Investigating the Effect of Probiotics as Natural Preservatives on the Microbial and Physicochemical Properties of Yogurt-Marinated Chicken Fillets

Microbial flora of probiotic yogurt can have nutraceutical properties and improve beneficial health effects of food products. In this study, microbial and physicochemical properties of raw chicken fillets dipped in regular yogurt and probiotic yogurt containing Lactobacillus casei, preserved at 4°C for 9 days, were studied. In this regard, microbial analysis (Staphylococcus aureus, fecal coliform, yeasts, and molds) and physicochemical analysis (pH, water holding capacity, cooking loss percentage, Thiobarbituric acid reactive substances, and texture profile analysis) were performed during the storage time. In comparison with control samples, the amount of Staphylococcus aureus, fecal coliforms, yeast and mold counts, pH index, malondialdehyde value, and cooking loss percentage reduced significantly ( P < 0.05 ) in the chicken fillets treated with regular and probiotic yogurt, while the water holding capacity increased in six days. It was concluded that probiotic and regular yogurts reduced microbial growth and improved the physicochemical quality of chicken fillets during storage and cooking time.

Detection of fecal coliforms and SARS-CoV-2 RNA in sewage and recreational waters in the Ecuadorian Coast: a call for improving water quality regulation

Wastewater surveillance represents an alternative approach for the diagnosis and early detection of infectious agents of public health importance. This study aimed to evaluate SARS-CoV-2 and other quality markers in oxidation lagoons, estuarine areas and seawater at Guayas and Santa Elena in Ecuador. Sample collections were conducted twice at 42 coastal sites and 2 oxidation lagoons during dry and rainy seasons (2020-2021). Physico-chemical and microbiological parameters were evaluated to determine organic pollution. Quantitative reverse transcription PCR was conducted to detect SARS-CoV-2. Results showed high levels of Escherichia coli and low dissolved oxygen concentrations. SARS-CoV-2 was detected in sea-waters and estuaries with salinity levels between 34.2-36.4 PSU and 28.8 degrees celsius -31.3 degrees celsius. High amounts of fecal coliforms were detected and correlated with the SARS-CoV-2 shedding. We recommend to decentralized autonomous governments in developing countries such as Ecuador to implement corrective actions and establish medium-term mechanisms to minimize a potential contamination route.

Microbiological Quality of Egusi Pudding, A Traditional Cake of Cucurbitaceae Sold in the City of Yaoundé, Cameroon

Egusi pudding is one of the most popular traditional dishes of the Cameroonian population. Besides its nutritional values, it is also endowed with a sociocultural character. Nowadays, consumer demand for Egusi pudding has increased and the dish is sold as street food in several cities of Cameroon and mostly under uncontrolled hygienic conditions. The objective of this study was to assess the microbiological quality of Egusi pudding sold in the city of Yaoundé taking into consideration the protein sources and the sampling sites. Five types of Egusi pudding samples based on protein sources were randomly collected from 25 sellers distributed in 7 districts in the city of Yaoundé and their microbiological quality were assessed. The results showed that the total aerobic count of the different samples (2.97 ± 0.03 to 4.43 ± 0.05 Log CFU/g) was under the threshold value (5.47 Log CFU/g) recommended for food intended for human consumption. Loads of fecal coliforms (1.47 ± 0.00 to 5.47 ± 0.00 Log CFU/g) in 40% of samples, Escherichia coli (2.39 ± 0.12 to 5.43 ± 0.05 Log CFU/g) in 60% of samples, fecal streptococci (2.90 ± 0.15 to 4.74 ± 0.05 Log CFU/g) in 88% of samples, Pseudomonas spp. (3.39 ± 0.15 to 5.43 ± 0.06 Log CFU/g) in 100% of samples, and the presence of Salmonella spp. in 56% of samples revealed a poor level of hygiene of the vendors. Pathogens associated with unsafe food handling such as Staphylococcus spp. were found in 100% of samples at loads (3.84 ± 0.18 to 5.43 ± 0.05 Log cfu/g) higher than the norms of the European Commission. Potential toxigenic pathogens such as Clostridium perfringens, Yersinia enterocolitica, Bacillus cereus, and moulds were also found, respectively, in 100, 96, 96, and 100% of samples. Overall, the most contaminated samples were those made with sardine as protein source, 92.85% (n = 23/25), followed with beef (88.57%), mackerel (84.28%), cod (82.85%), and control (77.1%). The results of this study suggest that important measures should be taken by the Public Health Service in order to sensitize the producers and vendors of Egusi pudding on the respect of good hygiene, manufacturing practices, and the continuous monitor of the quality of traditional products sold in markets.

Physico-chemical and microbiological characteristics of water for domestic use in Cotonou in the republic of Benin

Water is the source of life. It is essential for the survival of all living things. However, its alteration becomes harmful to humans. In Cotonou, the main city of Benin, the quality of drinking water is worrying because of many factors such as environmental pollution and poor hygiene around water sources. In fact, poorly ecological management methods of household waste pose risks of contamination of soil and water resources. This study aims to assess the quality of domestic water for households in the city of Cotonou. The methodology adopted is summed up in a physico-chemical and microbiological analysis of thirty water samples taken from households in the 13 districts of the city of Cotonou. The results obtained at the physicochemical level show that, apart from the waters of SONEB at the source, whose turbidity (5.6 NTU) complies with the standard which is 5 NTU, that of other sources is much greater than Standard. This indicates the presence of suspended solids in the water that may harbor microorganisms harmful to humans. With regard to microbiological quality, all the water sampled at household level contains E.Coli, the number of which is much higher than the Benin standard which sets at 0/1 ml of water. In addition, the water sampled from the wells contains high numbers of fecal coliforms. As for SONEB water, the presence of coliforms was determined but with lower numbers than well water (50 / ml at household level and 2 / ml at source level.

Bacterial diversity and potential risk factors associated with Salmonella contamination of seafood products sold in retail markets in Bangkok, Thailand

Consumption of contaminated food causes 600 million cases, including 420,000 of fatal infections every year. Estimated cost from food-borne illnesses is USD 110 billion per year, which is an economic burden to low- and middle-income countries. Thailand is a leading producer and consumer of seafood, but little is known about bacterial contamination in seafood. In particular, public health agencies need to know the relationship between Salmonella contamination in seafood and risk factors, as assessed with readily available culture-dependent and bacterial phenotyping methods. To address this, levels of indicator bacteria, Salmonella and Vibrio in various seafood products were determined to identify risk factors associated with Salmonella contamination. A total of 335 samples were collected from October 2018 to July 2019 at seafood markets throughout Bangkok, Thailand; overall sample composition was Pacific white shrimp (n = 85), oysters (n = 82), blood cockles (n = 84), and Asian seabass (n = 84). Prevalence was 100% for fecal coliforms and 85% for E. coli. In contrast, prevalence was 59% for V. parahaemolyticus, 49% for V. cholerae, 19% for V. alginolyticus, 18% for V. vulnificus, and 36% for Salmonella. Highest concentrations of fecal coliforms and E. coli were in oysters. Highest concentrations of Salmonella with Matopeni (31%) being the predominant serotype were in shrimp. Salmonella contamination was significantly associated with type of seafood, sampling location, retail conditions, and the presence of E. coli, V. alginolyticus and V. vulnificus. A cutoff value for E. coli concentration of 1.3 × 104 MPN/g predicted contamination of Salmonella, with a sensitivity of 84% and specificity of 61%. Displaying seafood products on ice, presence of E. coli and Vibrio, and seafood derived from Eastern Thailand were associated with an increased risk of Salmonella contamination.

Environmental and Fecal Indicator Organisms on Fruit Contact Surfaces and Fruit from Blueberry Mechanical Harvesters

Although previous studies have examined microbial loads on food contact surfaces in blueberry packing plants, there is currently no information regarding microbial risks associated with mechanical berry harvesters used in commercial blueberry production. In this study, we surveyed up to nine fruit contact surfaces on seven mechanical harvesters in each of 2015 and 2016 in the field. These surfaces included the shaking rods at the front of the harvester, the sidewalls of the harvesting tunnel behind the shaking mechanism, the catcher plates collecting the detached berries, horizontal and vertical fruit conveyor belts, and berry lugs collecting the fruit at the back of the harvester. Swab samples were collected from each surface three times a day (morning, noon, and evening) and assessed for environmental and fecal indicator organisms including total aerobes, total yeasts and molds, coliforms and fecal coliforms, and enterococci. At the same time points, fruit samples were assessed for microbial loads before the fruit entered each harvester and after they exited the harvester. Results showed statistically significant differences in microbial loads among harvester surfaces, whereas the effect of sampling time was generally not significant. High levels of total aerobes and total yeasts and molds were recorded, especially on horizontal surfaces and/or those located at the bottom of the harvester such as the lower sidewall, the catcher plates, and the horizontal conveyor belt. These surfaces therefore should be targeted by cleaning and sanitization practices. There was also statistical evidence that passage through the harvester may increase the levels of the environmental microorganisms on fruit in the field. In contrast, fecal indicator organisms such as fecal coliforms and enterococci were detected only sporadically and at very low densities on harvester surfaces and blueberry fruit, and there was no evidence that passage through the harvester increased their levels on the fruit. Berry lugs consistently harbored microbial loads, and given their movement back and forth between the field and the packing plant, deserve particular attention with regard to cleaning, sanitization, and storage protocols.

Predictive modeling to determine oxygen and ozone doses applicable to in situ remediation of polluted water bodies

This work shows the results for the first time of calibrating and validating a mathematical model, capable of predicting the amounts of O3 and O2 necessary to reduce pollution levels in a lake based on the Chemical Oxygen Demand (COD), Biochemical Oxygen Demand (BOD5), Total nitrogen (TN), Total phosphorus (TP) and Fecal coliforms (FC) concentrations. The model was designed to treat a natural or artificial lake as though it were an aerated lagoon operating as an idealized Continuous flow complete-mix reactor. The O3 yield constant for eliminating the non-biodegradable fraction of COD and for deactivating fecal coliforms were laboratory derived and calibrated with field values. Based on the field parameters, the model accurately predicted a reduction in BOD5, COD, TN, TP and FC of 53 %, 51 %, 39 %, 42 % and 98 %, respectively. The model proved to be effective in predicting O2 and O3 demand and time of recovery of a polluted water body.

Multiple Indicators of Wastewater Contamination to Shellfish Farms Near a Tidal River

Wastewater contamination threatens the shellfish aquaculture industry by posing risks to public health. Multiple indicators of wastewater contamination, including fecal coliforms (fc), male-specific coliphage (MSC), dissolved nutrients, stable isotope ratios, and artificial sweeteners were analyzed to determine possible sources of wastewater to local shellfish farms. Samples were collected at a wastewater treatment plant outfall (WTPO), nonpoint residential, and agricultural areas of a tidal river, and tidal creek inflows adjacent to farms. To capture seasonal variation, we sampled under warm and cold, and wet and dry conditions. Fc ranged < 5–5250 CFU 100 mL−1, NH4+ concentrations ranged up to 9.58 μM, and δ15N ranged 1.4–7.8‰ across all sites and time periods. Fc and NH4+ were higher, and δ15N was lower in the cold wet period and near residential and agricultural areas. Acesulfame and sucralose concentrations ranged 0.004–0.05 μg L−1 and up to > 0.8 μg L−1, respectively, and did not correlate with other indicators but tended to be higher in residential areas and at the WTPO, supporting their value in differentiating human sewage from other sources. Shoreline disturbance during septic system upgrades may have inadvertently contributed bacterial indicators to shellfish farms. Overall, indicator source dominance depended on environmental conditions, with WTPO and residential sources conveying human-specific indicators to farms year-round, while agricultural and industrial sites contributed additional fc during cold wet periods. The use of multiple indicators will aid managers to detect and define wastewater sources, identify targets for monitoring or remediation, and manage shellfish areas in estuaries with a mosaic of land-derived wastewater sources.