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

Greenhouse-grown tomatoes : microbial diseases and their control methods : a review

The cultivation of tomatoes in greenhouse structures is becoming increasingly common as a crop production system. However, the environmental conditions inside a greenhouse favour the development of microbial diseases. These diseases have an adverse effect on the tomato yield and can lead to serious economic losses. This review will give an insight into the major diseases affecting greenhouse-grown tomatoes, the respective causal agents and recommended control strategies. Some of the major diseases are of a bacterial, fungal, viral or nematode origin and include bacterial spot and speck, bacterial canker, early blight, gray mold, leaf mold, powdery mildew, tomato mosaic virus, tomato big bug and root knot. For each disease, the symptoms and risk factors responsible for disease development are described. In addition, the different structural designs and set-ups of tomato greenhouses are covered along with their advantages and limitations, especially any adverse effects on yield and susceptibility to disease. Although conventional control measures are discussed, greater emphasis is laid on the use of alternative biocontrol measures that include Effective Microorganisms, natural antimicrobials and nanobiopesticides. Moreover, information gathered in this review is based on a combination of available literature and expert guidance. This compilation is hoped to be instructive for tomato growers opting for greenhouse farming and assist them in the application of timely and more effective control measures.https://esciencepress.net/journals/phytopathhj2024Forestry and Agricultural Biotechnology Institute (FABI)SDG-02:Zero Hunge

Listeria monocytogenes at the food–human interface : a review of risk factors influencing transmission and consumer exposure in Africa

DATA AVAILABILITY STATEMENT: Data sharing not applicable - no new data generated.In African public health systems, Listeria monocytogenes is a pathogen of relatively low priority. Yet, the biggest listeriosis outbreak recorded to date occurred in Africa in 2018. This review highlights the factors that potentially impact L. monocytogenes transmission risks through African food value chains (FVCs). With the high rate of urbanisation, African FVCs have become spatially longer yet still informal. At the same time, dietary diversifications have resulted in increased consumption of processed ready-to-eat (RTE) meat, poultry, fishery and dairy products typically associated with a higher risk of L. monocytogenes consumer exposure. With frequent cold chain challenges, the potential of L. monocytogenes growth in contaminated RTE foods can further amplify consumer exposure risks. Moreover, the high prevalence of untreated HIV infections, endemic anaemia, high fertility rate and a gradually increasing proportion of elderly persons expands the fraction of listeriosis-susceptible groups among African populations. With already warmer tropical conditions, the projected climate change-induced increases in ambient temperatures are likely to exacerbate listeriosis risks in Africa. As precautionary approaches, African countries should implement systems for the detection and reporting of listeriosis cases and food safety regulations that provide L. monocytogenes standards and limits in high-risk RTE foods.The Australia-Africa Universities Network (AAUN)–Partnership Research and Development Fund 2018.https://ifst.onlinelibrary.wiley.com/journal/13652621Consumer ScienceFood ScienceSDG-02:Zero HungerSDG-03:Good heatlh and well-bein

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

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

Elimination of Escherichia coli O157:H7 from Alfalfa Seeds through a Combination of High Hydrostatic Pressure and Mild Heat▿

Escherichia coli O157:H7 has been associated with contaminated seed sprout outbreaks. The majority of these outbreaks have been traced to sprout seeds contaminated with low levels of pathogens. Sanitizing sprout seeds presents a unique challenge in the arena of produce safety in that even a low residual pathogen population remaining on contaminated seed after treatments appears capable of growing to very high levels during sprouting. In this study, the effectiveness of high-pressure treatment in combination with low and elevated temperatures was assessed for its ability to eliminate E. coli O157:H7 on artificially contaminated alfalfa seeds. Inoculated seed samples were treated at 600 MPa for 2 min at 4, 20, 25, 30, 35, 40, 45, and 50°C. The pressure sensitivity of the pathogenic bacteria was strongly dependent on the treatment temperature. At 40°C, the process was adequate in eliminating a 5-log-unit population on the seeds with no adverse effect on seed viability. Three treatments carried out at reduced pressure levels and/or extended treatment time, 550 MPa for 2 min at 40°C, 300 MPa for 2 min at 50°C, and 400 MPa for 5 min at 45°C, were equally lethal to the pathogen. When all three treatments were compared in terms of their impact on seed viability, the process of 550 MPa for 2 min at 40°C was the most desirable, achieving final germination percentages and sprout sizes statistically similar to those of control untreated seeds (P > 0.05)

Assessment of the Microbial Safety and Quality of Eggs from Small and Large-Scale Hen Breeders

ABSTRACT Egg is considered a nutritionally complete food and an excellent source of protein. The objectives of this study were (i) to assess the level of hygienic practices in small and large scale hen breeders, (ii) to evaluate the microbiological safety and quality of eggs along the production chain and (iii) to compare the shelf-life of eggs stored at ambient and refrigerated temperatures. The post-laying hygienic practices of farmers were assessed by a survey. Eggs obtained at post-laying and at retail were microbiologically analyzed for TVC, Salmonella, Staphylococcus and Yeasts and Molds. Eggs were also stored at ambient (ca. 22°C) or chilled temperature (4 ± 1°C) over a period of 23 days and analyzed every 6 days. Parameters tested included TVC, yolk index, Haugh unit and pH of the albumen. The survey revealed that neither small nor large-scale hen breeders washed the eggs before sale; however inspection for cracks and dry removal of dirt on egg surfaces were performed. The mean population of TVC, Staphylococcus spp. and Yeasts and Molds just after laying was ca. 4.6, 3.1 and 2.8 log cfu/g (egg shell) and 3.1, 2.5 and &lt; 1.0 log cfu/g (egg content) respectively and ca. 4.8, 4.6 and 3.5 log cfu/g (egg shell) and 3.2, 3.0 and &lt;1 log cfu/g (egg content) at retail. No Salmonella was detected on either egg shell or content at the post-laying and retail stages. Storage of shell eggs at ambient storage resulted in a decrease in the yolk index and Haugh unit and an increase in the pH of the albumen as well as a significant increase in the TVC (P&lt;0.05). Findings from this study indicated that the microbiota of eggs increased steadily along the farm-to-kitchen continuum and highlight the importance of chilled storage to preserve egg freshness

Antimicrobial Activity of Hydrogen Peroxide for Application in Food Safety and COVID-19 Mitigation: An Updated Review

Hydrogen peroxide (H2O2) is a well-known agent with a broad-spectrum antimicrobial activity against pathogenic bacteria, fungi, and viruses. It is a colorless liquid and commercially available in aqueous solution over a wide concentration range. It has been extensively used in the food industry by virtue of its strong oxidizing property and its ability to cause cellular oxidative damage in microbial cells. This review comprehensively documents recent research on the antimicrobial activity of H2O2 against organisms of concern for the food industry, as well as its effect against SARS-CoV-2 responsible for the COVID-19 pandemic. In addition, factors affecting the antimicrobial effectiveness of H2O2, different applications of H2O2 as a sanitizer or disinfectant in the food industry as well as safety concerns associated with H2O2 are discussed. Finally, recent efforts in enhancing the antimicrobial efficacy of H2O2 are also outlined