Regina Célia Santos Mendonça

Isolation, Characterization, and Application of Bacteriophages for Salmonella spp. Biocontrol in Pigs

Foodborne illness due to Salmonella-contaminated pork products is an important public health problem, causing significant economic losses worldwide. The use of bacteriophages is a potential intervention tool that has attracted interest for the control of foodborne pathogens. The objective of this study was to detect the presence of Salmonella in commercial pig farms and to isolate specific autochthonous bacteriophages against Salmonella Typhimurium, to characterize them and to evaluate their lytic capacity against Salmonella Typhimurium in vivo and in vitro. Salmonella was isolated on 50% (4/8) of the farms, with serotype Typhimurium being the most prevalent, detected in 48.2% of samples (13/27). The isolated Salmonella Typhimurium bacteriophages belong to the Podoviridae family, were active against serotypes Abony, Enteritidis, Typhi, and Typhimurium, but not against serotypes Arizonae, Cholerasuis, Gallinarum, and Pullorum. In in vitro tests, bacteriophage at 10(7) PFU/mL and 10(9) PFU/mL significantly reduced (p<0.05) Salmonella Typhimurium counts in 1.6 and 2.5 log10 colony-forming units (CFU)/mL, respectively, after 24 h. Before the in vivo treatment with bacteriophages, Salmonella was identified in 93.3% (28/30) of the fecal samples from the pigs inoculated with 10(6) CFU/mL, and only in 56.6% (17/30) after the treatment consisting of oral administration of the pool of the bacteriophages after the fasting period, simulating a common preslaughter practice. These results indicate that the pool of bacteriophages administered was capable of reducing the colonization of Salmonella in pigs.

The efficiency of electrocoagulation in treating wastewater from a dairy industry, Part I: Iron electrodes

Iron electrodes were used for electrocoagulation (EC) treatment of wastewater from a dairy plant. Electrolysis time, pH, current density and distance between electrodes were considered to assess the removal efficiency of chemical oxygen demand (COD), total solids (TS) and their fractions and turbidity. Samples were collected from the effluent of a dairy plant using a sampling methodology proportional to the flow. The treatments were applied according to design factorial of half fraction with two levels of treatments and three repetitions at the central point. The optimization of parameters for treating dairy industry effluent by electrocoagulation using iron electrodes showed that electric current application for 15 minutes, an initial sample pH close to neutral (pH 7.0) and a current density of 50 A . m−2 resulted in a significant reduction in COD by 58 %; removal of turbidity, suspended solids and volatile suspended solids by 95 %; and a final treated effluent pH of approximately 9.5. Negative consequences of the type of electrode used were the emergence of an undesirable color and an increase in the proportion of dissolved solids in the treated effluent.

Detection of exopolysaccharide production and biofilm-related genes in Staphylococcus spp. isolated from a poultry processing plant

Staphylococcus spp. can survive in biofilms for long periods of time, and they can be transferred from one point to another and cause environmental contamination in food processing. The aim of this study was to detect Staphylococcus strains isolated from a poultry processing plant by the presence of adhesion genes and the phenotypic production of exopolysaccharide. In the present study, the production of exopolysaccharide and the presence of adhesion genes in 65 strains of Staphylococcus spp. were evaluated. All strains of Staphylococcus spp. produced exopolysaccharide, as confirmed by formation of black and opaque colonies in Congo Red Agar. The variation of sucrose content was critical for the production of exopolysaccharide in Congo Red Agar since at low sucrose concentrations all strains presented a characteristic result, i.e., there was no exopolysaccharide production. The atl gene was found in all strains, and the ica A and icaD genes were found in 97% of them. The data obtained suggest that Staphylococcus spp. isolated from the poultry processing plant evaluated has a potential for biofilm formation. An efficient control of this microorganism in food processing environment is necessary as they may represent a potential risk to consumers.

Interference of Some Organic Substances and Microorganisms Adhered to Stainless Steel in ATP- bioluminescence Measurement

Adhesion of organic substances and microorganisms on stainless steel surface was evaluated. The log RLU measurement was affected at a lower or higher degree, by type or concentration of the organic substances (casein, lipid, sucrose and their combinations) adhered to surface. However, if the samples analyzed were from the food processing surfaces, they would have been considered to be under satisfactory hygienic conditions with log RLU 0.05) on ATP-bioluminescence measurements. However, the surfaces adhered with 2.9x103 DMC.cm-2 of B. subtilis spores and organic substances showed an increase in the log RLU measurement compared to surfaces containing only the organic substances.

Avaliação físico-química e microbiológica da adição de carne de frango mecanicamente separada em embutido fermentado

Taking into account the importance of the utilization by industry of mechanically deboned meat (MDM) to the poutry industry, the present research was conducted with the objective of evaluating the effect of its addition in a fermented sausage. Five formulations were studied, substituting hand deboned poultry meat by poultry MDM in the following proportions: 0, 9, 18, 27.5 and 37%. The results showed that the substitution of hand deboned poultry meat by poultry MDM did not affect the chemical composition of the sausage, improved lactic acid production, and did not impair de starter culture performance and the microbial quality of the product. However, the chemical stability was significantly impaired.

Campylobacter: An overview of cases, occurrence in food, contamination sources, and antimicrobial resistance in Brazil

ABSTRACT Campylobacter has been the most prevalent microorganism associated with foodborne gastroenteritis in developed countries in the last years. The consumption of contaminated chicken meat is the main source of campylobacteriosis in humans. However, in developing countries, Campylobacter has not been recognized as a food safety problem. Here, we provide an overview of studies focusing on occurrence of Campylobacter in Brazilian chicken processing chain, epidemiological data, contamination sources, antimicrobial resistance and fields where more studies are needed. Over the past 15 years, only five foodborne outbreaks involving 37 cases of campylobacteriosis were reported in Brazil. However, the occurrence of Campylobacter in samples of carcasses and chicken products was about 32.7%, and the microbial load ranged from <0.30 to 5.15 log10 CFU. This pathogen was also found in feces, caecum, intestine and cloaca of chicken (50.9%), chicken litter (65.4%), and water (13.7%). The most prevalent species identified in the studies were C. jejuni (80%) and C. coli (19.6%). In addition, high antimicrobial resistance rates were noted for cephalosporins (98.5–100%), quinolones (84.5%), and fluoroquinolones (77.6–82.8%). This review demonstrates that Campylobacter seems to be an important pathogen in the chicken processing chain and, consequently, for public health in Brazil.

Evaluation of microencapsulation of the UFV-AREG1 bacteriophage in alginate-Ca microcapsules using microfluidic devices

The indiscriminate use of antibiotics and the emergence of resistant microorganisms have become a major challenge for the food industry. The purpose of this work was to microencapsulate the bacteriophage UFV-AREG1 in a calcium alginate matrix using microfluidic devices and to study the viability and efficiency of retention. The microcapsules were added to gel of propylene glycol for use as an antimicrobial in the food industry. The technique showed the number of the phage encapsulation, yielding drops with an average 100-250μm of diameter, 82.1±2% retention efficiency and stability in the gel matrix for 21days. The gel added to the microencapsulated phage showed efficiency (not detectable on the surface) in reducing bacterial contamination on the surface at a similar level to antimicrobial chemicals (alcohol 70%). Therefore, it was possible to microencapsulate bacteriophages in alginate-Ca and apply the microcapsules in gels for use as sanitizers in the food industry.

Genome Sequence of the Enterohemorrhagic Escherichia coli Bacteriophage UFV-AREG1

ABSTRACT Here, we present the genome sequence of the Escherichia coli bacteriophage UFV-AREG1. This phage was isolated from cowshed wastewater and showed specificity for enterohemorrhagic E. coli O157:H7 (ATCC 43895), E. coli 0111 (CDC O11ab) and E. coli (ATCC 23229).

Microbiological Contamination in Foods and Beverages: Consequences and Alternatives in the Era of Microbial Resistance

Abstract Most foods constitute a rich source of nutrients for microbial development. Besides microorganisms, metabolic compounds, such as enzymes leads to contamination, spoilage, and degradation. Antimicrobials has been widely used to combat spoilage and pathogenic microorganism in several areas that involve human and animal health, including the food chain. Usually, problems in the supply and processing chain could change the environmental conditions of food and promote the growth of these microbial agents. Besides the food changes, some microbial agents can produce toxins and cause several illness to consumers. Several techniques are used in the food industry to detect the food-microbial contamination. Moreover, new methodologies are being developed to prevent and control these contaminants and their resistance to antimicrobials. This chapter will discuss the biochemistry, nutritional and sensorial effects caused by the microbial contamination of beverages, dairy, meat and egg products, fruits and vegetables, canned foods, and others. In addition, we will discuss the current and the future technologies used to prevent, detect, and control the food contamination and degradation.