Hydrogel properties of non-conventional starches from guabiju, pinhão, and uvaia seeds.

The physicochemical properties of starch vary depending on the botanical sources, thereby influencing the gelatinisation/retrogradation properties and subsequently affecting the hydrogels characteristics. This study aimed to assess the influence of botanical sources influence on starch and hydrogel properties using non-conventional starch derived from guabiju, pinhão, and uvaia seeds. Hydrogels were prepared by starch gelatinisation followed by 6 h ageing period at room temperature (20 ± 2 °C) and subjected to five freeze-thaw cycles. Pinhão starch exhibited a higher viscosity peak and breakdown, along with a lower final viscosity and setback, compared to guabiju and uvaia starches. The significantly different pasting properties influenced the porous microstructure, water absorption (p-value: 0.01), and resistance of the hydrogels (p-value: 0.01). The guabiju starch hydrogels showed a uniform pore structure without cavities, whereas pinhão and uvaia starch hydrogels exhibited agglomerated and spongy pore structures. Furthermore, the guabiju starch hydrogel demonstrated the lowest water absorption (4.56 g/g) and the highest compression resistance (1448.50 g) among all the studied starch hydrogels. In contrast, the pinhão starch hydrogel showed the highest water absorption (7.43 g/; p-value: 0.01) among all studied starch hydrogels. The hardness of uvaia starch hydrogel did not differ significantly from the guabiju and pinhão starch hydrogel. The different non-conventional starches reveal important variations in the hydrogels characteristics. This provides insights into how amylose and amylopectin interact and present alternatives for using these unique starch-based hydrogels in diverse applications.

Antilisterial activity of cinnamon essential oil, pomegranate extract, or strawberry tree extract against Listeria monocytogenes in slices of dry-cured ham and pork loin.

Owing to concerns about the antimicrobial resistance of agents that can prevent the growth of Listeria monocytogenes in meat, researchers have investigated natural preservatives with antilisterial effects. However, in vivo application of essential oils and plant extracts usually results in reduced antimicrobial activity in meat products when compared to in vitro studies. This study aimed to evaluate the in vivo antimicrobial activity of cinnamon essential oil, pomegranate, and strawberry tree extracts in slices of dry-cured ham and pork loin against L. monocytogenes. Fragments of sterile dry-cured ham were inoculated with 100 µL cinnamon oil 0.5%, pomegranate, or strawberry crude extract. After 10 min, 100 µL of L. monocytogenes serotype 4b (104 colony-forming unit [CFU]/mL) was inoculated, and samples were incubated at 7 °C for 7 d to simulate the processing and storage temperature conditions of dry-cured meat products. L. monocytogenes was detected and quantified. Only strawberry extract presented significant differences (P < 0.05) from the control; thus, it was selected for the assay with 2% and 4% salt-treated pork loin. The strawberry tree extract significantly (P < 0.05) reduced the growth of L. monocytogenes in dry-cured ham. However, it could not reduce L. monocytogenes growth in pork loin, regardless of the salt concentration. This is the first report on the antimicrobial effect of strawberry tree leaf extract against L. monocytogenes in dry-cured ham.

Brazilian native fruit pomace as a source of bioactive compounds on starch-based films: Antimicrobial activities and food simulator release.

The bioactive compounds extraction from fruit pomace is an ecological alternative for these abundant and low-added-value by-products. This study aimed to evaluate the antimicrobial potential of pomace extracts from Brazilian native fruits (araçá, uvaia, guabiroba and butiá) and the effect on physicochemical, mechanical properties and the migration of antioxidants and phenolic compounds from starch-based films. The film with butiá extract had the lowest mechanical resistance (1.42 MPa) but the highest elongation (63 %). In comparison, uvaia extract had less impact on film mechanical properties (3.70 MPa and 58 %) compared to the other extracts. The extracts and films showed antimicrobial activity against Listeria monocytogenes, L. inoccua, B. cereus and S. aureu. Approximately 2 cm inhibition halo was noticed for the extracts, while films ranged from 0.33 to 1.46 cm inhibition halo. Films with guabiroba extract had the lowest antimicrobial activity (0.33 to 0.5 cm). The phenolic compounds were released from the film matrix in the first hour at 4 °C with maintenance in the stability. The fatty-food simulator showed a controlled release of antioxidant compounds, which can assist in controlling food oxidation. Brazilian native fruit has shown to be a viable alternative to isolate bioactive compounds and produce film packaging with antimicrobial and antioxidant activities.

Genomic characterization of multidrug-resistant Salmonella Heidelberg E2 strain isolated from chicken carcass in southern Brazil.

Salmonella Heidelberg is a clinically-important serovar linked to food-borne illness, and commonly isolated from poultry products. Since 1962, Salmonella Heidelberg has been widely reported from poultry production systems in several countries, including Brazil. The emergence of multidrug-resistant (MDR) Salmonella Heidelberg strains in food animals underscores a significant food safety hazard. In our study, we performed antimicrobial susceptibility testing (AST) and Whole-genome sequencing (WGS) to identify the antimicrobial resistance (AMR) genes, pathogenicity mechanisms and virulence factors (VF) in Salmonella Heidelberg E2 strain recovered from a chicken carcass in Southern Brazil. Salmonella Heidelberg strain belonged to ST15 and showed to be susceptible to colistin (MIC ≤2 µg/mL) and multidrug-resistant to amoxicillin-clavulanic acid, gentamicin, ampicillin, cefaclor, cefazolin, ceftiofur, nalidixic acid, azithromycin, erythromycin, doxycycline, tetracycline and sulfonamide. We identified AMR genes mediating resistance to aminoglycosides (aac(6')-Iaa, aac(3)-VIa, aph(3')-Ia, aadA, 16S rrsD), ß-lactams (blaCTX-M-2), quinolones (parC), macrolides (acrB), tetracyclines (tet(A)), fosfomycin (fosA7) and sulfonamide (sul1). Interestingly, the mutation in parC T255S has never been reported among Salmonella Heidelberg strains. To our knowledge, this is the first report of a Salmonella enterica strain harbouring 16S rrsD 471G > A, acrB F28L and acrB L40P chromosomal point mutations. Three plasmid replicon types, ST2-IncHI2, ST2-IncHI2A and IncX1 were identified. Nine Salmonella Pathogenicity Islands and 98 virulence genes encoding virulence factors were identified associated with cell adhesion, invasion, intracellular survival and resistance to antimicrobial peptides. Although Salmonella Heidelberg E2 strain likely originated from poultry, cross-contamination during meat processing cannot be excluded. This study adds to our understanding of Salmonella Heidelberg transmission along the food-chain and informs ongoing regulatory discussions on Salmonella Heidelberg in poultry.

Listeria monocytogenes: health risk and a challenge for food processing establishments.

Listeria monocytogenes is a pathogenic bacterium present in several environments able to survive and proliferate in food processing plants, contaminating products that when ingested can lead to listeriosis. Worldwide, the bacterium has been isolated from foods of animal and plant origin and its occurrence in ready-to-eat foods is a challenge for food processing establishments. Serotypes 1/2a, 1/2b, 1/2c, and 4b related to 95% of listeriosis cases have been detected in different foods and presented resistance to common antibiotics such as tetracycline and penicillin. The analysis and dissemination of the presence of L. monocytogenes in different foods are essential to anchor control and prevention measures. In Brazil, despite the lack of official data on contamination by L. monocytogenes, some studies have reported the presence of bacteria in various foods and food processing environments. Thus, this review focuses on presenting the main characteristics of the L. monocytogenes, resistance to antimicrobial agents, and occurrence in several foods and countries from 2010 to 2020.

Isolamento de Salmonella na tecnologia de abate de suínos como subsídio para o sistema appcc / Salmonella isolation in a pig slaughtering technology as allowance for the system haccp / Aislamiento de Salmonella en la tecnología de matanza de porcinos como subsidio para el sistema appcc

A Salmonella pode estar presente em carcaças suínas ao final da tecnologia de abate, sendo que não existem procedimentos de inspeção especificamente direcionados para o controle desta bactéria, consideradas um risco potencial para a saúde pública. O objetivo do trabalho foi verificar a presença de Salmonella em carcaças suínas e caracterizar os pontos críticos de controle (PCCs) da tecnologia de abate como subsídio ao sistema APPCC. Foram realizados swabs de carcaças após a escaldagem/depilação, antes da evisceração, após evisceração e serragem da carcaça e após 24 horas de refrigeração, gerando 120 amostras (30 carcaças de cinco lotes). Isolou-se Salmonella em 53,3% dos PCs analisados, sendo 40% antes da eviscerarão e 30% após a escaldagem/depilação e evisceração/serragem. Nas carcaças resfriadas por 24 horas não foi isolada Salmonella. Os sorovares identificados foram Typhimurium (96,7 %) e Panama (3,22%). O isolamento de Salmonella reforça a necessidade de programas de monitoria da bactéria, desde as granjas até os abatedouros, enquanto o não isolamento nas carcaças resfriadas indica a importância da lavagem final e adequação da cadeia do frio, o que minimiza a contaminação pela intensificação das medidas de higiene e controle de pontos críticos para subsidiar o sistema APPCC...

Salmonella can be present in swine carcasses at the end of slaughtering and there is no specifically guided inspection procedure for the control of this bacterium, considered a potential risk for public health. The objective of this paper is to verify the presence of Salmonella in carcasses and to characterize the critical points of control (CPCs) of the slaughtering technology as a subsidy to the HACCP system. The carcasses were swabbed at different points during the slaughtering process, ant after 24 hours of refrigeration, generating 120 samples (30 carcasses from five different batches). Salmonella was isolated in 53.3% of the CPs analyzed, being 40% before evisceration and 30% after scalding/depilation and evisceration/ sawing. No Salmonella was isolated in the carcasses refrigerated for 24 hours. Typhimurium (96.7%) and Panama (3.22%) were the serovars identified. Salmonella isolation indicates the need of programs to monitor the bacterium from the farms to the slaughterhouse, while the non-isolation in the refrigerated carcasses shows the relevance of the cold chain, which minimizes the contamination by the intensification of hygiene measures and the control of critical points to subsidize the HACCP system...

La Salmonella puede estar presente en carcasas porcinas al final de la matanza, siendo que no existen procedimientos de inspección específicamente direccionados para el control de esta bacteria, consideradas un riesgo potencial a la salud pública. El objetivo del trabajo ha sido verificar la presencia de Salmonella en carcasas porcinas y caracterizar los puntos críticos de control (PCCs) en la tecnología de matanza como subsidio al sistema APPCC. Se han realizado swabs de carcasas tras escaldadura/depilación, antes de evisceración, después de la evisceración y serrín de la carcasa y después de 24 horas de refrigeración, generando 120 muestras (30 carcasas de cinco lotes) Se ha aislado Salmonella en 53,3% de los PCs analizados, siendo 40% antes de evisceración y 30% después de la escaldadura/depilación y evisceración/serrín. En las carcasas enfriadas por 24 horas no se ha aislado Salmonella. Los serovares identificados fueron Typhimurium (96,7%) y Panama (3,22%). El aislamiento de Salmonella refuerza la necesidad de programas de monitoria de la bacteria, desde las granjas hasta los mataderos, el no aislamiento en las carcasas enfriadas indica la importancia del lavado final y adecuación de la cadena del frío, lo que minimiza la contaminación por la intensificación de las medidas de higiene y control de puntos críticos para subsidiar el sistema APPCC...

Quantification of biofilm production on polystyrene by Listeria, Escherichia coli and Staphylococcus aureus isolated from a poultry slaughterhouse.

This study assessed biofilm formation on polystyrene by Staphylococcus aureus, Listeria monocytogenes, L. welshimeri and Escherichia coli, isolated from a slaughtering plant, grown on tryptic soy broth (TSB) using different glucose concentrations. The tested bacteria produced biofilm in at least one of the concentrations used, and some of them were strong biofilm producers.

Antimicrobial resistance in Campylobacter spp isolated from broiler flocks.

The aim of this study was to assess the antimicrobial susceptibility of 62 Campylobacter spp. strains obtained from broiler flocks using the agar diffusion method. The Campylobacter spp strains were isolated from 22 flocks aged between 3 and 5 weeks of life, isolated from cloacae swabs, stools and cecal droppings in the farm and from the carcass rinsing in the slaughterhouse. Campylobacter spp strains were tested on Mueller-Hilton (MH) agar (27 samples) and MH plus TTC agar (35 samples). The antimicrobial susceptibility test revealed a 62.5% resistance to at least one drug, especially to enrofloxacin (71%), neomycin (50%), lincomycin (50%), tetracycline (43%), penicillin (42%), ceftiofur (33%) amoxicillin (27%), spiramycin (20%), ampicillin (18%) and norfloxacin (14%), whereas a lower percentage of strains was resistant to erythromycin (10%) and doxycycline (10%). All strains were sensitive to gentamicin and lincomycin-spectinomycin and 80% of them to colistin. These results indicate that it is necessary to reduce the use of antimicrobials in veterinary and human medicine.

Antimicrobial resistance in Salmonella enteritidis strains isolated from broiler carcasses, food, human and poultry-related samples.

Antimicrobial resistance was investigated in 91 Salmonella enteritidis isolates from broiler carcasses, food, human and poultry-related samples originated from South of Brazil. A great proportion of resistant strains was found, 90.1% showing resistance to at least one antimicrobial drug. There was a high resistance to sulfonamides (75.8%) and nitrofurantoin (52.8%). Lower levels of resistance were found for tetracycline (15.4%), streptomycin (7.7%), nalidixic acid (7.7%), gentamicin (5.5%), norfloxacin (3.3%), trimethoprim (3.3%), cefalotin (2.2%), ampicillin (1.1%), and chloramphenicol (1.1%). Resistance to ciprofloxacin was not detected. A total of 51.6% of S. enteritidis strains were multiresistant (resistance to two or more antimicrobial agents) and 18 resistance patterns were found. The highest resistance was found in strains isolated from poultry-related samples, where all strains were resistant to at least one antimicrobial agent. No predominant resistance pattern was related to phage type in our isolates. The high number of antimicrobial resistant S. enteritidis found in Southern Brazil indicates the need for the prudent drugs uses to diminish the development and spread of antimicrobial resistance.

Phage types of Salmonella enteritidis isolated from clinical and food samples, and from broiler carcasses in southern Brazil.

272 isolates of Salmonella Enteritidis (111 isolated from frozen broiler chicken carcasses, 126 from human food and other biological materials involved in food poisoning outbreaks and 35 from different poultry materials) were selected for phage typing. From these, 111 were phage typed, 57.65% being classified as phage type 4, 32.43% as phage type 4a, 3.60% as phage type 6a and 0.90% as phage type 7, whereas 5.40% samples were not phage typeable. The predominance of phage type 4 is in agreement with the results published worldwide, and reinforces the need for studies related to the epidemiological meaning of these findings.