Don, F-2 and T-2 mycotoxin assay of plant-based feedstock raw materials using the ELISA method

In our study, plant-based raw materials, used for feeding different animal species, are investigated, using a competitive ELISA method. The raw materials most commonly used for feeding (soy and alfalfa pellets, as well as wheat, barley and maize) were used in the tests. Of Fusarium mycotoxins, deoxynivalenol (DON), zearalenone (F-2) and T-2 toxins were measured. Measurement results were evaluated using the mathematical- statistical program RStudio. In our experiment, we found that all three mycotoxins tested could be detected in all of the samples, but the values were not quantifiable with acceptable precision in each case. The average detected DON toxin result was an order of magnitude greater than the results of the other toxins. It has been shown in our study that the presence of the mycotoxins deoxynivalenol, zearalenone and T-2 poses a serious food and feed safety risk, since they are present in feedstock raw materials, even though only in small amounts. Today, these mycotoxins are present together in more and more cases, greatly increasing the above-mentioned risk

Distribution of bacterial single cell parameters and their estimation from turbidity detection times

The stochastic growth of homogeneous bacterial populations in the wells of a microtiter plate was studied as a function of the random initial cell number and their random individual lag times. These significantly affected the population growth in the well, while the maximum specific growth rate of the population was constant (or its variance was negligible) for each well. We showed the advantages of the mathematical assumption that a transformation of the single cell lag time, called the single cell physiological state (or, more accurately, that of the sub-population generated by the single cell) follow the Beta distribution. Simulations demonstrated what patterns would such assumption generate for the distribution of the detection times observed in the wells. An estimation procedure was developed, based on the beta-assumption, that resulted in an explicit expression for the expected value of the single cell physiological state as a function of measured “time to detection” values using turbidity experiments. The method was illus- trated using laboratory data with Escherichia coli, Salmonella enterica subsp. enterica strains. The results gave a basis to quantify the difference between the studied organisms in terms of their single-cell kinetics

Takarmányozásra használt növényi alapanyagok DON, F-2, T-2 mikotoxin-vizsgálata ELISA-módszerrel

Tanulmányunkban különböző állatfajok etetésére használt növényi alapanyagokat vizsgáltunk kompetitív ELISA-módszerrel. A vizsgálatok során takarmányozáshoz legygyakrabban használt alapanyagokkal (szója- és lucerna-pellet, valamint búza, árpa és kukorica) dolgoztunk. A Fusarium mikotoxinok közül a deoxinivalenol (DON), zearalenon (F-2) és a T-2 toxinokat mértünk. A mérési eredményeinket RStudio matematikai-statisztikai programmal értékeltük. Kísérletünkben megállapítottuk, hogy mindhárom vizsgált mikotoxin detektálható - volt mindegyik mintában, de nem mindegyikben volt mennyiségileg elfogadható pontossággal meghatározható érték. A detektált DON toxin eredmények átlagértéke egy nagyságrenddel nagyobbnak bizonyult a többi toxinnál. Vizsgálatunk során bizonyítást nyert, hogy a deoxinivalenol, zearalenon és T-2 mikotoxinok jelenléte komoly takarmány- és élelmiszer-biztonsági veszélyt jelent, hiszen ha csak kis mennyiségekben is, de jelen vannak már a takarmány-alapanyagokban. Napjainkban egyre több esetben fordul elő ezen mikotoxinok együttes jelenléte, ami nagymértékben sokszorozza az előbb említett kockázatot

Production of Hypoallergenic Antibacterial Peptides from Defatted Soybean Meal in Membrane Bioreactor: A Bioprocess Engineering Study with Comprehensive Product Characterization

Hipoalergeni antibakterijski peptidi male molekularne mase proizvedeni su iz nemasne sojine sačme u membranskom bioreaktoru. U prvom su koraku proteini sojine sačme razgrađeni pomoću tripsina u šaržnom bioreaktoru. Optimalni uvjeti za razgradnju tripsinom bili su: koncentracija sojine sačme od 75 g/L, temperatura od 40 °C i pH=9. Nakon toga su peptidi male molekularne mase pročišćeni pomoću „cross-flow“ membrane (veličina pora 100 μm), a zatim pomoću keramičke cjevaste membrane (veličine pora koja ne propušta molekule veće od 5 kDa). Ispitan je utjecaj transmembranskog pritiska i primjene statičkih promotera turbulencije na smanjenje koncentracijske polarizacije blizu površine ultrafiltracijske membrane, te je potvrđen njihov pozitivan učinak. Transmembranski pritisak od 3•105 Pa i diskontinuirana dijafiltracija provedena u tri koraka bili su optimalni za filtraciju pomoću ultrafiltracijske membrane. Distribucija molekularne mase peptida pročišćenih pomoću ultrafiltracijske membrane utvrđena je pomoću metode LC-ESI-Q-TOF-MS. Više od 96 % peptida (izraženih kao relativna frekvencija) iz permeata ultrafiltracijske membrane imalo je molekularnu masu manju od 1,7 kDa, a najveća je molekularna masa bila 3,1 kDa. Smanjenje alergenih svojstava proteina za više od 99,9 % nakon obrade tripsinom i membranske filtracije utvrđeno je imunoenzimskim testom. Također je zaključeno da peptidi pročišćeni pomoću ultrafiltracijske membrane pozitivno djeluju na rast bakterije Pediococcus acidilactici HA6111-2, te sprečavaju rast bakterije Bacillus cereus.Hypoallergenic antibacterial low-molecular-mass peptides were produced from defatted soybean meal in a membrane bioreactor. In the first step, soybean meal proteins were digested with trypsin in the bioreactor, operated in batch mode. For the tryptic digestion of soybean meal protein, optimum initial soybean meal concentration of 75 g/L, temperature of 40 °C and pH=9.0 were determined. After enzymatic digestion, low-molecular-mass peptides were purified with cross-flow flat sheet membrane (pore size 100 μm) and then with tubular ceramic ultrafiltration membrane (molecular mass cut-off 5 kDa). Effects of transmembrane pressure and the use of a static turbulence promoter to reduce the concentration polarization near the ultrafiltration membrane surface were examined and their positive effects were proven. For the filtration with ultrafiltration membrane, transmembrane pressure of 3·10^5 Pa with 3-stage discontinuous diafiltration was found optimal. The molecular mass distribution of purified peptides using ultrafiltration membrane was determined by a liquid chromatography–electrospray ionization quadrupole time-of-flight mass spectrometry setup. More than 96 % of the peptides (calculated as relative frequency) from the ultrafiltration membrane permeate had the molecular mass M≤1.7 kDa and the highest molecular mass was found to be 3.1 kDa. The decrease of allergenic property due to the tryptic digestion and membrane filtration was determined by an enzyme-linked immunosorbent assay and it was found to exceed 99.9 %. It was also found that the peptides purifi d in the ultrafi tration membrane promoted the growth of Pediococcus acidilactici HA6111-2 and they possessed antibacterial activity against Bacillus cereus