This study investigated the physicochemical, instrumental and bacterial parameters of tilapia fillets subjected to oxygen-scavenger packaging, alone or in combination with UV-C radiation at two doses (0.102 and 0.301 J/cm2), stored at 4 ± 1 °C for 23 days. The oxygen scavenger, both UV-C doses, and the oxygen scavenger combined with UV-C, independently of the dose, extended the shelf life in 5, 6 and 7 days, respectively, by decreasing the bacterial growth rate and the formation of degradation compounds (e.g., TVB-N and ammonia). Oxygen-scavenger packaging, alone or in combination with UV-C at 0.102 J/cm2 and 0.301 J/cm2 showed lower amounts of free amino acids (FAA; 34.39, 34.49 and 34.50 mg L-lysine/kg fish tissue, 3.63, 3.57 and 3.61 mg L- ornithine/kg fish tissue, 27.52, 27.63 and 27.67 mg L-arginine/kg fish tissue), biogenic amines (BA; 3.81, 3.87 and 3.89 mg cadaverine/kg fish tissue, 12.88, 12.91 and 12.86 mg putrescine/kg fish tissue, 2.41, 2.44 and 2.47 mg spermidine/kg fish tissue), redness (2.53, 2.55 and 2.59), yellowness (6.65, 6.69 and 6.72), lipid oxidation (1.52, 1.53 and 1.58 mg malondialdehyde/kg fish tissue) and protein oxidation (5.06, 5.11 and 5.18 nmol carbonyls/mg protein), with higher hardness (3273.41, 2652.98 and 2687.57 g) than control (air packaging; 41.97 mg L-lysine/kg fish tissue, 4.83 mg L- ornithine/kg fish tissue, 37.33 mg L-arginine/kg fish tissue, 4.82 mg cadaverine/kg fish tissue, 16.56 mg putrescine/kg fish tissue, 3.21 mg spermidine/kg fish tissue, 4.26 of redness, 8.17 of yellowness, 2.88 mg malondialdehyde/kg fish tissue, 9.44 nmol carbonyls/mg protein and 2092.58 g of hardness), respectively, on day 13 of storage when the control fillets were unfit for consumption (7 log CFU/g) (p < 0.05). However, in the same day of storage, both UV-C doses had similar values for BA (p > 0.05), higher amounts of FAA (44.28 and 44.13 mg L-lysine/kg fish tissue, 5.16 and 5.12 mg L- ornithine/kg fish tissue, 40.20 and 40.28 mg L-arginine/kg fish tissue), redness (4.86 and 5.33), yellowness (9.32 and 10.01), lipid oxidation (3.09 and 3.52 mg malondialdehyde/kg fish tissue) and protein oxidation (10.27 and 11.93 nmol carbonyls/mg protein), as well as lower hardness (1877.54 and 1767.39 g), respectively, than control fillets (p < 0.05). The combined preservation methods were the most effective in extending the shelf life and prolonging the physicochemical quality of the refrigerated tilapia fillets and the O2 scavenger proved to be a potential alternative to prevent the negative changes induced by both UV-C doses.

Historically, Escherichia coli is among the most studied organisms and serves as the basis for understanding many fundamental biochemical and genetic concepts. In addition, it displays 9 pathogenesis groups, with the Shiga toxin-producing (STEC) group being the main representative regarding foodborne pathogenesis. Its typical characteristic is the presence of 2 distinct toxins and variants: stx1 (stx1a, stx1c, and stx1d), and stx2 (stx2a, stx2b, stx2c, stx2d, stx2e, stx2f, and stx2g). The main challenge regarding the study of E. coli is the standardization of a high sensitivity method including all pathotypes, that allows for enrichment of STEC cells and a decrease of background microbiota. The ability of some E. coli cells belonging to other pathogenic groups, such as O104:H4, to acquire genes unique to the STEC group, increases the pathogenic power and the risk of new outbreaks related to these bacteria. In addition, animals with a high concentration of pathogenic E. coli cells present in feces (above 10 4 CFU/g), designated as supershedding animals, may be the primary transmission factor among ruminants. Therefore, the purpose of this review is to address pathogenicity factors and the importance of supershedding animals in the transmission of this pathogen, discussing the main methods currently applied, to focus on the occurrence of STEC in beef.

Salmonella spp is a pathogen responsible for severe foodborne infections, can be introduced into the fish production chain through inadequate handling or hygiene or contact with contaminated water, and is not a biological contaminant originally reported in fish. Fish microbiological safety is a concern for consumers, industries and regulatory agencies worldwide, since fish, an important food category in the international trade and often exported to several countries, can act as a vehicle for Salmonella transmission throughout the production chain. In addition, concerns regarding the misuse of antibiotics in aquaculture are also an issue, as a result of the increased isolation of resistant and multiresistant Salmonella serovars. In this review, we examined aspects associated with the microbiological risks of the presence of Salmonella spp. in fish and their implication in the aquaculture production chain. In addition, incidence and antimicrobial resistance data are presented, as well as strategies for Salmonella prevention and control in fish.

Shiga-toxin producing E. coli (STEC) can cause serious illnesses, including hemorrhagic colitis and hemolytic uremic syndrome. This is the first systematic review of STEC in Brazil, and will report the main serogroups detected in animals, food products and foodborne diseases. Data were obtained from online databases accessed in January 2019. Papers were selected from each database using the Mesh term entries. Although no human disease outbreaks in Brazil related to STEC has been reported, the presence of several serogroups such as O157 and O111 has been verified in animals, food, and humans. Moreover, other serogroups monitored by international federal agencies and involved in outbreak cases worldwide were detected, and other unusual strains were involved in some isolated individual cases of foodborne disease, such as serotype O118:H16 and serogroup O165. The epidemiological data presented herein indicates the presence of several pathogenic serogroups, including O157:H7, O26, O103, and O111, which have been linked to disease outbreaks worldwide. As available data are concentrated in the Sao Paulo state and almost completely lacking in outlying regions, epidemiological monitoring in Brazil for STEC needs to be expanded and food safety standards for this pathogen should be aligned to that of the food safety standards of international bodies.

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Sodium chloride reduction in foods is a significant focus of the dairy industry; however, it can interfere with dairy product quality. Thus, researchers have carried out studies on alternatives to maintain dairy product safety when presenting reduced NaCl content, such as natural antimicrobial addition. Caryocar brasiliense (pequi) is a fruit with high phenolic compound concentrations in the pulp and peel and known antioxidant and antimicrobial properties. This study aimed to define the optimum stage for pequi waste extract addition during cheese manufacturing in order to maintain and prolong the shelf life of reduced-sodium goat Minas Frescal cheese.Four different goat Minas Frescal cheese treatments were carried out: control cheese (without extract; CC), pequi extract addition to milk (CM), pequi extract addition to mass (CS), and cheese immersion in pequi extract (CIE). The treatments were subjected to microbiological (Staphylococcus spp., Escherichia coli, Enterobacteriaceae, coliforms and fecal coliforms, Lactococcus spp., and lactic acid bacteria counts), textural (hardness and consistency), and instrumental color (luminosity, yellow intensity, red intensity, chroma, hue angle, and total color change) analyses. No Enterobacteriaceae, Staphylococcus spp., E. coli, or coliforms and fecal coliforms were detected during storage for any of the assessed samples, including CC. Regarding texture, all samples presented a trend for decreasing rigidity during storage. In addition, lower luminosity values were also observed in cheeses produced with added pequi extract (CM, CS, and CIE) when compared with CC. All cheeses produced with added pequi were stable regarding all evaluated parameters; however, pequi extract addition to milk (CM) was shown to be more efficient, leading to higher textural parameters and better microbiological quality during storage. Thus, the CM treatment is the most recommended for pequi waste extract addition during Minas Frescal cheese manufacture.

Shiga toxin-producing Escherichia coli (STEC) is a group of emerging pathogens that can cause human diseases, including hemolytic uremic syndrome (HUS) and hemorrhagic colitis (HC). Monitoring slaughtering stages and checking contamination points are crucial for the production of safe food. In this context, the aim of this study was to verify contamination by STEC strains, to determine the contamination points and evaluate the resistance profile to 12 antimicrobials used in both veterinary and human medicine. A total of 80 samples were obtained from eight collection points (pen floor, rectum, hide, carcass swabs and esophagus, diaphragm, masseter, and retail beef tissue samples). The isolates were collected by dilution plating on MacConkey agar with sorbitol, cefixime, and tellurite and analyzed by multiplex polymerase chain reaction for virulence genes. Serotyping of non-O157 was performed, and testing for 12 antibiotics by disk diffusion was carried out. A total of 18 STEC strains were isolated, presenting different virulence profiles. Contamination by STEC was observed in the rectum (5/18), carcass surface (5/18), hide (3/18), diaphragm (2/18), retail beef (2/18), and masseter muscle (1/18). Pen floor swabs and esophagus tissues showed no STEC contamination. Moreover, three strains were identified as O26 and three as O113:H21 strains, which have been linked to HUS and HC outbreak cases in Brazil. All STEC isolates were susceptible to all evaluated antimicrobials, except streptomycin. The presence of STEC strains is a direct risk to the consumer, especially when isolated from retail beef, and contamination can occur during different slaughter stages. However, antimicrobial resistance profiles did not identify multidrug-resistant strains, limiting potential antimicrobial resistance transmission to other pathogens.

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