Surface conditioning with bacteriophages reduces biofilm formation of Salmonella Heidelberg.

Salmonella remains one of the most common foodborne pathogens worldwide, and its resistance to antimicrobials has increased considerably over the years. In this context, was evaluated the action of three bacteriophages isolated or combined in inhibiting the adhesion and removal of Salmonella Heidelberg biofilm on a polystyrene surface. The bacteriophages UPF_BP1, UPF_BP2, UPF_BP3 and a pool of them were used for biocontrol of Salmonella Heidelberg biofilms on polystyrene surface in the action times of 3, 6 and 9 h. Individual and combined phages exhibited reductions in Salmonella Heidelberg adhesion of up to 83.4% and up to 64.0% in removal of preformed biofilm. The use of synergistic combinations between the phages is the most indicated option due to its potential to reduce biofilms. The use of the bacteriophage pool in surface conditioning is an alternative in the control of Salmonella Heidelberg biofilms.

Antimicrobial activity of essential oils and natural plant extracts against Listeria monocytogenes in a dry-cured ham-based model.

BACKGROUND: Listeria monocytogenes is a widespread common contaminant in food production facilities during preparation, storage, and distribution, and minimally processed ready-to-eat products are considered at high risk of contamination by this bacterium. Increased antibiotic resistance has led researchers to search for plant-based natural alternatives to control pathogenic microorganisms. Among these products, essential oils and plant extracts have previously shown antimicrobial activity and are possible alternatives to manage food pathogens. In this study, commercial essential oils (cinnamon, clove, oregano, ginger, and thyme) and plant extracts (pomegranate, acorn, olive, strawberry tree, and dog rose) were tested against L. monocytogenes in a dry-cured ham-based model. RESULTS: Essential oils and plant extracts were screened by agar diffusion and minimum inhibitory concentration for anti-L. monocytogenes activity. Cinnamon, pomegranate, and strawberry trees returned the strongest results and were therefore evaluated in a dry-cured ham-based medium assay with water activity of 0.93 or 0.95. The 10% essential oil of cinnamon was capable of completely inhibiting bacterial growth, while strawberry tree and pomegranate extract also showed antilisterial activity (P > 0.05). Water activity influenced the bacterial count of L. monocytogenes in a dry-cured ham-based medium. CONCLUSIONS: There was a reduction in L. monocytogenes with the application of cinnamon essential oil but, because of the negative sensory impact of this particular compound in meat products, we suggest the use of pomegranate or strawberry tree for the biocontrol of Listeria in ready-to-eat products. © 2021 Society of Chemical Industry.

Ammonia gas for bacterial control in poultry litter / Gás amônia para controle bacteriano em cama aviária

The current techniques used in the disinfection of reused poultry litter, such as lime addition, windrowing and plastic cover on the surface, do not guarantee the elimination of pathogenic microorganisms, causing damage to the environment and animal health. Gram negative bacteria, i.e., Salmonella and Escherichia coli, can be transmitted from one batch to another through reused litter, causing health damage to broilers and humans that consume food contaminated by these agents. Our study assessed the effectiveness of the methods plastic cover on the surface (PCS) and plastic cover on the surface with ammonia gas injection (PCSAI) in the control of Gram negative bacteria. The results obtained, both in laboratory conditions (Experiment 1) and in the field (Experiment 2), demonstrate that the method PCSAI with 0.22% ammonia gas had a significant reduction (P<0.05) of Gram negative bacteria in the period of 48 hours This new methodology for disinfecting poultry litter will allow its reuse in a practical and safe way, improving the preservation of the environment, of the health of broilers and consumers of poultry products.

O reaproveitamento de camas aviárias na criação de frangos de corte é uma prática muito utilizada no Brasil. Essa prática reduz custos de produção e contribui na conservação do meio ambiente. As técnicas atuais utilizadas na desinfecção de camas aviárias reaproveitadas, como adição de cal, enleiramento e lona na superfície, não garantem a eliminação de microrganismos patogênicos porque não geram quantidade suficiente de amônia. O gás amônia, em concentrações elevadas, tem efeito biocida. Bactérias Gram negativas, como as Salmonelas e Escherichia coli, podem ser transmitidas de um lote para outro através do reaproveitamento da cama, ocasionando prejuízos para a saúde das aves e dos humanos que consomem alimentos contaminados por estes agentes. Este trabalho avaliou a eficácia do método lona na superfície com injeção de gás amônia no controle de microrganismos Gram negativos. Os resultados obtidos demostraram que esse método controlou os microrganismos Gram negativos num período de 48 horas em camas de frangos de corte reaproveitadas. Assim, essa nova metodologia de desinfecção de camas de aviário permitirá sua reutilização de forma prática e segura, melhorando a saúde das aves e dos consumidores dos produtos avícolas.

Ammonia gas for bacterial control in poultry litter

ABSTRACT: The current techniques used in the disinfection of reused poultry litter, such as lime addition, windrowing and plastic cover on the surface, do not guarantee the elimination of pathogenic microorganisms, causing damage to the environment and animal health. Gram negative bacteria, i.e., Salmonella and Escherichia coli, can be transmitted from one batch to another through reused litter, causing health damage to broilers and humans that consume food contaminated by these agents. Our study assessed the effectiveness of the methods plastic cover on the surface (PCS) and plastic cover on the surface with ammonia gas injection (PCSAI) in the control of Gram negative bacteria. The results obtained, both in laboratory conditions (Experiment 1) and in the field (Experiment 2), demonstrate that the method PCSAI with 0.22% ammonia gas had a significant reduction (P 0.05) of Gram negative bacteria in the period of 48 hours This new methodology for disinfecting poultry litter will allow its reuse in a practical and safe way, improving the preservation of the environment, of the health of broilers and consumers of poultry products.

RESUMO: O reaproveitamento de camas aviárias na criação de frangos de corte é uma prática muito utilizada no Brasil. Essa prática reduz custos de produção e contribui na conservação do meio ambiente. As técnicas atuais utilizadas na desinfecção de camas aviárias reaproveitadas, como adição de cal, enleiramento e lona na superfície, não garantem a eliminação de microrganismos patogênicos porque não geram quantidade suficiente de amônia. O gás amônia, em concentrações elevadas, tem efeito biocida. Bactérias Gram negativas, como as Salmonelas e Escherichia coli, podem ser transmitidas de um lote para outro através do reaproveitamento da cama, ocasionando prejuízos para a saúde das aves e dos humanos que consomem alimentos contaminados por estes agentes. Este trabalho avaliou a eficácia do método lona na superfície com injeção de gás amônia no controle de microrganismos Gram negativos. Os resultados obtidos demostraram que esse método controlou os microrganismos Gram negativos num período de 48 horas em camas de frangos de corte reaproveitadas. Assim, essa nova metodologia de desinfecção de camas de aviário permitirá sua reutilização de forma prática e segura, melhorando a saúde das aves e dos consumidores dos produtos avícolas.

Research Note: The use of ammonia gas for Salmonella control in poultry litters.

A new poultry litter disinfection methodology against pathogenic Salmonella spp. serovars using gaseous ammonia is proposed in this study. In the laboratory, the poultry litter was disposed into plastic containers and experimentally contaminated with 3 Salmonella spp. serovars separately. Positive and negative control groups were tested. With a system of hoses, 1% gaseous ammonia was injected into the containers in cycles for 48 h. Samples of the poultry litter were collected and submitted to bacteriological analysis. For the second part, we selected a broiler poultry farm with positive litters for Salmonella heidelberg in 2 houses. The littler was treated by gaseous ammonia in a concentration of 2,411 ppm and wrapped with a plastic cover for 48 h during the sanitary break. After the treatment, a new broiler batch was housedand swab samples were collected in the 25-day-old. After the action of the gaseous compound, there was no reisolation of the serovars, and the batches housed on the ammonia-treated litter no longer showed positive results for Salmonella. The total elimination of the pathogenic microorganisms by the new method suggests that the controlled use of ammonia gas in poultry litter may represent a viable disinfection technique.

Alphitobiusdiaperinus control and physicochemical study of poultry litters treated with quicklime and shallow fermentation.

Poultry litter reuse in Brazil is a common practice to reduce broiler production costs. Quicklime and shallow fermentation treatments are methods used to reduce microbial contamination and infestation of insects such as Alphitobius diaperinus (Panzer). The aim of this study was to evaluate the physicochemical parameters of reused poultry litter to better characterize the effects of quicklime and shallow fermentation on Salmonella and A. diaperinus control. Ammonia and humidity concentrations significantly increased on the litter treated with shallow fermentation and pH when treated with virgin and hydrated quicklime. For A. diaperinus control, shallow fermentation with 2 and 3 L of water and 3 L plus 600g of quicklime/m2 eliminated 100% of the insects. Results of assessed physicochemical parameters indicated that the treatments with quicklime and shallow fermentation are inefficient to control Salmonella spp. because they do not reach the indexes required for this pathogen elimination, mainly ammonia and pH. Ammonia index produced by microbial fermentation in shallow fermentation treatment eliminates A. diaperinus.

Detection and quantification of Campylobacter spp. in Brazilian poultry processing plants.

INTRODUCTION: Campylobacteriosis is considered the most common bacteria-caused human gastroenteritis in the world. Poultry is a major reservoir of Campylobacter. Human infection may occur by consumption of raw and undercooked poultry or by contamination of other foods by these items. The aim of this study was to assess the prevalence of Campylobacter spp. in poultry processing plants with conventional culture method and real-time PCR. METHODOLOGY: A total of 108 poultry processing plant samples were collected to test with conventional microbiology and qPCR. Sampling included cloacal swabs, swabs of transport crates (before and after the cleaning and disinfection process) and carcasses (after the chiller, cooled at 4°C and frozen at -12°C). RESULTS: Positivity in cloacal swabs indicated that poultry arrived contaminated at the slaughterhouse. Contamination in transport cages was substantially increased after the cleaning process, indicating that the process was ineffective. The detection of Campylobacter on carcasses was higher than that on cloacal swabs, which could indicate cross-contamination during the slaughtering process. Conventional microbiology and molecular methods revealed a prevalence of 69.4% and 43.5%, respectively. Lower detection by qPCR can be attributed to the high specificity of the kit and to biological components that could inhibit PCR reactions. CONCLUSIONS: Our results indicate that poultry arrive contaminated at the slaughterhouse and that contamination can increase during the slaughtering process due to cross-contamination. The isolation of Campylobacter in cooled and frozen carcasses corroborates the bacterial survival even at temperatures considered limiting to bacterial growth which are routinely used for food preservation.

Antimicrobial and Disinfectant Susceptibility of Salmonella Serotypes Isolated from Swine Slaughterhouses.

Salmonella remains one of the most common foodborne pathogens worldwide, and its resistance to antimicrobials and disinfectants has increased considerably over the years. Thus, monitoring its resistance to products commonly used in swine production is indispensable for the development of strategies to reduce the occurrence of bacterial resistance. In this context, our aim was to detect Salmonella at different points in swine slaughterhouses, identify the main serotypes, and evaluate their resistance to disinfectants and antimicrobials used in swine production. Salmonella at the processing plants was detected by conventional microbiology. Salmonella strains were tested for susceptibility to peracetic acid (0.5% and 1%), quaternary ammonium (0.5%), and seven antimicrobials. Twenty-eight percent of the samples were positive for Salmonella, with the most identified serotypes being Salmonella Derby, Salmonella Typhimurium, and monophasic Salmonella Typhimurium. All tested strains were susceptible to both concentrations of peracetic acid, but only 28% were susceptible to quaternary ammonium. Sixteen percent of the strains were susceptible to all tested antimicrobials. Only enrofloxacin was efficient in inhibiting the growth of all strains. The highest number of non-susceptible strains was to amoxicillin, followed by chloramphenicol, florfenicol, and doxycycline. Thirty-six percent of the strains were classified as multidrug-resistant. Salmonella were detected in all slaughtering processes, and important serotypes were recovered, including Salmonella Typhimurium, Salmonella Derby, monophasic Salmonella Typhimurium, and Salmonella Infantis. We observed high rates of resistance to quaternary ammonium and to important antimicrobial agents. Salmonella Typhimurium and Salmonella Infantis were the most resistant serotypes.

Fluoroquinolone resistance in Campylobacter jejuni and Campylobacter coli from poultry and human samples assessed by PCR-restriction fragment length polymorphism assay.

The objective of this study was to determine fluoroquinolone resistance in Campylobacter spp from poultry and human isolates. Forty-one Campylobacter jejuni isolates (30 of poultry origin and 11 of human origin) and 11 Campylobacter coli isolates (10 of human origin and 1 of poultry origin) were examined for ciprofloxacin, norfloxacin, and nalidixic acid resistance using the minimal inhibitory concentration (MIC) method. Thereafter, the isolates were analyzed by PCR-Restriction Fragment Length Polymorphism (RFLP) assay for detection of Thr-86 mutation. Finally, DNA sequencing was performed for confirmation of gyrA gene mutation. A complete correlation was observed between MICs, PCR-RFLP assay, and sequencing. The results revealed high quinolone resistance rates for C. jejuni (100%) and C. coli (100%) isolates obtained from poultry and moderate resistance for C. jejuni (9.1%) and C. coli (40%) samples of human origin. A mutation in codon 86 of the gyrA gene with a Thr-to-Ile substitution is reported to be the main cause of high resistance to quinolones. This mutation can be analyzed by PCR-RFLP assay, which has been proven to be a simple and fast method for the detection of fluoroquinolone resistance in Campylobacter spp.

Avaliação in vitro de clorexidina, amônia quaternária e ácido peracético frente a amostras de Salmonella Heidelberg isoladas de abatedouro avícola em 2005 e 2009 / In vitro evaluation of chlorhexidine, quaternary ammonium and peracetic acid against Salmonella Heidelberg isolated from poultry slaughterhouse in 2005 and 2009

Objetivou-se avaliar a ação de três princípios ativos rotineiramente utilizados na higienização de abatedouros avícolas frente a amostras de Salmonella Heidelberg isoladas em diferentes pontos da tecnologia de abate de um mesmo frigorífico. Foram testadas 20 amostras de S. Heidelberg (14 isoladas em 2005 e seis em 2009) frente a clorexidina (0,5%), amônia quaternária (0,5%) e ácido peracético (1%) nos tempos de contato de 5, 10, 15 e 20 minutos. Todas as amostras foram sensíveis ao ácido peracético 1% em todos os tempos testados. Observou-se que 100% das amostras isoladas em 2005 foram sensíveis a amônia quaternária enquanto que as isoladas em 2009 apresentaram 33% de resistência com 5 minutos de contato e 16,6% com 10 minutos de contato. Com relação à clorexidina, 25% dos isolados em 2005 mostraram-se resistentes após 5 minutos de contato enquanto que 33% das amostras isoladas em 2009 foram resistentes neste tempo e 17% no tempo de 10 minutos de contato. Pode-se concluir que o ácido peracético teve ação in vitro sobre as amostras isoladas em 2005 e 2009, enquanto que a clorexidina e a amônia quaternária tiveram sua ação reduzida frente às amostras de 2009, indicando a progressão da resistência bacteriana frente a estes sanitizantes e a necessidade de testes periódicos e rotação de princípios ativos nos programas de higienização dos frigoríficos.

The objective of this investigation was to evaluate the in vitro sensibility of Salmonella Heidelberg to three commercially available disinfectants used for sanitization in poultry slaughterhouses. A total of 20 S. Heidelberg were tested (14 isolated in 2005 and six in 2009), and as active ingredients were used chlorhexidine (0.5%), quaternary ammonium (0.5 %) and peracetic acid (1%) at contact intervals of 5, 10, 15 e 20 minutes. All isolates were found to be sensitive to peracetic acid at four specific contact intervals. One hundred percent of S. Heidelberg isolated in 2005 was found to be sensitive to quaternary ammonium, while 33% of 2009 isolates were resistant at a 5-minute contact interval and 16.6% at 10-minutes. With respect to chlorhexidine, 25% of the 2005 isolates were resistant at a 5-minute contact interval, 33% of the 2009 isolates were resistant with the same time, and 17% at a 10-minute contact interval. It can be concluded that the highest disinfectant activity in vitro was found to be with peracetic acid for S. Heidelberg isolates in 2005 and 2009, whereas chlorhexidine and quaternary ammonium had a reduced action against 2009 isolates, indicating the progression of bacterial resistance against these sanitizers and the need for periodic evaluation and rotation of active principles for sanitization.