Biofilm formation by Listeria monocytogenes from the meat processing industry environment and the use of different combinations of detergents, sanitizers, and UV-A radiation to control this microorganism in planktonic and sessile forms.

This study aimed to evaluate the ability of biofilm formation by L. monocytogenes from the meat processing industry environment, as well as the use of different combinations of detergents, sanitizers, and UV-A radiation in the control of this microorganism in the planktonic and sessile forms. Four L. monocytogenes isolates were evaluated and showed moderate ability to form biofilm, as well as carried genes related to biofilm production (agrB, agrD, prfA, actA, cheA, cheY, flaA, sigB), and genes related to tolerance to sanitizers (lde and qacH). The biofilm-forming isolates of L. monocytogenes were susceptible to quaternary ammonium compound (QAC) and peracetic acid (PA) in planktonic form, with minimum inhibitory concentrations of 125 and 75 ppm, respectively, for contact times of 10 and 5 min. These concentrations are lower than those recommended by the manufacturers, which are at least 200 and 300 ppm for QAC and PA, respectively. Biofilms of L. monocytogenes formed from a pool of isolates on stainless steel and polyurethane coupons were subjected to 14 treatments involving acid and enzymatic detergents, QAC and PA sanitizers, and UV-A radiation at varying concentrations and contact times. All treatments reduced L. monocytogenes counts in the biofilm, indicating that the tested detergents, sanitizers, and UV-A radiation exhibited antimicrobial activity against biofilms on both surface types. Notably, the biofilm formed on polyurethane showed greater tolerance to the evaluated compounds than the biofilm on stainless steel, likely due to the material's surface facilitating faster microbial colonization and the development of a more complex structure, as observed by scanning electron microscopy. Listeria monocytogenes isolates from the meat processing industry carry genes associated with biofilm production and can form biofilms on both stainless steel and polyurethane surfaces, which may contribute to their persistence within meat processing lines. Despite carrying sanitizer tolerance genes, QAC and PA effectively controlled these microorganisms in their planktonic form. However, combinations of detergent (AC and ENZ) with sanitizers (QAC and PA) at minimum concentrations of 125 ppm and 300 ppm, respectively, were the most effective.

Phytochemical profiling, antidiabetic, antitumoral and cytotoxic potential of Psidium cattleianum Afzel. ex Sabine leaves of red variety.

In this study, phytochemical profiling, and antidiabetic, antitumoral and cytotoxic potential of aqueous extracts of leaves of red variety of Psidium cattleianum Afzel. ex Sabine were investigated. The extracts were obtained using a cellulase complex. The total phenolic compounds (TPC) were determined, and the individual phenolic compounds were quantified by HPLC-ESI-MS/MS. For the TPC, the amounts varied from 85.91 to 106.33 mg EAG g-1. Eighteen compounds have been identified. The compounds with the highest concentrations were gallic acid, quercetin and protocatechuic acid. Antidiabetic activity was obtained through α-amylase and α-glucosidase inhibition tests. The extract inhibited 17.94% of α-amylase activity and 73.34% of α-glucosidase activity. The antitumoral activity in cells of cutaneous melanoma (SK-MEL-28) and the cytotoxic activity was determined in peripheral blood mononuclear cells (PBMC). The cellular migration was determined for cells SK-MEL-28. Antitumoral effects on cells SK-MEL-28 were observed and the absence of cytotoxicity on the PBMCs.

Extrato de espinafre como fonte de nitrito em linguiça frescal: atributos de qualidade e estabilidade durante o armazenamento refrigerado / Spinach Extract as a source of nitrite in fresh sausages: quality attributes and stability during refrigerated storage

Introdução: Os consumidores têm inúmeras preocupações em relação à saúde, dentre as quais o consumo elevado de aditivos químicos, como os conservantes, que ao reagir com substâncias presentes nos alimentos podem produzir compostos cancerígenos. Alguns vegetais, como o espinafre, podem ser fontes naturais desses conservantes, e sua aplicação pode aumentar a saudabilidade dos produtos cárneos. Objetivo: Avaliar os efeitos do extrato de espinafre como fonte de nitrito para conservação de linguiças frescais, armazenadas durante 35 dias sob refrigeração. Material e Método: Quatro formulações foram produzidas: controle positivo, com sal de cura comercial (CP), controle negativo, sem sal de cura (CN), extrato de espinafre (EE) e extrato de espinafre pré-convertido por bactérias nitrato-redutoras (EEPC). As linguiças foram avaliadas através da composição centesimal, cor, teor residual de nitrito, TBARS e avaliação microbiológica. Resultados: O sal de cura (CP) resultou em menores alterações na coloração das linguiças frescais. O TBARS aumentou aproximadamente 2,5 vezes (p<0,05) ao longo dos 35 dias, em todas as formulações, e os menores valores, ao final desse período, foram encontrados nas formulações CP e EEPC. Estas mesmas formulações apresentaram os maiores teores residuais de nitrito e menor contagem de BAL e enterobactérias (35 dias), o que comprova que o EEPC é tão eficiente quanto o sal de cura comercial como conservante em linguiça frescal armazenada sob refrigeração. Conclusão: O uso de EEPC pode ser uma alternativa promissora para a indústria cárnea, possibilitando o desenvolvimento de produtos clean label que atendam à demanda por produtos mais saudáveis.

Introduction: Consumers express concerns about chemical additives in the diet, including preservatives, which can produce carcinogenic compounds when interacting with substances present in food. Some vegetables, such as spinach, can be natural sources of preservatives, and their application can increase the healthiness of meat products. Objective: To evaluate the effects of spinach extract as a source of nitrite for the preservation of fresh sausages during 35 days of refrigerated storage. Material and Method: Four formulations were produced: positive control, with commercial curing salt (CP), negative control, without curing salt (CN), spinach extract (EE) and spinach extract pre-converted by nitrate-reducing bacteria (EEPC). The sausages were evaluated for proximate composition, color parameters, residual nitrite content, TBARS, and microbiological characterization. Results: The curing salt (CP) led to a few changes in the color of the fresh sausages. TBARS increased approximately 2.5 times (p<0.05) during the 35 days for all formulations, and the lowest values were found for the formulations CP and EEPC at the end of the storage. These formulations had the highest residual nitrite levels and the lowest LAB and enterobacteria count (35 days), which proves that EEPC is an effective preservative to replace commercial curing salt in fresh sausages subjected to refrigerated storage. Conclusion: The use of EEPC can be a promising alternative for the meat industry, enabling the development of clean-label products that meet the demand for healthier products.

Extraction and characterization of phytochemical compounds from araçazeiro (Psidium cattleianum) leaf: Putative antioxidant and antimicrobial properties.

Underexplored species have phytochemical potential for pharmacological and nutraceutical applications. The fruits of such species, including aracá (Psidium cattleianum Sabine), are rich in specialized metabolites with putative antioxidant and antimicrobial activity; therefore, the leaves of these species are also a potential source of bioactive compounds. In this study, araçazeiro leaves were extracted using an aqueous infusion (Al) and a pressurized liquid extraction system with water (PLE-W), ethanol (PLE-E), and 1:1 water:ethanol ratio combination (PLE-W:E). PLE-W:E yielded a greater diversity of extracted compounds. Nonetheless, all extracts showed inhibitory activity against pathogenic Gram-positive and Gram-negative bacteria and antioxidant activity in the in vitro thiobarbituric acid reactive substances (TBARS) and reactive oxygen species (ROS) assays with rat brain and yeast model systems. Thus, araçazeiro leaves can be exploited as a promising source of bioactive compounds.