Prevalence and antimicrobial resistance of major foodborne pathogens isolated from pangas and tilapia fish sold in retail markets of Dhaka city, Bangladesh

Fish sold at retail markets are often contaminated with harmful bacterial pathogens, posing significant health risks. Despite the growing aquaculture industry in Bangladesh to meet high demand, little attention has been paid to ensuring the safety of fish. The objective of this study was to evaluate the microbiological quality of tilapia and pangas fish sold in retail markets across Dhaka city, Bangladesh. Specifically, the study aimed to compare the quality of fish from traditional wet markets and modern supermarkets, as well as fish samples collected during morning and evening hours. A total of 500 raw cut-fish samples (250 tilapia and 250 pangas) were collected at the point of sale from 32 wet markets and 25 supermarkets. All samples were tested for Escherichia coli, extended-spectrum β-lactamase-producing E. coli (ESBL-Ec), along with the foodborne pathogens Salmonella, Shigella, Vibrio, and Cryptosporidium spp. Bacterial isolates were characterized using antibiotic susceptibility tests (AST) and the presence of common virulence and antibiotic-resistant genes. Fish samples from retail markets had higher prevalence of tested bacteria including E. coli (92 %), V. cholerae (62 %), ESBL-Ec (48 %), and Salmonella spp. (24 %). There was a significant difference in the prevalence of E. coli (97 % vs. 71 %), ESBL-Ec (58 % vs. 8 %) and Salmonella spp. (28 % vs. 8 %) on the wet market samples compared to supermarket samples (p < 0.005). The mean concentration of E. coli on fish from the wet market was 3.0 ± 0.9 log10 CFU/g, while that from supermarkets was 1.6 ± 0.9 log10 CFU/g. The mean concentration of ESBL-Ec in fish from wet markets and supermarkets were 2.3 ± 0.8 log10 CFU/g and 1.6 ± 0.5 log10 CFU/g, respectively. AST revealed that 46 % of E. coli isolates were multi-drug resistant (MDR), while 4 %, 2 % and 5 % of E. coli, Salmonella spp. and Vibrio spp. isolates, respectively, were resistant to carbapenems. At least 3 % of total E. coli isolates were found to be diarrheagenic, while 40 % of Salmonella isolates harbored pathogenic genes (stn, bcfC, ssaQ, avrA and sodC1), and none of the V. cholerae isolates harbored ctxA and tcpA. Our research shows that raw-cut fish samples from retail markets are contaminated with pathogenic and antibiotic-resistant bacteria, which could be a significant food safety concern. Public health interventions should be implemented to improve food safety and hygiene practices in the retail fish markets.

Using fresh vegetable waste from Chinese traditional wet markets as animal feed: Material feasibility and utilization potential

To develop new animal feed sources and establish a sustainable food upcycling system, the material feasibility and feeding potential of fresh vegetable waste (FVW) were clarified in this study. First, the FVW output of wet markets in Hangzhou, China was tracked and predicted. The results showed that the retail waste ratio of FVW in wet markets reached 9.3 %, predicting that China's FVW will reach 9034 kt in 2030. Second, the study revealed that the nutritive value of FVW was comparable to that of traditional alfalfa feed, suitable for use as animal feed. However, we found a high probability of microbial contamination. Therefore, FVW should have stricter classification and collection methods. Under this premise, the feeding utilization potential of FVW in wet markets is large. In 2030, the crude protein content may replace 2737 kt of alfalfa, saving 7.7 E + 08 m3 of water and 75,018 ha of land.

Live poultry markets beyond health risks: Understanding consumer preferences for live poultry in South China

Live poultry markets (LPMs) are veterinary and public health risks because of potential for zoonotic spillover of pathogens from diseased animals to humans. To control these health risks, veterinary and public health authorities in Asia, including China, have closed or restricted LPMs. In south China, however, LPM closure has been opposed or rendered infeasible by consumers who prefer to purchase live poultry. Previous scholarship has suggested this preference is due to cultural values of freshness. In this study, we present results from detailed interviews with shoppers in south China, including those who prefer live poultry and those who prefer pre-slaughtered poultry. We argue that broader concerns about food safety and quality, rather than freshness alone, drive the demand for LPMs. Live poultry provide sensory information that enable shoppers to evaluate safety and quality in ways that are not possible with pre-slaughtered, refrigerated meat. Based on these findings, we suggest that hygienic interventions into LPMs should recognize that not only freshness, but also trust, must be constructed and maintained in any intervention.

Wildlife Consumption, Health, and Zoonotic Disease in China After the Emergence of COVID-19

There has been much discussion in the conservation and policy realms of COVID-19 as a zoonotic disease, or a disease transmitted from wildlife to humans. However, wildlife consumption in China is not only a potential source of disease but also a practice embedded in complex beliefs about health. This paper used survey data (N = 974) collected in China in June 2021 to examine attitudes and behaviors related to (a) wildlife consumption, (b) Traditional Chinese Medicine (TCM) and (c) zoonotic risk after the emergence of the COVID-19 pandemic. 40.1% of respondents self-reported that they are less likely to consume wild animals since the outbreak of COVID-19. Respondents who used wildlife supplements for TCM, who believed in the benefits of wild animal consumption and fresh slaughter of wildlife, and who had higher levels of agreement with the zoonotic origin of COVID-19 were more likely to report that they had decreased their wildlife consumption after the outbreak of COVID-19. Use of wildlife in TCM significantly increased the odds that a respondent believed that COVID-19 was very likely zoonotic. We discuss how situating wildlife consumption within complex beliefs about health and disease can assist with protecting wildlife and public health in the wake of COVID-19.

A Multi-landscape Assessment of Leptospira Prevalence on a Diversity of Small Mammals

Leptospirosis is a major zoonotic disease, especially in the tropics, and rodents were known to be carriers of this bacterium. There was established information on Leptospira prevalence among animal reservoirs in human-dominated landscapes from previous literature. However, there was very little focus given comparing the prevalence of Leptospira in a wide range of habitats. An extensive sampling of small mammals from various landscapes was carried out, covering oil palm plantations, paddy fields, recreational forests, semi-urbans, and wet markets in Peninsular Malaysia. This study aims to determine the prevalence of pathogenic Leptospira in a diversity of small mammals across different landscapes. Cage-trapping was deployed for small mammals' trappings, and the kidneys of captured individuals were extracted, for screening of pathogenic Leptospira by polymerase chain reaction (PCR) using LipL32 primer. Eight microhabitat parameters were measured at each study site. Out of 357 individuals captured, 21 (5.9%) were positive for pathogenic Leptospira of which recreational forest had the highest prevalence (8.8%) for landscape types, whereas Sundamys muelleri shows the highest prevalence (50%) among small mammals' species. Microhabitat analysis reveals that rubbish quantity (p < 0.05) significantly influenced the Leptospira prevalence among small mammals. Furthermore, nMDS analysis indicates that the presence of faeces, food waste, and exposure to humans in each landscape type also were linked with high prevalence of pathogenic Leptospira among the small mammals. This study supplements previous studies on pathogenic Leptospira prevalence across different landscape types, and the major microhabitat factors associated with Leptospira prevalence. This information is crucial for epidemiological surveillance and habitat management to curb the possibility of the disease outbreaks.

Exploring customers' perceptions of food adulteration at bazaars and supermarkets in Dhaka, Bangladesh; a qualitative exploration

BACKGROUND

Food adulteration is an increasingly recognized global public health problem. In low- and middle-income countries like Bangladesh, adulteration is difficult to detect and respond to. We explored customers' perceptions on food adulteration, perception of risk and connections between information, participant characteristics and patterns of adulterated food concerns that impact risk perception in urban Bangladesh.

METHODS

A formative study was conducted in Dhaka, between June and August 2015 at a supermarket and a wet market. We explored community awareness and response to chemical contaminants (adulterants) among participants from a range of socio-economic backgrounds. The team conducted 38 in-depth interviews with 12 customers and 4 staff from a supermarket, and 12 customers and 10 vendors from a wet market. Participants were selected purposively. Audio recorded data were coded based on thematic content and analyzed manually.

RESULTS

We asked participants how common foods were likely adulterated, and most gave figures of 70% or more. They reported that foods were adulterated with chemicals or artificial colors, especially fish, milk, and vegetables. The supermarket more commonly sold packaged foods with nutritional and expiry information on the label; and offered convenience in terms of building size, layout, and cleanliness. All customers from the wet market thought that foods were cheaper and fresher than from supermarkets. Supermarket customers expressed greater concern about adulterated foods than wet market customers. Most participants from both markets reported that food adulteration is invisible, adulterated foods cannot be avoided, and have long-term negative health impacts including cancer, diabetes, paralysis, heart attack, and others. Nearly half of customers from both markets were concerned about the poor nutritional value of adulterated food. Participants from both settings expressed the need for access to credible information about adulteration to help choose safe foods. The majority expressed the need for government action against those who are responsible for adulteration.

CONCLUSIONS

Food adulteration was considered a major health threat. The government could act on food adulteration prevention if provided credible population-based data on disease burden, a model food sampling and testing protocol, a model for inspections, organizational strengthening and training, example social and behavioral change communications with estimated costs.

Early impact of COVID-19 pandemic on the molluscan shellfish supply chain in China

A farm-level survey and a market survey were conducted in China to study the impact of the COVID-19 on the shellfish supply chain in the early stage of the pandemic in 2020. 114 farms of 36 cites participated in an online survey from mid-July to late August, and 23 markets in five cities were investigated from June to November. The series results are expected to provide an insight for the fisheries and aquaculture sector to mitigate the impact of the pandemic on participants in the shellfish supply chain and to improve of the ability of the government to respond to such events in the future. Shellfish farmers and sellers have experienced a sharp drop in profits, largely due to shrinking demand. Relying on local employees and suppliers, shellfish farming activities have rapidly resumed since the gradual reopening from February. Nevertheless, demand has been slow to recover due to public concern about contamination of seafood with the virus. Additionally, we analyzed the ability and attitude of farms of different size to cope with the pandemic and the plight of shellfish sellers, and discussed government supports for different size farms and improvements in seafood distribution channels.

Beta-agonist residues in cattle, chicken and swine livers at the wet market and the environmental impacts of wastewater from livestock farms in Selangor State, Malaysia

Fourteen beta-agonists were quantitatively analyzed in cattle, chicken and swine liver specimens purchased at 14 wet markets in Selangor State, Malaysia, by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The health risks of ractopamine and clenbuterol residues in the Malaysian population were assessed based on quantitative data and meat consumption statistics in Malaysia. Wastewater samples collected at swine farms (n = 2) and cattle/cow farms (n = 2) in the Kuala Langat district were analyzed for the presence for the 14 compounds. Wastewater in chicken farms was not collected because there was negligible discharge during the breeding period. The environmental impacts caused by beta-agonists discharged from livestock farms were spatially assessed in the Langat River basin using a geographic information system (GIS). As a result, 10 compounds were detected in the liver specimens. Ractopamine, which is a permitted compound for swine in Malaysia, was frequently detected in swine livers; also, 9 other compounds that are prohibited compounds could be illegally abused among livestock farms. The health risks of ractopamine and clenbuterol were assessed to be minimal as their hazard quotients were no more than 7.82 × 10^-4 and 2.71 × 10^-3, respectively. Five beta-agonists were detected in the wastewater samples, and ractopamine in the swine farm resulted in the highest contamination (30.1 μg/L). The environmental impacts of the beta-agonists in the Langat River basin were generally concluded to be minimal, but the ractopamine contamination released from swine farms was localized in coastal areas near the estuary of the Langat River basin because most swine farms were located in that region.

Airborne bacterial contaminations in typical Chinese wet market with live poultry trade

Chinese wet markets with live poultry trade have been considered as major sources of pathogen dissemination, and sites for horizontal transfer of bacterial and viral pathogens. In this study, the pathogenic bacteria and antibiotic resistant genes (ARGs) in air samples collected at a typical Chinese wet market had been analysis and quantified. Corynebacterium minutissimum and other pathogenic bacteria accounted for 0.81-8.02% of the whole microbial community in different air samples. The four ARGs quantified in this study showed a comparable relative concentration (copies/ng_DNA) with municipal wastewater. Poultry manures were demonstrated to be important microbial contamination source in wet market, which was supported by both microbial composition based source tracking and the quantification of airborne microbial density. A series of Firmicutes and Bacteroidetes indicators of poultry area contamination were successfully screened, which will be useful for the more convenient monitoring of airborne poultry area contamination. Our results indicate bioaerosols acted as important route for the transmissions of pathogens and ARGs. Continued surveillance of airborne microbial contamination is required in poultry trade wet market.

PRACTICAL IMPLICATIONS

Urban live poultry markets are important sources of pathogen dissemination, and sites for horizontal transfer of viral and bacterial pathogens. In the present field-study, pathogenic bacteria and antibiotic resistance genes were focused to provide quantitative information on the levels of microbial contaminations at the indoor air of wet markets. Results demonstrated that poultry manures were important microbial contamination source in wet market, and in the meanwhile bioaerosols were identified as important route for the transmissions of microbial contaminants. A series of Firmicutes and Bacteroidetes indicators of poultry area contamination were successfully screened, which will be useful for the more convenient monitoring of airborne poultry area contamination.

Rodents as a Source of Salmonella Contamination in Wet Markets in Thailand

BACKGROUND

Few studies have been conducted on the presence of Salmonella in the rodents that inhabit the wet markets that play an important role in daily life in Southeast Asia. The results of studies of rodents as carriers of Salmonella vary greatly, ranging from an absence of Salmonella to high prevalences. Previous studies investigated habitats such as farms and urban and wild areas where there is less rodent-human interaction than in wet markets. Consequently, the potential role of rodents as reservoirs and transmitters of Salmonella in wet markets is of great interest.

METHODS

Rodents were trapped in eight traditional wet markets in Thailand and identified to species level. Subsequently, they were screened for Salmonella and isolates were serotyped.

RESULTS

A total of 110 rats (Rattus norvegicus and Rattus exulans) were examined. Overall, the prevalence of Salmonella in rats was 49.10%, but varied between 0% and 73.3% among markets. Three serovars were identified: Salmonella Typhimurium (30%), S. Weltevreden (12.7%), and S. 4,[5],12:i:- (6.4%).

CONCLUSIONS

Our results show that rodents in wet markets are a potential reservoir of Salmonella due to the close contact they have with humans and food. The three isolated serovars, of which serovar S. 4,[5],12:i:- is reported for the first time in rodents, are among the 10 commonest serovars isolated from humans in Thailand. Thus, more attention should be paid to rodents as potential reservoirs of Salmonella.

Site verification and modeling of desiccant-based system as an alternative to conventional air-conditioning systems for wet markets

Desiccant cooling system for active humidity control and to conserve energy has been in commercial applications for over two decades. However, its use in humid wet markets has never been examined. A gas-fired desiccant cooling system has been installed in a wet market in Hong Kong. In this study, the annual energy saving in conjunction with the use of desiccant cooling system was investigated by in-situ measurements, site surveys and simulations. The verified computer model was used for further simulations. It was found that for the use of a minimum ventilation rate of 10.3 L/s/person, the use of desiccant cooling system as compared to conventional system saved 4% of the energy and could achieve the desired space conditions. A parametric study under various ventilation rates indicated that use of desiccant cooling system in wet markets in hot and humid Hong Kong would lead to energy and energy cost savings, as well as CO₂ emission reduction amounting from 1% to 13%. The savings were more evident when wet markets were designed for a ventilation rate of 20 L/s/person. Furthermore, the actual occupancy profile, and lighting and small power densities determined in this study would be useful for future studies on wet market.