International Risk Assessment Leading to Development of Food Safety Standards

AbstractThe Sanitary and Phytosanitary (SPS) Agreement under the World Trade Organisation (WTO) provides the right to member countries trading in food commodities to take measures to protect plant, animal and human health. However, these measures cannot be arbitrary, but should be based on scientific risk assessments performed according to international standards. The agreement also requires countries to adopt international standards such as those developed by the Codex Alimentarius Commission for food safety and by the World Animal Health Organization (OIE) for animal health. Scientific risk assessments required for development of food safety standards are performed by FAO/WHO. Some examples of food safety standards set by the Codex Alimentarius Commission based on risk assessments are microbiological criteria for Listeria monocytogenes in ready to eat foods and Guidelines for control of pathogenic Vibrio spp in sea foods

Phylogenetic Diversity of Bacterial Community Associated with the Marine Sponge Halichondira nigrocutis Collected off Southwest Indian Coast

This study aimed to evaluate the bacterial communities associated with the marine sponge Halichondria nigrocutis present in Indian waters by both cultivation and cultivation-independent techniques. Results using cultivation method showed that bacteria belonging to Bacillus, Acinetobacter and Vibrio spp. to be the predominant groups. Metagenomic study of sponge-associated bacteria by cultivation independent approach, involving cloning and sequencing of the 16S rDNA gene generated sequences that were subjected to phylogenetic analysis. Results demonstrated the community structure to be represented by the phyla Proteobacteria (alpha-, gamma- and delta-classes), Cyanobacteria, Actinobacteria and Firmicutes, with isolates belonging to alpha-proteobacterial group to be predominating. To our knowledge this study appears to be the first to record cultivable and uncultivable bacterial groups associated with H.nigrocutis from Indian waters

Effect of Ammonia Concentration on the Nitrification Potential of Ammonia Oxidizing Bacterial Isolates from Fish Processing Waste Effluents

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Differential expression of akirin gene in black tiger shrimp Penaeus monodon in response to immunostimulant administration and infections with Vibrio harveyi and white spot syndrome virus

The akirin gene, which is strictly localized in the nucleus, plays a critical role in regulating antimicrobial peptide transcription, and has parallel functions to NF-kappa B signaling pathway in both vertebrates and invertebrates. In shrimp, the akirin gene is expressed as innate immunity in response to microbial infection. In the present study, expression of akirin gene in Penaeus monodon with respect to Vibrio harveyi and white spot syndrome virus (WSSV) infections and immunostimulant (beta-glucan) administration were investigated by quantitative polymerase chain reaction. The gene was expressed in various tissue samples of healthy shrimp. Maximum level of expression was immediately after V. harveyi infection, suggesting that it may be an early response gene. Gene expression was remarkably upregulated in the lymphoid organ, gill, and hepatopancreas, whereas downregulation was observed in hemocytes compared with the control. In the case of WSSV-infected samples, the akirin gene was significantly downregulated in the lymphoid organ but there was no significant difference in expression pattern in hemocytes compared to the control. In gill tissue, maximum expression was observed after 2 hr of infection, the same in hepatopancreas. Experimental challenge of beta-glucan fed shrimp infected with V. harveyi and WSSV resulted in significant upregulation of akirin gene expression in lymphoid and gill tissue

Isolation of Bacterial Pathogens Associated with Commercially Available Spices in Mangaluru City, India

Spices are important sources of natural flavouring, colouring and antimicrobial agents in food and medicine. In India, spices are widely produced, consumed and exported across the world. Like many other agricultural commodities, spices are exposed to a wide range of bacterial contamination during their harvesting, processing and transportation causing foodborne illnesses. Spices in their desiccated form offer an environment conducive to the survival of many pathogenic bacteria which becomes challenging for spice manufacturers to control or mitigate any bacterial contamination. The present study aimed at the isolation, phenotypic and genotypic identification of bacterial pathogens namely Salmonella spp., Bacillus cereus, Staphylococcus aureus and Escherichia coli associated with spices collected in and around Mangaluru, Karnataka. Isolation of bacterial pathogens was performed using a modified standard FDA BAM methodology. A total of 140 spice samples inclusive of pepper, clove, cumin, red chillies, turmeric, coriander, clove and fennel in whole and powdered form were screened for pathogens. No targeted bacterial pathogens were present in the samples collected. It can be inferred that good agricultural, manufacturing and hygienic practices were maintained in the commercial supply of spices. The absence of bacteria could also be attributed to the inherent antimicrobial properties of spices

Microbial community management in aquaculture

Microbial community management in aquaculture creates benefits at the nutritional as well as at health level for cultured species. In addition, in case of biofloc application, it allows to link species at different trophic levels, making bioflocs the potential link in integrated multispecies aquaculture

Bacterial diseases of tilapia, their zoonotic potential and risk of antimicrobial resistance

Tilapia culture is an important source of income and nutrition to many rural families. Since 2000, the production of tilapia increased and reached domestic and global markets. Major farmed species is Nile tilapia (Oreochromis niloticus), in earthen ponds and cage cultures. Intensification contributed to global tilapia disease outbreaks, with bacterial infections causing mortalities and morbidities, threatening sustainable production. At tilapia farms, high nutrient concentrations, water temperature and fish densities enhance bacterial growth including virulent bacterial clones and potential zoonotic bacteria. Global warming favours this. This review respectively provides a comprehensive overview of the most common and emerging bacterial pathogens, diseases, clinical presentations and diagnostics of tilapia, including bacteria and diseases with zoonotic potential. First, common bacterial disease outbreaks, including streptococcosis, motile Aeromonas septicaemia, francisellosis, columnaris disease and vibriosis are described. Then, information on emerging bacterial infections of concern for tilapia, like edwardsiellosis through Edwardsiella ictaluri and E. tarda, as well as Aeromonas schubertii is provided. Reports of infectious bacterial tilapia disease outbreaks from other bacteria, including Lactococcus garvieae, Aerococcus viridans, Pseudomonas spp., Mycobacterium marinum and Chlamydia spp., and others are reviewed. Furthermore, bacteria with zoonotic potential, like Streptococcus agalactiae ST283, S. iniae, Aeromonas sp., E. tarda, Vibrio vulnificus pathovar (pv) piscis and M. marinum are included in the review, to provide the most current overview of the disease risks affecting production and post-harvest stages. Additionally, the status and risks of antimicrobial resistance in bacteria from tilapia and other cultured fish through imprudent use of antibiotics, and its future at a global level are provided

Ecology, Virulence and Detection of Pathogenic and Pandemic Vibrio Parahaemolyticus

Vibrio parahaemolyticus is a gram negative, halophilic bacterium that occurs in the coastal and estuarine environments worldwide and is implicated in several cases of seafood-born gastroenteritis around the globe. However, not all strains of V. parahaemolyticus are pathogenic. Clinical isolates of V. parahaemolyticus most often produce either the thermostable direct haemolysin (TDH) or TDH-related haemolysin (TRH) encoded by tdh and trh genes, respectively. A pandemic clone of O3:K6 which was first detected in Kolkata (India), has been responsible for many outbreaks in Asia and the USA. With the emergence of pandemic clone of V. parahaemolyticus, this organism has assumed significance. Although most of the V. parahaemolyticus outbreaks are invariably related to seafood consumption, pathogenic strains are rarely isolated from seafood. Virulent strains producing TDH or TRH and the pandemic clone, which is responsible for most of the outbreaks (that have occurred after 1996) have been rarely isolated from seafood and other environmental samples. This could be due to the occurrence of pathogenic strains in the estuarine environment at a lower level compared to non-pathogenic strains. Another reason can be that the pathogenic stains are more sensitive to dystropic conditions in the aquatic environment and rapidly become non-culturable. Similarity in growth kinetics between virulent and non-virulent strains also made the isolation of virulent strains from the aquatic environment difficult. Several studies were done to determine the factors responsible for an increased virulence and persistance of pandemic clone. However, none of those studies were conclusive. Several researchers have proposed various genetic markers for specific detection of pandemic clone of V. parahaemolyticus. But many of those genetic markers were found to be unreliable. Recently, seven genomic islands (VPaI-1 to VPaI-7) unique to pandemic clone were identified. This Research Topic is dedicated to improve our current understanding of ecology, pathogenesis and detection of pathogenic and pandemic clone of V. parahaemolyticus, and will also strive to identify areas of future development

Detection of monodon baculovirus and whitespot syndrome virus in apparently healthy Penaeus monodon postJarvae from India by polymerase chain reaction

Abstract The simultaneous presence of monodon baculovirus (MBV) and whitespot syndrome virus (WSSV) in apparently healthy postlarvae of Penaeus monodon from different hatcheries in India was studied by nested polymerase chain reaction (PCR). MBV could be detected in 54% of the samples. However, only 15% of samples were positive by non-nested reaction. WSSV could be detected in 75% of samples, 19% being positive by non-nested reaction. The results show simultaneous presence of WSSV and MBV in many samples at various degrees of infection. Only 14% of the samples analysed were negative for both viruses.