Gerson Neudí Scheuermann

Chemical composition and antimicrobial activity of essential oils from selected herbs cultivated in the South of Brazil against food spoilage and foodborne pathogens

The chemical composition of 10 selected plant essential oils obtained by steam distillation was determined by GC and GC/MS. The antimicrobial activity of the essential oils was screened against 12 important food-related bacterial strains by agar disc-diffusion assay. MIC and MBC were determined for the essential oils that presented the highest activity in the agar disc-diffusion test. The most active essential oils against the tested bacteria were, in descending order, lemongrass (Cymbopogon flexuosus), basil (Ocimum basilicum), oregano (Origanum vulgare), cinnamon leaf (Cinnamomum zeylanicum), and laurel (Laurus nobilis). Except for S. Typhimurium, the tested bateria were inhibited at MIC values lower or equal to 0.62mg mL-1 by lemongrass (Cymbopogon flexuosus) essential oil. Yersinia enterocolitica presented the highest sensitivity to all essential oils tested (CMI≤0.62mg mL-1). There was a significant correlation (P<0.05) between oxygenated monoterpenes levels in the essential oils and MIC and MBC values against Escherichia coli. Results showed that the evaluated essential oils present high potential as natural preservatives.

Período de descanso dos suínos no frigorífico e seu impacto na perda de peso corporal e em características do estômago

Pre-slaughter events might result in qualitative and quantitative losses on pig carcasses in inadequate management conditions. This study was aimed at evaluating the resting time at the processing plant (PDF= 3, 5, 7, and 9 hours) and the pen position in the lorry’s livestock compartment (PBO) on body weight loss (PPC), weight of stomach (full= PEC and empty= PEV), weight of stomach contents (PCE) and stomach lesion score (ELG) related to gastric ulcer. For this study, 192 females with average body weight of 130.0±9.9kg were used. The following effects were considered in the statistical analysis: block (season of the year), PDF, PBO and the interaction between block and PDF. There was no significant effect of PDF on the evaluated variables. For PBO, a significant effect was observed on body weight loss, with pigs transported in the frontal pens losing more body weight than those transported in middle and back pens. Eleven percent of the animals showed ELG characterizing gastric ulcer, while a high percentage of the pigs (41.9%) showed ELG grade 1, which characterizes paracheratosis. It is concluded that pigs transported in the frontal pens of the lorry’s livestock compartment do have higher body weight losses, and that increasing the resting time at the processing plant from 3 to 9 hours does not impact body weight losses or the incidence of gastric ulcer.

Investigation of glutathione peroxidase activity in chicken meat under different experimental conditions

Due to the fact that previous studies on the enzymatic activity of Glutathione peroxidase (GSH-Px) diverge widely in their methodology and results, this study aimed to investigate the influence of different analytical conditions on GSH-Px activity in chicken thighs from broilers that were fed different diets with different sources and concentrations of selenium. GSH-Px activity was evaluated six hours after slaughter and 120 days after frozen storage at -18 oC. The different analytical conditions included time of pre-incubation (0, 10 and 30 minutes), reaction medium, types of substrate (H2O2 (0.72 mM, 7.2 mM, and 72 mM) and Terc-butil hydroperoxide 15 mM), and different buffer concentrations (buffer 1, potassium phosphate 50 mM pH 7.0 + EDTA 1 mM + mercaptoethanol 1 mM, and buffer 2, tris-HCl 50 mM pH 7.6 + EDTA 1 mM + mercapthanol 5 mM). The results show that the highest GSH-Px activity was observed when enzyme and substrate were in contact at 22 oC without any pre-incubation, and that, when used at concentrations above 0.72 mM, hydrogen peroxide saturated the GSH-Px enzyme and inhibited its activity. The enzyme presented higher affinity to hydrogen peroxide when compared to terc-butil peroxide, and the addition of a buffer containing mercaptoethanol did not increase GSH-Px enzymatic activity. The activity of GSH-Px was not influenced by the source and concentration of selenium in the diet either. The obtained results allowed the determination of the best temperature of contact between the enzyme and substrate (22 oC), the optimum concentration, and the type of substrate and buffer to be used. This information is extremely useful for future studies on GSH-Px activity in meat due to the divergence and little information found in the literature.

Aflatoxins Importance on Animal Nutrition

Mycotoxins are secondary metabolites produced by several fungal species, toxic to humans, animals and plants. Their ingestion, inhalation or dermal absorption may cause different diseases and even death. These compounds have been described for many decades, howev‐ er in the beginning of the 1960s, they have been chemically characterized due to the discov‐ ery of aflatoxins [1]. The word aflatoxin is the combination of 3 other words “a” for Aspergillus genus, “fla” for the species flavus and toxin, meaning poison [2].

Current research, regulation, risk, analytical methods and monitoring results for nicarbazin in chicken meat: A perspective review

This review presents up-to-date information about current research on nicarbazin, one of the most used anticoccidials in poultry production. The focus is to elucidate regulation concerning nicarbazin, limits for its residues in food, how maximum residue limits in different countries are calculated regarding edible chicken tissues and the possible implications in human health. Analytical methods to extract and quantify this residue, expressed as dinitrocarbanilide (DNC) are presented and discussed, including qualitative screening and quantitative/confirmatory analytical methods. Monitoring results and occurrence of DNC residues in chicken meat are discussed. Additionally, the causes of eventual chicken meat contamination and possible solutions to reduce or eliminate DNC residue in tissues are also presented. The paper concludes with perspectives, the current state of DNC residue analysis and suggestions for future research, especially considering the gap in the study of residue recycling effect due to continuous chicken litter use.