Understanding the management practices of animal manure and associated risks of transference of bacterial pathogens to crop vegetables

Manure is commonly used in agricultural production in Mauritius, but little is documented on the local management practices. Animal manure, in particular, is a livestock waste that harbors enteric microorganisms which are potentially pathogenic to humans. The objectives of the study were therefore (i) to shed light on the management practices of manure among cattle and poultry farmers  (manure producers) and carrot and lettuce growers (manure end-users) and any associated health risks and (ii) to determine the prevalence of human pathogens (diarrheagenic Escherichia coli, Salmonella, Listeria monocytogenes and Clostridium perfringens) in manure collected from farmers, vegetable crops fertilized with manure as well as manure-amended soil (MAS) used in crop cultivation. A survey was conducted through in-depth interviews with 16 producers and 36 end-users to gather data on their MMP and their  perception of the health risks associated with manure handling. Samples of manure, MAS and vegetables were also microbiologically analyzed to enumerate and/or detect pathogens. Findings revealed that cattle and poultry manure was an important resource for many small-holder vegetable farmers in Mauritius. The manure distributors or end users had no negative perception of the use of untreated manure for vegetable cultivation and were generally unaware of any biosecurity risks arising from the improper handling or subsequent use of untreated manure. Microbiological analyses however showed that 100% of manure samples collected from cattle farms and 58% of the poultry litter samples tested positive for pathogenic E. coli with population ranging from 3.3 to 6.5 Log CFU/g. Manure-borne pathogens were generally undetectable in the analyzed vegetables hence indicating a low risk of foodborne infections. However, the systematic presence of pathogenic E. coli in cattle manure and frequent occurrence in poultry litter clearly point to a need for creating greater awareness amongst farmers on the occupational health risks associated with handling of raw or inadequately decomposed manure. This study therefore points to the health risks associated with enteric pathogens present in raw or untreated raw manure in Mauritius. Key words: Manure Management, Pathogens, E. coli, Salmonella, Cattle, Poultry, Carrot, Lettuce, Mauritiu

A study on the potential of ants to act as vectors of foodborne pathogens

Ants (Technomyrmex difficilis and Solenopsis geminata) are insects often found in domestic kitchens of Mauritius. Unfortunately, they harbour disease-causing organisms and can potentially transfer these pathogens to food. This study was carried out to (i) investigate the knowledge, perception and behaviors of consumers in relation to the problem of ant infestation of domestic kitchens; (ii) identify the pathogenic microorganisms carried by ants; and (iii) determine the potential for ants to transfer these pathogenic microorganisms to food. A survey based on a stratified sampling design was carried out with 100 consumers using a questionnaire. To identify the pathogenic microorganism(s) harbored by ants, bait traps were set up using sterile sugar as a non-toxic attractant. Captured ants were then subjected to microbiological analyses. Most respondents (72%) agreed that ants constitute a hygienic issue but they did not perceive ants as a serious threat to human health. However microbiological analyses of ants (n = 50) confirmed the presence of various pathogenic microorganisms as well as fecal contaminants. Ants were found to harbor yeasts and molds systematically (100%), coliforms frequently (52%), Bacillus spp. and Escherichia coli occasionally (26% and 18% respectively) and Salmonella and Listeria monocytogenes sporadically (8 and 6 % respectively). Ants were also found to transfer E. coli to food surfaces at a moderately high frequency of 70%. This study demonstrated that the majority of consumers acknowledged the problem of ant infestation as a sanitation-related problem rather than a food safety issue. Since ants have the ability to harbor and subsequently transfer pathogenic or toxigenic microorganisms, ants may act as disease vectors and contaminate food, water and food-contact surfaces of kitchens resulting in foodborne illnesses

Assessment of the microbiological quality of popular food items on sale in secondary school canteens of Mauritius

This study was carried out to assess the microbiological status of three hot meals served in eight selected school canteens of Mauritius, with two schools randomly selected from each of the four school zones of the island. Three individual samples of farata, panini, or fried noodles were collected at each school during two independent visits. The three individual samples of each food type collected during each visit were then pooled before being subjected to microbiological analyses. A total of 48 composite samples were analyzed. The parameters tested were Total Viable Count (TVC), Escherichia coli, Salmonella spp., Clostridium perfringens, Staphylococcus aureus, and Listeria spp. The microbiological analyses revealed that paninis were deemed as generally acceptable with TVC falling in the range of 3.0-5.7 Log CFU/g and undetectable levels of S. aureus and E. coli. In contrast, fried noodles and faratas harboured a moderately high level of TVC (4.4-6.7 Log CFU/g) and objectionably high levels S. aureus (3.1 to 5.0 Log CFU/g) and E. coli (3.1-5.1 Log CFU/g) for seven out of the eight schools

The emerging pharmacology and function of GPR35 in the nervous system

G protein-coupled receptor 35 (GPR35) is an orphan G protein-coupled receptor (GPCR) that can be activated by kynurenic acid at high micromolar concentrations. A previously unappreciated mechanism of action of GPR35 has emerged as a Gαi/o-coupled inhibitor of synaptic transmission, a finding that has significant implications for the accepted role of kynurenic acid as a broad-spectrum antagonist of the NMDA, AMPA/kainite and α7 nicotinic receptors. In conjunction with previous findings that link agonism of GPR35 with significant reduction in nociceptive pain, GPR35 has emerged as a potential effector of regulation of mechanical sensitivity and analgesia of the Ret tyrosine kinase, and as a receptor involved in the transmission of anti-inflammatory effects of aspirin- potentially through affecting leucocyte rolling, adhesion and extravasation. Single nucleotide polymorphisms of GPR35 have linked this receptor to coronary artery calcification, inflammatory bowel disease and primary sclerosing cholangitis, while chromosomal aberrations of the 2q37.3 locus and altered copy number of GPR35 have been linked with autism, Albight's hereditary osteodystrophy-like syndrome, and congenital malformations, respectively. Herein, we present an update on both the pharmacology and potential function of GPR35, particularly pertaining to the nervous system. This review forms part of a special edition focussing on the role of lipid-sensing GPCRs in the nervous system

Use of Antimicrobial Films and Edible Coatings Incorporating Chemical and Biological Preservatives to Control Growth of Listeria monocytogenes on Cold Smoked Salmon

The relatively high incidence of Listeria monocytogenes in cold smoked salmon (CSS) is of concern as it is a refrigerated processed food of extended durability (REPFED). The objectives of this study were to compare and optimize the antimicrobial effectiveness of films and coatings incorporating nisin (Nis) and sodium lactate (SL), sodium diacetate (SD), potassium sorbate (PS), and/or sodium benzoate (SB) in binary or ternary combinations on CSS. Surface treatments incorporating Nis (25000 IU/mL) in combination with PS (0.3%) and SB (0.1%) had the highest inhibitory activity, reducing the population of L. monocytogenes by a maximum of 3.3 log CFU/cm2 (films) and 2.9 log CFU/cm2 (coatings) relative to control samples after 10 days of storage at 21°C. During refrigerated storage, coatings were more effective in inhibiting growth of L. monocytogenes than their film counterparts. Cellulose-based coatings incorporating Nis, PS, and SB reduced the population of L. monocytogenes, and anaerobic and aerobic spoilage flora by a maximum of 4.2, 4.8, and 4.9 log CFU/cm2, respectively, after 4 weeks of refrigerated storage. This study highlights the effectiveness of cellulose-based edible coatings incorporating generally regarded as safe (GRAS) natural and chemical antimicrobials to inhibit the development of L. monocytogenes and spoilage microflora thus enhancing the safety and quality of CSS

Antilisterial activity of <em>Cymbopogon citratus</em> on crabsticks

Listeria monocytogenes is a gram positive, psychrotrophic, facultative anaerobic bacterium and it is the etiological agent of listeriosis, a severe foodborne disease of major public health concern. There is a rising concern about the cross-contamination of surimi-based products with L. monocytogenes during handling and storage. Lemon grass (Cymbopogon citratus) is known to exhibit strong antimicrobial activity against bacteria due to the presence of citral. The objectives of this research were: (i) to develop a water-based extraction procedure for the antimicrobial component(s) in lemon grass and (ii) to evaluate the antimicrobial effect of a concentrated water-based extract and commercial essential oil (EO) of lemon grass against L. innocua (ATCC 33090), a surrogate strain of L. monocytogenes, in vitro and on crabsticks. Briefly, antilisterial activity of concentrated extract and commercial EO of lemon grass was tested using the agar well diffusion technique. Crabsticks were subsequently inoculated with L. innocua to a final density of ca. 4 log cfu/g and then coated with 500 ml of either concentrated extract or 0.5% commercial EO and stored at 4 °C for up to 15 days. Samples were then subjected to microbiological analysis every 5 days to enumerate counts of Listeria. Following the agar well diffusion assay, inhibition zones with mean diameters of 18.3 and 21.0 mm were obtained with the concentrated extract and commercial EO respectively. The population of L. innocua in WBE-coated (4.2 log cfu/g) and 0.5% EO-coated (2.7 log cfu/g) samples were significantly lower (P &lt; 0.05) after 15 days than their untreated control counterpart (5.2 log cfu/g). Lemon grass extract and essential oil have the potential to control growth of L. monocytogenes in seafood surimi products with minimal adverse effect on the organoleptic characteristics of the product and thus can possibly be used as a natural food preservative

Use of Antimicrobial Films and Edible Coatings Incorporating Chemical and Biological Preservatives to Control Growth of Listeria monocytogenes on Cold Smoked Salmon

The relatively high incidence of Listeria monocytogenes in cold smoked salmon (CSS) is of concern as it is a refrigerated processed food of extended durability (REPFED). The objectives of this study were to compare and optimize the antimicrobial effectiveness of films and coatings incorporating nisin (Nis) and sodium lactate (SL), sodium diacetate (SD), potassium sorbate (PS), and/or sodium benzoate (SB) in binary or ternary combinations on CSS. Surface treatments incorporating Nis (25000 IU/mL) in combination with PS (0.3%) and SB (0.1%) had the highest inhibitory activity, reducing the population of L. monocytogenes by a maximum of 3.3 log CFU/cm 2 (films) and 2.9 log CFU/cm 2 (coatings) relative to control samples after 10 days of storage at 21 ∘ C. During refrigerated storage, coatings were more effective in inhibiting growth of L. monocytogenes than their film counterparts. Cellulosebased coatings incorporating Nis, PS, and SB reduced the population of L. monocytogenes, and anaerobic and aerobic spoilage flora by a maximum of 4.2, 4.8, and 4.9 log CFU/cm 2 , respectively, after 4 weeks of refrigerated storage. This study highlights the effectiveness of cellulose-based edible coatings incorporating generally regarded as safe (GRAS) natural and chemical antimicrobials to inhibit the development of L. monocytogenes and spoilage microflora thus enhancing the safety and quality of CSS