Escherichia coli O157:H7 has become a global public health and a food safety problem. Despite the implementation of control strategies that guarantee the safety in various products, outbreaks persist and new alternatives are necessary to reduce this pathogen along the food chain. Recently, our group isolated and characterised lytic bacteriophages against E. coli O157:H7 with potential to be used as biocontrol agents in food. To this end, phages need certain requirements to allow their manufacture and application. The aim of this study was to determine the physical stability and allergenic potential of free and microencapsulated (ME) bacteriophage cocktails against E. coli O157:H7. In vitro and in vivo studies were performed to determine phage survival under different pH, gastrointestinal conditions, temperature and UV light intensities. Results showed that the stability of ME phages was significantly (P<0.05) higher than free phages after ultraviolet irradiation, pH conditions between 3 to 7, and exposure to temperatures between at -80°C and 70°C. Both formulations were highly sensitive to very low pH in simulated gastric fluid, but stable in bile salts. In vivo studies in mice confirmed these phages passed through the gastrointestinal tract and were excreted in faeces. In silico, full-length alignment analysis showed that all phage proteins were negative for allergenic potential, but different predicting criteria classified seven phage proteins with a very low probability to be an allergen. In conclusion, these data demonstrated that microencapsulation provided a greater stability to phage formulation under stress conditions and assure a more suitable commercial formulation for the biological control of E. coli O157:H7.

Rapid degradation of fresh-cut papaya limits its marketability. Hydrothermal treatments in combination with a calcium dip, applied to whole fruit before slicing, and also the application of chitosan as a coating film, have been found to have very good results in maintaining the quality of fresh-cut fruits. Based on these considerations, the aim of this study was to evaluate the effect of hydrothermal treatment (HT; 49 °C, 25 min) containing calcium chloride (Ca; 1%, w/v) followed by dipping in chitosan (Chit; 1%, w/v, 3 min) on the physical, chemical, and microbial qualities of papaya slices stored at 5 °C for 10 d. Pulp color, firmness, ascorbic acid, total phenolics, β-carotene, and lycopene were evaluated every 2 d while the microbial quality (mesophilics, psychrophilics, molds, and yeasts) was evaluated every 5 d. Fruit treated with HT-Ca and HT-Ca + Chit showed better color and firmness retention than Control and Chit. Papaya slices treated with HT-Ca + Chit had higher nutritional content and lower microbial growth at the end of storage. The application of the HT-Ca + Chit could be used to reduce deterioration processes, maintaining physical, chemical, and microbial qualities and increasing the shelf life of fresh-cut papaya stored at 5 °C.

Abstract. Gnathostomiasis is now recognized as a zoonosis with a worldwide distribution. In the Americas, it is caused by the third-stage larvae of Gnathostoma binucleatum and in Asia mainly by G. spinigerum. The availability and preparation of specific antigens are among the main obstacles for developing reliable immunodiagnostic tests. In this study, six immunodominant peptides were identified and characterized from G. binucleatum, somatic antigens (AgS: 24, 32, and 40 kDa) and excretory-secretory antigens (AgES: 42, 44, and 56 kDa) by two-dimensional immunoblot analysis. Among those immunodominant peptides, two AgS spots were characterized by mass spectrometric analysis (32 kDa; pI 6.3 and 6.5) and identified as type 1 galectins. In accordance with this finding, a fraction of AgS exhibited affinity to lactose and displayed a 100% specificity and sensitivity for the diagnosis of human gnathostomiasis.

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T cell mediated response is involved in a protective immune response against experimental cysticercosis conferred by immunization with Taenia solium paramyosin (TPmy) to BALB/c mice. In this study, we analysed the TPmy amino acid sequence for predicted CD4+ T cells epitopes. Five different regions of this protein showed that the residues anchor to bind the I-Ad molecule, synthetic peptides containing these epitopes were evaluated for their ability to induce lymphoproliferative responses of spleen cells from TPmy immunized mice. Among them, Tp176 (amino acids 176-192 sequence DDLQRQMADANSAKSRL) was the immunodominant T cell epitope of TPmy. Delineation of this epitope should facilitate analysis of the role of CD4+ T cell response in experimental cysticercosis.