biosyntéza MeSH
- koncentrace vodíkových iontů MeSH
- kultivační média chemie farmakologie MeSH
- putrescin analýza biosyntéza MeSH
- Serratia marcescens účinky léků růst a vývoj metabolismus MeSH
- teplota MeSH
- vysokoúčinná kapalinová chromatografie MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Highly undesirable microbial contaminants of processed cheese are endospore-forming bacteria of the genera Bacillus and Clostridium. Survival of Bacillus subtilis, B. cereus, Clostridium butyricum and C. sporogenes was examined in model processed cheese samples supplemented with monoacylglycerols. In processed cheese samples, monoacylglycerols of undecanoic, undecenoic, lauric and adamantane-1-carboxylic acid at concentration of 0.15% w/w prevented the growth and multiplication of both Bacillus species throughout the storage period. The two species of Clostridium were less affected by monoacylglycerols in processed cheese samples and only partial inhibition was observed. The effect of milk fat content on microbial survival in processed cheese was also evaluated. The growth of Bacillus sp. was affected by the fat level of processed cheese while population levels of Clostridium sp. did not differ in processed cheese samples with 30, 40 and 50% fat in dry matter.
- MeSH
- antiinfekční látky farmakologie MeSH
- Bacillus účinky léků MeSH
- Clostridium účinky léků růst a vývoj MeSH
- monoglyceridy farmakologie MeSH
- potravinářská mikrobiologie * MeSH
- potravinářské přísady farmakologie MeSH
- sýr mikrobiologie MeSH
- tuky metabolismus farmakologie MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
