Active Films of Cassava Starch Incorporated with Carvacrol Nanocapsules.

The synthesis of active films with natural antimicrobials from renewable sources offers an alternative to conventional non-biodegradable packaging and synthetic additives. This study aimed to develop cassava starch films with antimicrobial activity by incorporating either free carvacrol or chia mucilage nanocapsules loaded with carvacrol (CMNC) and assess their impact on the physical, mechanical, and barrier properties of the films, as well as their efficacy against foodborne pathogens. The addition of free carvacrol led to a reduction in mechanical properties due to its hydrophobic nature and limited interaction with the polymeric matrix. Conversely, CMNC enhanced elongation at break and reduced light transmission, with a more uniform distribution in the polymeric matrix. Films containing 8% carvacrol exhibited inhibitory effects against Salmonella and Listeria monocytogenes, further potentiated when encapsulated in chia mucilage nanocapsules. These findings suggest that such films hold promise as active packaging materials to inhibit bacterial growth, ensuring food safety and extending shelf life.

Carvacrol-loaded nanoemulsions produced with a natural emulsifier for lettuce sanitization.

Carvacrol is an antimicrobial agent that shows potential for eliminating microorganisms in vegetables, increasing food safety. However, intense odor and low water solubility of carvacrol are limiting factors for its application for fresh vegetables sanitization, which can be overcome by nanotechnology. Two different nanoemulsions containing carvacrol (11 mg/mL) were developed by probe sonication: carvacrol-saponin nanoemulsion (CNS) and carvacrol-polysorbate 80 nanoemulsion (CNP). Formulations presented appropriate droplet sizes (from 74.7 nm to 168.2 nm) and high carvacrol encapsulation efficiency (EE) (from 89.5 % to 91.5 %). CNS showed adequate droplet size distribution (PDI < 0.22) and high zeta potential values (around -30 mV) compared to CNP, with saponin chosen for the following experiments. Carvacrol nanoemulsions presented Bacterial Inactivation Concentration (BIC) against the Salmonella cocktail from 5.51 to 0.69 mg/mL and for the E. coli cocktail from 1.84 to 0.69 mg/mL. Among all tested nanoemulsions, CNS1 presented the lowest BIC (0.69 mg/mL) against both bacterial cocktails. Damage to bacterial cells in lettuce treated with nanoemulsion was confirmed by scanning electron microscopy. For lettuce sanitization, CNS1 showed a similar effect to unencapsulated carvacrol, with a high bacterial reduction (>3 log CFU/g) after lettuce immersion for 15 min at 2 × BIC. Using the same immersion time, the CNS1 (2 × BIC) demonstrated equal or better efficacy in reducing both tested bacterial cocktails (>3 log CFU/g) when compared to acetic acid (6.25 mg/mL), citric acid (25 mg/mL), and sodium hypochlorite solution (150 ppm). Lettuce immersed in CNS1 at both concentrations (BIC and 2 × BIC) did not change the color and texture of leaves, while the unencapsulated carvacrol at 2 × BIC darkened them and reduced their firmness. Consequently, carvacrol-saponin nanoemulsion (CNS1) proved to be a potential sanitizer for lettuce.

Labeling of ready-to-eat minimally processed vegetables sold in Brazil / Rotulagem de vegetais minimamente processados prontos para consumo comercializados no Brasil

Introduction: Ready-to-eat minimally processed vegetables (RTE-MPV) are vegetables subjected to several steps that modify their natural structure, while maintaining the same freshness and nutritional quality as the fresh produce. Since these products are sold in packages, they must be labeled, even though nutritional labeling is optional. Objective: The goal of this study was to assess the labeling aspects of several brands of RTE-MPV sold in Brazil, determining whether manufacturers adhered to the different types of food labeling legislation. Method: Photographic records of RTE-MPV packages were obtained in different regions of Brazil between October 2020 and August 2021, and labels were analyzed using a checklist that was prepared according to the different types of Brazilian food labeling legislation in force at the time of the study: RDC nº 259/2002, RDC nº 359/2003, RDC nº 360/2003 and Law nº 10,674/2003. Results: The labels of 288 RTE-MPV packages, belonging to 39 brands, were analyzed. Among these, 31 brands showed at least one aspect that was not in accordance with the legislation, such as the lack of information about place of origin, and the presence or absence of gluten. Although optional, most brands (38) adopted nutritional labeling, but the information was incomplete in ten of them. Conclusion: These data indicate that there are flaws in the labeling of RTE-MPV in Brazil, emphasizing the need for manufacturers to comply with the legislation. Moreover, the optional adoption of nutritional labeling by most brands is significantly important for consumers to have additional information about what they consume. (AU)

Introdução: Os vegetais minimamente processados (VMP) são submetidos a etapas que modificam sua estrutura natural, mantendo o frescor e qualidade nutricional dos produtos frescos. Por serem comercializados embalados, esses produtos devem ser rotulados, embora a rotulagem nutricional seja opcional. Objetivo: Este estudo analisou a rotulagem de diferentes marcas de VMP comercializados no Brasil, a fim de determinar a aderência dos produtores às legislações relativas à rotulagem de alimentos. Método: Foram obtidos registros fotográficos de embalagens VMP comercializados em diferentes regiões do Brasil entre outubro de 2020 e agosto de 2021, e os rótulos foram analisados por meio de um checklist elaborado com base nas legislações brasileiras de rotulagem de alimentos vigentes no período em que o estudo foi realizado: RDC nº 259/2002, RDC nº 359/2003, RDC nº 360/2003 e Lei nº 10.674/2003. Resultados: Foram analisados os rótulos de 288 embalagens de VMP, pertencentes a 39 marcas. Dentre essas, 31 marcas apresentaram pelo menos um item que não estava de acordo com as legislações de rotulagem vigentes, como falta de informação sobre o local de origem e a presença ou ausência de glúten. Apesar de opcional, a maioria das marcas (38) adotou a rotulagem nutricional, mas em dez delas as informações estavam incompletas. Conclusão: Esses dados indicam falhas na rotulagem de VMP no Brasil, enfatizando a necessidade das empresas de cumprirem essas regulamentações. Além disso, a adoção opcional da rotulagem nutricional pela maioria das marcas tem grande importância, pois fornece informações adicionais aos consumidores sobre os produtos que consomem. (AU)

Combining natural antimicrobials and nanotechnology for disinfecting food surfaces and control microbial biofilm formation.

The elimination of microbial surface contaminants is one of the most important steps in Good Manufacturing Practices in order to maintain food safety. This is usually achieved by detergents and chemical sanitizers, although an increased demand exists for the use of natural products for disinfection purposes. Several natural substances present antibacterial activity against the main foodborne pathogens, demonstrating great potential for use in the food industry. Some difficulties such as high volatility, residual taste and/or degradation by exposure to harsh processing conditions have been reported. Nanoparticle encapsulation appears as a strategy to protect bioactive compounds, maintaining their antimicrobial activity and providing controlled release as well. This article presents the potential of natural antimicrobials and their combination with nanotechnological strategies as an alternative for food surface disinfection and prevent microbial biofilm formation.

Desenvolvimento e caracterização de nanocápsulas poliméricas contendo carvacrol para inibição de Salmonella enteritidis / Development and characterization of polymeric nanocapsules containing carvacrol for inhibition from Salmonella enteritidis

Avaliou-se caracterização físico-química, ação bactericida e estabilidade de nanocápsulas poliméricas de Eudragit contendo carvacrol preparadas utilizando técnica de deposição interfacial do polímero pré-formado. As nanocápsulas apresentaram diâmetro médio de 146 nm, PDI de 0,181 e potencial zeta de + 23,44 mV e a concentração bactericida mínima necessária para inativar Salmonella Enteritidis foi de 0,331 mg/mL. A solução contendo nanocápsulas manteve suas características físico-químicas e atividade bactericida inalteradas durante os 45 dias do teste de estabilidade, demonstrando características promissoras para o desenvolvimento de um sanitizantes para uso em indústria produtora de ovos e frigorífico de aves.

Encapsulação de antimicrobianos naturais em nanolipossomas para inibição de bactérias causadoras de surtos alimentares / Encapsulation of natural antimicrobials in nanoliposomas for the inhibition of bacterials causing foodborne disease

Avaliou-se ação bactericida e caracterização físico-química de duas diferentes formulações de nanolipossomas preparados utilizando técnica de hidratação do filme lipídico. Nanolipossomas contendo carvacrol apresentaram diâmetro médio de 270,83 nm, PDI de 0,20 e potencial zeta de + 8,64 mV. Nanolipossomas contendo carvacrol e nisina apresentaram diâmetro médio de 205,25 nm, PDI de 0,31 e potencial zeta de - 22,48 mV. Para ambas formulações a concentração bactericida mínima foi de 3,53 mg/mL para Salmonella e 5,3 mg/mL para Escherichia coli e Staphylococcus aureus. Não ocorreu efeito sinérgico entre carvacrol e nisina, porém os nanolipossomas contendo carvacrol apresentaram ação bactericida contra os microrganismos testados, demonstrando potencial para sua utilização no desenvolvimento de um sanitizante para uso em indústrias de alimentos.

Antagonistic activity of Lactobacillus acidophilus LA10 against Salmonella enterica serovar Enteritidis SE86 in mice.

Salmonella enterica serovar Enteritidis is one of the main pathogens responsible for foodborne illness in Brazil. Probiotic bacteria can play a role in defense and recovery from enteropathogenic infections. In this study, the ability of Lactobacillus acidophilus LA10 to colonise and exert antagonistic effects in the gastrointestinal tract was tested before and during experimental infection in conventional mice contaminated with S. Enteritidis (SE86). A dose of 0.1 mL containing 10(8) viable cells of SE86 and L. acidophilus LA10 was orally administered by gavage to mice. The experiment was divided into groups. As a negative control, Group 1 was administered only sterile saline solution. As a positive control, Group 2 was administered only SE86. Group 3 was first administered SE86, and after 10 days, treated with L. acidophilus LA10. Group 4 was first administered L. acidophilus LA10, and after 10 days, challenged with SE86. The results demonstrated that a significant number of SE86 cells were able to colonize the gastrointestinal tract of mice, specifically in the colon and ileum. L. acidophilus LA10 demonstrated an antagonistic effect against SE86, with better results observed for Group 3 over Group 4. Thus, L. acidophilus LA10 shows potential antagonistic effects against S. Enteritidis SE86, especially if administered after infection.

Antagonistic activity of Lactobacillus acidophilus LA10 against Salmonella enterica serovar Enteritidis SE86 in mice

Salmonella enterica serovar Enteritidis is one of the main pathogens responsible for foodborne illness in Brazil. Probiotic bacteria can play a role in defense and recovery from enteropathogenic -infections. In this study, the ability of Lactobacillus acidophilus LA10 to colonise and exert anta-gonistic effects in the gastrointestinal tract was tested before and during experimental infection in conventional mice contaminated with S. Enteritidis (SE86). A dose of 0.1 mL containing 10(8) viable cells of SE86 and L. acidophilus LA10 was orally administered by gavage to mice. The experiment was divided into groups. As a negative control, Group 1 was administered only sterile saline solution. As a positive control, Group 2 was administered only SE86. Group 3 was first administered SE86, and after 10 days, treated with L. acidophilus LA10. Group 4 was first administered L. acidophilus LA10,and after 10 days, challenged with SE86.The results demonstrated that a significant number of SE86 cells were able to colonize the gastrointestinal tract of mice, specifically in the colon and ileum. L. acidophilus LA10 demonstrated an antagonistic effect against SE86, with better results observed for Group 3 over Group 4. Thus, L. acidophilus LA10 shows potential antagonistic effects against S. Enteritidis SE86, especially if administered after infection.

Inhibition of listeria monocytogenes in minas frescal cheese by free and nanovesicle-encapsulated nisin

The effectiveness of free and nanovesicle-encapsulated nisin to control Listeria monocytogenes in Minas Frescal cheese was investigated. Commercial nisin was encapsulated into liposomes of partially purified soy lecithin. Free (0.1 mg/mL and 0.25 mg/mL) and nanovesicle-encapsulated nisin (0.25 mg/mL) were applied onto the surface of cheese samples, and L. monocytogenes was inoculated before incubation at 6-8°C for 28 days. A bactericidal effect was observed with 0.25 mg/mL free nisin; a bacteriostatic effect was observed for liposome-encapsulated nisin and 0.1 mg/mL free nisin. Free nisin was more efficient than nisin-loaded liposomes in controlling L. monocytogenes. Possible reasons for this behavior, and also the significance of nisin to soft cheeses are discussed. Nisin acted as a suitable barrier within hurdle technology, potentially extending the shelf-life and safety of fresh cheeses.

Effect of liposome-encapsulated nisin and bacteriocin-like substance P34 on Listeria monocytogenes growth in Minas frescal cheese.

The efficacy of liposome-encapsulated nisin and bacteriocin-like substance (BLS) P34 to control growth of Listeria monocytogenes in Minas frescal cheese was investigated. Nisin and BLS P34 were encapsulated in partially purified soybean phosphatidylcholine (PC-1) and PC-1-cholesterol (7:3) liposomes. PC-1 nanovesicles were previously characterized. PC-1-cholesterol encapsulated nisin and BLS P34 presented, respectively, 218 nm and 158 nm diameters, zeta potential of -64 mV and -53 mV, and entrapment efficiency of 88.9% and 100%. All treatments reduced the population of L. monocytogenes compared to the control during 21 days of storage of Minas frescal cheese at 7°C. However, nisin and BLS P34 encapsulated in PC-1-cholesterol liposomes were less efficient in controlling L. monocytogenes growth in comparison with free and PC-1 liposome-encapsulated bacteriocins. The highest inhibitory effect was observed for nisin and BLS P34 encapsulated in PC-1 liposomes after 10 days of storage of the product. The encapsulation of bacteriocins in liposomes of partially purified soybean phosphatidylcholine may be a promising technology for the control of foodborne pathogens in cheeses.

Inhibition of Listeria monocytogenes in minas frescal cheese by free and nanovesicle-encapsulated nisin.

The effectiveness of free and nanovesicle-encapsulated nisin to control Listeria monocytogenes in Minas Frescal cheese was investigated. Commercial nisin was encapsulated into liposomes of partially purified soy lecithin. Free (0.1 mg/mL and 0.25 mg/mL) and nanovesicle-encapsulated nisin (0.25 mg/mL) were applied onto the surface of cheese samples, and L. monocytogenes was inoculated before incubation at 6-8°C for 28 days. A bactericidal effect was observed with 0.25 mg/mL free nisin; a bacteriostatic effect was observed for liposome-encapsulated nisin and 0.1 mg/mL free nisin. Free nisin was more efficient than nisin-loaded liposomes in controlling L. monocytogenes. Possible reasons for this behavior, and also the significance of nisin to soft cheeses are discussed. Nisin acted as a suitable barrier within hurdle technology, potentially extending the shelf-life and safety of fresh cheeses.

Perfil de resistência a antimicrobianos de cepas Pseudomonas aeruginosa isoladas de ralos e pias de enfermarias hospitalares em Santa Catarina, Brasil / Antimicrobial resistance profile of Pseudomonas aeruginosa strains isolated from sinks and drains in hospital wards in Santa Catarina, Brazil

Pseudomonas aeruginosa é um micro-organismo oportunista que contribui para ocorrência de infecções hospitalares. A ocorrência desta bactéria foi investigada em 104 amostras isoladas de pias e ralos de enfermarias de dois hospitais de Santa Catarina. P. aeruginosa foi identificada em 47% das amostras. A suscetibilidade a antimicrobianos foi avaliada através do teste de difusão em agar, segundo recomendações do Commitee for Clinical Laboratory Standards (CLSI). Observou-se elevada resistência para cefalotina(100%), seguida pelo imipenem (34,7%), gentamicina (26,5%) e ceftriaxona (18,3%). As linhagens isoladas apresentaram elevadasensibilidade à ciprofloxacina e norfloxacina, 100% e 95,9%, respectivamente. Cerca de 40% das linhagens apresentaram multirresistência. Os resultados de resistência foram correlacionados com os principais antimicrobianos utilizados nos hospitais. Esses resultados indicam que pias e ralos em enfermarias hospitalares representam um risco potencial para a saúde pública, por apresentarem bactérias com elevada resistência a antimicrobianos, demonstrando a necessidade do uso racional de antibióticos nos hospitais edesinfecção adequada desses locais

Pseudomonas aeruginosa is an opportunistic microorganism that contribute to the occurrence of hospital infections. The occurrence of this bacterium was investigated in 104 samples isolated from sinks and drains of two hospitals in Santa Catarina. P. aeruginosa was identified in 47% of the samples. The antimicrobial susceptibility was evaluated by the agar diffusiontest, according to recommendations of the Commitee for Clinical Laboratory Standard (CLSI). It was observed a high resistance to cefalotin (100%), followed by imipenem (34.7%), gentamycin (26.5%) and ceftriaxone (18.3%). The strains showed elevatedsensitivity to ciprofloxacin and norfloxacin, 100% and 95.9%, respectively. Multidrug resistance was observed in about 40% of strains. The results for antimicrobial resistance correlate with the major antimicrobial agents used in the hospitals. Theseresults indicate that sinks and drains in hospital wards represent a potential hazard to public health, to present potentially dangerous bacteria with resistance to antibiotics, demonstrating the need for rational use of antibiotics in hospitals and disinfection of those locations

Adhesion and biocides inactivation of Salmonella on stainless steel and polyethylene

The adhesion of Salmonella (S.) strains to stainless steel and polyethylene and their inactivation by biocides used in food industry was investigated. Coupons of stainless steel and polyethylene were immersed in bacterial suspensions of S. Enteritidis, S. Typhimurium, and S. Bredeney during 15, 30, and 60 minutes, and submitted to different concentrations of peracetic acid (PAA), sodium hypochlorite (NaOCl), and quaternary ammonium (Quat) sanitizers. Hydrophobicity of the surfaces was evaluated by contact angle measurements using the sessile drop method and bacterial adhesion was accompanied through bacterial counts and scanning electron microscopy (SEM). Results indicated that the three serovars of Salmonella presented similar adhesion to both materials (5.0 to 6.5 log cfu cm-2). The time of exposure did not influence the counts of adhered cells on both surfaces, however SEM revealed larger clusters of S. Enteritidis on both materials, not found for the other serovars. S. Enteritidis presented lower sessile drop angle on polyethylene, indicating hydrophilic properties of this material. The biocides were not able to inactivate all the microorganisms adhered on both surfaces. At least 1 log cfu cm-2 of all serovars tested remained viable after the exposure to different biocide concentrations. In general, higher counts of survivors were observed on polyethylene disinfected with different concentrations of biocides. S. Bredeney e S. Typhimurium were more resistant than S. Enteritidis to PAA, whilst S. Enteritidis presented smaller reduction rates to NaOCl. This last biocide was able to reduce Salmonella counts in approximately 3.0 to 4.0 log cm-2. When adhered to polyethylene, the serovars S. Typhimurium and S. Enteritidis were more resistant to Quat than S. Bredeney in all concentrations tested, and the numbers of S. Enteritidis remained almost unaltered. On stainless steel disinfected by Quat, S. Bredeney presented higher numbers of survivors.

Avaliação da resistência de Salmonella à ação de desinfetantes ácido peracético, quaternário de amônio e hipoclorito de sódio / The resistance of Salmonella strains to the biocides peracetic acid, quaternary ammonium and sodium hypochlorite

Este estudo avaliou a resistência de três cepas de Salmonella frente aos desinfetantes ácido peracético, quaternário de amônio e hipoclorito de sódio. S. Enteritidis (SE86), responsável por mais de 90% dos surtos alimentares ocorridos no Rio Grande do Sul (RS), foi comparada com S. Typhimurium e S. Bredeney, ambas não envolvidas na ocorrência de salmonelose. A resistência aos desinfetantes foi avaliada por meio de teste de suspensão, conforme preconizado pelo Ministério da Agricultura, Pecuária e Abastecimento. Todos os desinfetantes avaliados, nas concentrações indicadas pelos fabricantes, foram capazes de inativar as três cepas de Salmonella, entretanto, SE86 apresentou maior resistência ao hipoclorito de sódio a 400 ppm, além de ser a única cepa bacteriana capaz de sobreviver por até 15 minutos de exposição a 200 ppm desse desinfetante. Uma vez que o hipoclorito de sódio, nestas condições, é empregado com frequência como agente de desinfecção em indústrias de alimentos e serviços de alimentação, as características acima mencionadas podem contribuir para que esse microrganismo seja responsável pelos surtos de salmoneloses ocorridos no RS. Em função da importância desses micro-organismos como agentes patogênicos alimentares, cuidados especiais devem ser tomados nos processos de desinfecção e contaminação cruzada por Salmonella.

The resistance of Salmonella strains to the biocides peracetic acid, quaternary ammonium and sodiumhypochlorite was assessed. S. Enteritidis (SE86), which is responsible for more than 90% of food-borneoutbreaks occurred in Rio Grande do Sul (RS) was compared to S. Typhimurium and S. Bredeney, bothnot related to salmonellosis. The bacterial resistance to biocides was evaluated using the suspension test asrecommended by The Brazilian Agriculture Ministry. The three biocides were able to inactivate all of themicroorganisms tested, when the concentrations indicated by the manufacturers were used. However, SE86was resistant to 400 ppm sodium hypochlorite, and survived for up to 15 minutes of exposure to 200 ppmof this biocide, which was not demonstrated by the other bacteria strains. Since the sodium hypochlorite,at such concentration and time of exposure, is frequently used at food industries and food services, andowing to the above cited resistance characteristic, this condition could be contributing for the SE86 withfood-borne salmonellosis outbreak occurred in RS. In view of the importance of these microorganismsas alimentary pathogens, special cares in the food disinfection processes and cross-contamination withSalmonella must be taken.

Adhesion and biocides inactivation of Salmonella on stainless steel and polyethylene.

The adhesion of Salmonella (S.) strains to stainless steel and polyethylene and their inactivation by biocides used in food industry was investigated. Coupons of stainless steel and polyethylene were immersed in bacterial suspensions of S. Enteritidis, S. Typhimurium, and S. Bredeney during 15, 30, and 60 minutes, and submitted to different concentrations of peracetic acid (PAA), sodium hypochlorite (NaOCl), and quaternary ammonium (Quat) sanitizers. Hydrophobicity of the surfaces was evaluated by contact angle measurements using the sessile drop method and bacterial adhesion was accompanied through bacterial counts and scanning electron microscopy (SEM). Results indicated that the three serovars of Salmonella presented similar adhesion to both materials (5.0 to 6.5 log cfu cm(-2)). The time of exposure did not influence the counts of adhered cells on both surfaces, however SEM revealed larger clusters of S. Enteritidis on both materials, not found for the other serovars. S. Enteritidis presented lower sessile drop angle on polyethylene, indicating hydrophilic properties of this material. The biocides were not able to inactivate all the microorganisms adhered on both surfaces. At least 1 log cfu cm(-2) of all serovars tested remained viable after the exposure to different biocide concentrations. In general, higher counts of survivors were observed on polyethylene disinfected with different concentrations of biocides. S. Bredeney e S. Typhimurium were more resistant than S. Enteritidis to PAA, whilst S. Enteritidis presented smaller reduction rates to NaOCl. This last biocide was able to reduce Salmonella counts in approximately 3.0 to 4.0 log cm(-2). When adhered to polyethylene, the serovars S. Typhimurium and S. Enteritidis were more resistant to Quat than S. Bredeney in all concentrations tested, and the numbers of S. Enteritidis remained almost unaltered. On stainless steel disinfected by Quat, S. Bredeney presented higher numbers of survivors.

Contaminação bacteriológica de águas subterrâneas da região oeste de Santa Catarina, Brasil / Bacteriological contamination of groundwater of the western area of Santa Catarina, Brazil

O objetivo do estudo foi avaliar a qualidade bacteriológica de águas subterrâneas da região oeste do Estado de Santa Catarina, onde é comum a utilização de poços comunitários ou particulares. As amostras foram avaliadas pela técnica de fermentação em tubos múltiplos de acordo com a metodologia descrita no American Public Health Association e segundo a instrução normativa 62 de 26 de agosto de 2003, do Ministério da Agricultura Pecuária e Abastecimento. Além disso, foi realizado levantamento de dados por meio de um questionário, cujas questões foram respondidas pelo responsável pelo respectivo poço. Das 212 amostras de água analisadas, 161 (75,94%) estavam impróprias para o consumo humano, conforme a Portaria 518/2004 do Ministério da Saúde. Apesar dos altos índices de contaminação bacteriológica nas amostras avaliadas, a maioria dos consumidores julga essa água de boa qualidade e por isso, apenas 10% dos usuários costumam filtrar e 8% fervem a água antes do consumo. Portanto, torna-se necessário a adoção de medidas preventivas e o tratamento das águas já comprometidas.