Microbial pollution and food safety

Determining the prevalence of Escherichia coli, Salmonella, and shiga toxin-producing Escherichia coli in manure of dairy lagoons

AIM

The aim of this study was to determine the prevalence of microbial pathogens in manure of dairy lagoons in California.

METHODS AND RESULTS

To determine pathogens in dairy manure stored in anaerobic lagoons of dairy farm, an extensive field study was conducted across California to sample manure from 20 dairy farms. Samples were analyzed to determine the prevalence of indicator Escherichia coli, Shiga toxin producing E. coli (STEC), Salmonella, and E. coli O157: H7. To test the E. coli, STEC, and Salmonella, we used agar culture-based method followed by polymerase chain reaction (PCR) method. In addition, a real- time PCR based method was used to determine the presence of E coli O157: H7. Study demonstrated that the prevalence of Salmonella in manure sample is lower than E. coli. The presence of Salmonella was found in 2.26% of the samples, and both the culture-based and PCR methods yielded comparable outcomes in detecting Salmonella. Moreover, ∼11.30% of the total samples out of the 177 were identified as positive for STEC by qPCR.

CONCLUSION

These findings demonstrate that indicator E. coli are abundantly present in anaerobic lagoons. However, the presence of STEC, and Salmonella is substantially low.

Microbiological quality of edible vegetable oils produced and marketed in Gondar City, Northwest Ethiopia

Edible oils are imported and produced in Ethiopia, notably in Gondar, and their production has expanded considerably in recent years. The expansion of locally produced edible vegetable oils with severe quality control, substandard edible oil production, and quality deterioration may contribute to the contamination of microbes, which may cause public health problems. This study determines the microbiological quality of edible vegetable oils being produced and marketed in Gondar City, Northwest Ethiopia, in 2021. A laboratory-based cross-sectional study design was conducted from May to July 2021 in Gondar City. A simple random sampling technique was used to collect 17 edible vegetable oil samples. Aseptically collected samples were analyzed in the microbiology lab room. The microbiological quality of vegetable oil was assessed using standard microbiological procedures and techniques. The collected data were entered into a Microsoft Excel 2016 spreadsheet and Stata Version 14. A non-parametric Kruskal-Wallis test was used to assess significant variation. Seventeen edible vegetable oil samples were examined and found to contain a varying number of bacteria, yeast, and molds. Staphylococcus aureus, Klebsiella Pneumoniae, and Pseudomonas aeruginosa were the identified bacteria, whereas Saccharomyces cerevisiae, Aspergillus niger, Aspergillus flavus, and Aspergillus fumigatus were the identified fungi. Total coliform and fecal coliform isolates were also identified in the oil samples. A level of microbial contamination that has public health importance was observed in some of the oil samples analyzed, and the isolated microorganisms indicate unhygienic handling, processing, and storage practices in the oil production and market sites. The introduction of strict rules, regulations, and updated manufacturing technologies and processes to ensure food safety and quality is needed.

Combining AI Tools with Non-Destructive Technologies for Crop-Based Food Safety: A Comprehensive Review

On a global scale, food safety and security aspects entail consideration throughout the farm-to-fork continuum, considering food's supply chain. Generally, the agrifood system is a multiplex network of interconnected features and processes, with a hard predictive rate, where maintaining the food's safety is an indispensable element and is part of the Sustainable Development Goals (SDGs). It has led the scientific community to develop advanced applied analytical methods, such as machine learning (ML) and deep learning (DL) techniques applied for assessing foodborne diseases. The main objective of this paper is to contribute to the development of the consensus version of ongoing research about the application of Artificial Intelligence (AI) tools in the domain of food-crop safety from an analytical point of view. Writing a comprehensive review for a more specific topic can also be challenging, especially when searching within the literature. To our knowledge, this review is the first to address this issue. This work consisted of conducting a unique and exhaustive study of the literature, using our TriScope Keywords-based Synthesis methodology. All available literature related to our topic was investigated according to our criteria of inclusion and exclusion. The final count of data papers was subject to deep reading and analysis to extract the necessary information to answer our research questions. Although many studies have been conducted, limited attention has been paid to outlining the applications of AI tools combined with analytical strategies for crop-based food safety specifically.

One Health Perspectives on Food Safety in Minimally Processed Vegetables and Fruits: From Farm to Fork

While food markets and food production chains are experiencing exponential growth, global attention to food safety is steadily increasing. This is particularly crucial for ready-to-eat products such as fresh-cut salads and fruits, as these items are consumed raw without prior heat treatment, making the presence of pathogenic microorganisms quite frequent. Moreover, many studies on foodborne illnesses associated with these foods often overlook the transmission links from the initial contamination source. The prevention and control of the dissemination of foodborne pathogens should be approached holistically, involving agricultural production, processing, transport, food production, and extending to final consumption, all while adopting a One Health perspective. In this context, our objective is to compile available information on the challenges related to microbiological contamination in minimally handled fruits and vegetables. This includes major reported outbreaks, specific bacterial strains, and associated statistics throughout the production chain. We address the sources of contamination at each stage, along with issues related to food manipulation and disinfection. Additionally, we provide potential solutions to promote a healthier approach to fresh-cut fruits and vegetables. This information will be valuable for both researchers and food producers, particularly those focused on ensuring food safety and quality.

Antibacterial Effects of Theaflavins against Staphylococcus aureus and Salmonella paratyphi B: Role of Environmental Factors and Food Matrices

This study aimed to investigate the effects of different environmental factors (temperature, pH, and NaCl) and food matrices (skimmed milk powder, lecithin, and sucrose) on the antibacterial activity of theaflavins (TFs) against Staphylococcus aureus (S. aureus) and Salmonella paratyphi B (S. paratyphi B). TFs showed a larger diameter of inhibition zone (DIZ, 12.58 ± 0.09 mm-16.36 ± 0.12 mm) value against S. aureus than that of S. paratyphi B (12.42 ± 0.43 mm-15.81 ± 0.24 mm) at the same concentration (2-10 mg/mL). When temperatures were 25-121 °C, the DIZ of TFs against both S. aureus and S. paratyphi B was not significantly different. As pH increased from 2 to 10, their DIZ values decreased significantly from 16.78 ± 0.23 mm to 13.43 ± 0.08 mm and 15.63 ± 0.42 mm to 12.18 ± 0.14 mm, respectively. Their DIZ values increased slightly as the NaCl concentration increased from 0.2 mol/L to 0.8 mol/L, while their DIZ values decreased significantly for skimmed milk powder concentrations in the range of 20-120 g/L. Regarding the concentrations of lecithin and sucrose were 2-12 g/L and 10-60 g/L, their DIZ values showed no significant change against S. paratyphi B, but an increased trend for S. aureus. Under the above different environmental factors and food matrices, TFs maintained excellent antibacterial activity against S. aureus and S. paratyphi B, providing a theoretical guidance for applying TFs as novel antibacterial additives in the food industry.

"Blockchain technology in food safety and traceability concern to livestock products"

Livestock products share more than fifteen percent of total agri-foods traded worldwide. A global increase in food demand has increased the risk to food safety. Improvements in food quality, cold chain transit, and preservation are required for safe livestock products. Though, the food safety and regulation authorities demand complete food traceability from farm to fork, but in traditional supply chain it is ignored by fiddling with the transit paperwork and bill invoices. The process of supply chain reformation and activities linked to food recalls during food safety issues are insanely expensive and challenging. Traceability-driven food supply chain management is likely to implement novel technologies like the Internet of Things (IoT). The capability of the Blockchain era within the food sector is emerging with use cases across different regions, as shown via the growing number of studies. Credibility, efficiency, and safety are all improved when food products can be instantly traced from their point of origin through all points of contact on their way to the consumer. Blockchain assures a tamper-proof and transparent system that allows an innovative business solution, together with smart contracts. However, there are significant difficulties with the implementation of blockchain technology for food traceability. It necessitates more and more training platforms as well as trainers, who can make understanding and operability of this technology easy among ground-level participants and food entities. For the tactical application of this technology, it is essential to comprehend the legal and regulatory framework.

Prevalence Estimation, Antimicrobial Susceptibility, and Serotyping of Salmonella enterica Recovered from New World Non-Human Primates (Platyrrhini), Feed, and Environmental Surfaces from Wildlife Centers in Costa Rica

Concern about zoonoses and wildlife has increased. Few studies described the role of wild mammals and environments in the epidemiology of Salmonella. Antimicrobial resistance is a growing problem associated with Salmonella that threatens global health, food security, the economy, and development in the 21st century. The aim of this study is to estimate the prevalence and identify antibiotic susceptibility profiles and serotypes of non-typhoidal Salmonella enterica recovered from non-human primate feces, feed offered, and surfaces in wildlife centers in Costa Rica. A total of 180 fecal samples, 133 environmental, and 43 feed samples from 10 wildlife centers were evaluated. We recovered Salmonella from 13.9% of feces samples, 11.3% of environmental, and 2.3% of feed samples. Non-susceptibility profiles included six isolates from feces (14.6%): four non-susceptible isolates (9.8%) to ciprofloxacin, one (2.4%) to nitrofurantoin, and one to both ciprofloxacin and nitrofurantoin (2.4%). Regarding the environmental samples, one profile was non-susceptible to ciprofloxacin (2.4%) and two to nitrofurantoin (4.8%). The serotypes identified included Typhimurium/I4,[5],12:i:-, S. Braenderup/Ohio, S. Newport, S. Anatum/Saintpaul, and S. Westhampton. The epidemiological surveillance of Salmonella and antimicrobial resistance can serve in the creation of strategies for the prevention of the disease and its dissemination throughout the One Health approach.

Socioeconomic impacts of COVID-19 pandemic on foodborne illnesses in the United States

Foodborne diseases continue to impact human health and the economy. The COVID-19 pandemic has dramatically affected the food system from production to consumption. This project aims to determine the impact of the COVID-19 pandemic on the spread of foodborne diseases and the factors that may have contributed, including environmental, behavioral, political, and socioeconomic. Data for this study were collected from The Foodborne Diseases Active Surveillance Network (FoodNet) for 2015-2020. FoodNet personnel located at state health departments regularly contact the clinical laboratories in Connecticut (CT), Georgia (GA), Maryland (MD), Minnesota (MN), New Mexico (NM), Oregon (OR), Tennessee (TN), and selected counties in California (CA), Colorado (CO), and New York (NY). Data were analyzed using SAS to determine the changes in rates of foodborne pathogens reported in FoodNet before and during the COVID-19 pandemic in the ten reporting states. Results of the study showed a significant decline in the incidences of foodborne diseases ranging between 25% and 60%. A geographical variation was also observed between California and states with the highest decline rate of foodborne illnesses. Policies and restrictions, in addition to environmental and behavioral changes during the COVID-19 pandemic, may have reduced rates of foodborne diseases.

Ecology and epidemiology of Salmonella spp. isolated from the environment and the roles played by wild animals in their maintenance

Salmonella is a ubiquitous organism of public health importance that causes diarrhea and other systemic disease syndromes. The ecology and epidemiology of the organism in addition to the roles played by wild animals are important in understanding its disease. Relevant published peer-reviewed literature was obtained after imputing the study's keywords into the Google search engine. The publications were thereafter saved for the study. The study revealed the ecology of Salmonella is directly related to its epidemiology. These were found to be either positively or negatively influenced by the living and non-living parts of the environment. Free-ranging and captive wild animals can serve as asymptomatic carriers of Salmonella, therefore, help to maintain the cycle of the disease since wildlife serves as reservoir hosts to over 70% of emerging zoonotic diseases. Cockroaches transmit Salmonella through their feces, and body parts and when ingested by birds and animals. The statistically significant over 83% of Salmonella isolation in lizards suggests the reptile could be a source of Salmonella distribution. Snakes, foxes, badgers, rodents, and raccoons have been reported to have Salmonella as a natural component of their gut with the ability to shed the organism often. The high occurrence (>45%) of diverse Salmonella serovars coupled with the fact that some of these animals were handled, kept as pets and consumed by man portends these animals as potential sources of transmission of the organism and the disease. The etiology and epidemiology of Salmonella are overtly affected by several environmental factors which also determine their survival and maintenance. The roles played by wild animals in the relationship, transmission, growth or interaction within and between Salmonella spp., the occurrence, prevalence, and distribution of the organism help maintain the organism in the environment. An understanding of the roles played by the different parts of the environment and wild animals in the ecology and epidemiology of Salmonella can help make informed decisions on the prevention and control of the diseases it causes. This review aimed to investigate the relationship between ecology, epidemiology, and environment, including the roles played by wild animals in the maintenance of the organism and its disease.

Smoothie Drinks: Possible Source of Resistant and Biofilm-Forming Microorganisms

Smoothie drinks are currently very popular drinks sold especially in fast food establishments. However, smoothies are a significant source of microorganisms. The aim of this study was to evaluate the microbiological quality of smoothies purchased in Eastern Bohemia. A higher prevalence of mesophilic aerobic bacteria (5.4-7.2 log CFU/mL), yeast (4.4-5.9 log CFU/mL) and coliform bacteria (3.1-6.0 log CFU/mL) was observed in vegetable smoothies, in which even the occurrence of enterococci (1.6-3.3 log CFU/mL) was observed. However, the occurrence of S. aureus, Salmonella spp. and Listeria spp. was not observed in any samples. Nevertheless, antimicrobial resistance was observed in 71.8% of the isolated strains. The highest level of resistance was found in isolates from smoothie drinks with predominantly vegetable contents (green smoothie drinks). Considerable resistance was observed in Gram-negative rods, especially to amoxicillin (82.2%) and amoxicillin with clavulanic acid (55.6%). Among enterococci, only one vancomycin-resistant strain was detected. The vast majority of isolated strains were able to form biofilms at a significant level, which increases the clinical importance of these microorganisms. The highest biofilm production was found in Pseudomonas aeruginosa, Kocuria kristinae and Klebsiella pneumoniae. Overall, significant biofilm production was also noted among isolates of Candida spp.

Environmental health and risk assessment metrics with special mention to biotransfer, bioaccumulation and biomagnification of environmental pollutants

The environment pollutants, which are landed up in environment because of human activities like urbanization, mining and industrializations, affects human health, plants and animals. The living organisms present in environment are constantly affected by the toxic pollutants through direct contact or bioaccumulation of chemicals from the environment. The toxic and hazardous pollutants are easily transferred to different environmental matrices like land, air and water bodies such as surface and ground waters. This comprehensive review deeply discusses the routes and causes of different environmental pollutants along with their toxicity, impact, occurrences and fate in the environment. Environment health and risk assessment tools that are used to evaluate the harmfulness, exposure of living organisms to pollutants and the amount of pollutant accumulated are explained with help of bio-kinetic models. Biotransfer, toxicity factor, biomagnification and bioaccumulation of different pollutants in the air, water and marine ecosystems are critically addressed. Thus, the presented survey would be collection of correlations those addresses the factors involved in assessing the environmental health and risk impacts of distinct environmental pollutants.

Time Domain (TD) Proton NMR Analysis of the Oxidative Safety and Quality of Lipid-Rich Foods

Food safety monitoring is highly important due to the generation of unhealthy components within many food products during harvesting, processing, storage, transportation and cooking. Current technologies for food safety analysis often require sample extraction and the modification of the complex chemical and morphological structures of foods, and are either time consuming, have insufficient component resolution or require costly and complex instrumentation. In addition to the detection of unhealthy chemical toxins and microbes, food safety needs further developments in (a) monitoring the optimal nutritional compositions in many different food categories and (b) minimizing the potential chemical changes of food components into unhealthy products at different stages from food production until digestion. Here, we review an efficient methodology for overcoming the present analytical limitations of monitoring a food's composition, with an emphasis on oxidized food components, such as polyunsaturated fatty acids, in complex structures, including food emulsions, using compact instruments for simple real-time analysis. An intelligent low-field proton NMR as a time domain (TD) NMR relaxation sensor technology for the monitoring of T₂ (spin-spin) and T₁ (spin-lattice) energy relaxation times is reviewed to support decision-making by producers, retailers and consumers in regard to food safety and nutritional value during production, shipping, storage and consumption.

Fecal indicator bacteria along multiple environmental exposure pathways (water, food, and soil) and intestinal parasites among children in the rural northwest Ethiopia

Background

Children in low-resource settings are exposed to multiple risk factors for enteropathogens. However, the probability of exposures may be different across exposure pathways. Accordingly, this study was conducted to assess environmental exposures of children to intestinal parasites in the east Dembiya district of Ethiopia.

Methods

A cross-sectional study was conducted for 372 households with children aged 24–59 months. The potential for external exposure of children to intestinal parasites was assessed by determining the presence of fecal indicator organism (Escherichia coli (E. coli)) in drinking water at point of use, ready-to-eat foods, and courtyard soil from children’s outdoor play areas. For internal exposure assessment, ova of parasites in stool samples was detected using wet mount and Kato-Katz techniques to estimate exposure to intestinal parasites. The external and internal exposure assessments were also complemented using questionnaire and spot-check observations to assess behaviors that result in high risk of exposure. Individual and community-level predictors of intestinal parasites were identified using a multilevel logistic regression model. Statistically significant variables were identified on the basis of adjusted odds ratio (AOR) with 95% confidence interval (CI) and p-value < 0.05.

Results

Ova of one or more intestinal parasites was detected among 178 (47.8%) (95% CI 42.8, 52.6%) of the children. The most common intestinal parasites were A. lumbricoides (20.7%) and S. mansoni (19.1%). Furthermore, E. coli was detected in 69.1% of drinking water samples at point of use, 67.5% of ready-to-eat food samples, and 83.1% of courtyard soil samples from children’s outdoor play areas. Exposure of children to intestinal parasites among children in the studied region was associated with poor hand hygiene of mothers (AOR 1.98, 95% CI (1.07, 3.66), poor hand hygiene of children (AOR 3.20, 95% CI (1.77, 5.77), mouthing of soil contaminated materials (AOR 2.31, 95% CI (1.26, 4.24), open defecation practices (AOR 2.22, 95% CI (1.20, 4.10), limited access to water (AOR 2.38, 95% CI (1.13, 5.01), water contamination (AOR 2.51, 95% CI (1.31, 4.80), food contamination (AOR 3.21, 95% CI (1.69, 6.09), and soil contamination (AOR 2.56, 95% CI (1.34, 4.90).

Conclusion

An extensive E. coli contamination of water, foods, and courtyard soil was found in the studied region and the potential sources of contamination were open defecation practices, unhygienic disposal of wastes, poor animal husbandry and keeping practices, and poor water and food safety measures at household level. Moreover, fecal contamination of water, foods, and soil linked to exposure of children to intestinal parasites in the studied region. Thus, it is critical to implement individual-level interventions (such as latrine utilization, hand hygiene promotion, food safety, home-based water treatment, and containment of domestic animals), plus community-level interventions (such as protecting water sources from contamination, source-based water treatment, and community-driven sanitation).

Microbial Quality and Safety of Raw Vegetables of Fiche Town, Oromia, Ethiopia

Vegetables contain vital ingredients such as minerals, phytochemicals, vitamins, and fibers, which play significant roles in human health. Consumption of fresh vegetables causes human infections and outbreaks while serving as a reservoir of several pathogens. The study evaluated the microbiological quality of raw vegetables consumed in and around Fiche town, Central Ethiopia. For the experimental study, a total of 100 samples of 5 different raw vegetables from two local markets were selected based on their commonalities for overall microbial quality in terms of aerobic mesophilic count, total coliform count, Enterobacteriaceae count, Staphylococci count, and yeast and mold levels. The highest count was aerobic mesophilic bacteria (5.7 log CFU/g) followed by Enterobacteriaceae (4.7 log CFU/g), while yeasts and molds count the least. The maximal count for aerobic mesophilic bacteria was enumerated in cabbage (6.4 log CFU/g) while the minimum was in green pepper samples (4.7 log CFU/g). Among 100 vegetable samples analyzed, 11% were contaminated by S. aureus which is highly prevalent in cabbage (20%), followed by lettuce (15%). In the present study, 15.0% of vegetable samples were positive for Salmonella and detected in all vegetable types.

Bacteroides Microbial Source Tracking Markers Perform Poorly in Predicting Enterobacteriaceae and Enteric Pathogen Contamination of Cow Milk Products and Milk-Containing Infant Food

Consumption of microbiologically contaminated food is one of the leading causes of diarrheal diseases. Understanding the source of enteric pathogens in food is important to guide effective interventions. Enterobacteriaceae bacterial assays typically used to assess food safety do not shed light on the source. Source-specific Bacteroides microbial source tracking (MST) markers have been proposed as alternative indicators for water fecal contamination assessment but have not been evaluated as an alternative fecal indicator in animal-derived foods. This study tested various milk products collected from vendors in urban Kenyan communities and infant foods made with the milk (n = 394 pairs) using conventional culture methods and TaqMan qPCR for enteric pathogens and human and bovine-sourced MST markers. Detection profiles of various enteric pathogens and Bacteroides MST markers in milk products differed from that of milk-containing infant foods. MST markers were more frequently detected in infant food prepared by caregivers, indicating recent contamination events were more likely to occur during food preparation at home. However, Bacteroides MST markers had lower sensitivity in detecting enteric pathogens in food than traditional Enterobacteriaceae indicators. Bacteroides MST markers tested in this study were not associated with the detection of culturable Salmonella enterica and Shigella sonnei in milk products or milk-containing infant food. The findings show that while Bacteroides MST markers could provide valuable information about how foods become contaminated, they may not be suitable for predicting the origin of the enteric pathogen contamination sources.

Trends in packaging material for food products: historical background, current scenario, and future prospects

The commercial demand for food products and dietary supplements has increased drastically in the last few decades. The packed food products and nutritional supplements have made a profound impact on the modern human lifestyle. Since ancient times, storage and long-term use of food products remain a significant challenge for humans. There are different parameters for the evaluation of food products and dietary supplements broadly categorized as quality control and quality assurance. On an average million tons of food, materials get spoiled daily worldwide due to lack of storage and transportation point out packaging systems inequalities. To ensure the quality of packed food products and nutritional supplements among available measures, packaging remained an important event and had been refined from time to time to provide a standard. Over a period, the packaging industry has evolved using modern technology from the conventional methods of new generation packaging, including glass, wood, and paper to most new biodegradable materials. The ancient pattern of packaging; manual packaging has been taken over by an automated system of packing, resulting in enhanced output with minimal chance of damage to valuable products for humanity. The article will emphasize new insights into current packaging system not only provide the quality of these products but also in aiming new heights beyond conventional technologies and consumer opinions. In the present study, we have given more emphasis on novel methods of packaging, the packaging materials, quality of packed products, and their impacts of food products on the environment.

Blastocystis occurrence and subtype diversity in wild European terrestrial mammals - The case of Białowieża Primeval Forest (NE Poland)

Blastocystis cf. Blastocystis hominis is the most common unicellular parasite found in human and animal intestines. Little is known about the life cycle, transmission and mechanisms of pathogenesis for this parasite. The aim of this study was to obtain new data on the genetic diversity of Blastocystis in selected species of mammals found in the Białowieża Primeval Forest (BPF), Poland, the best preserved lowland forest in temperate Europe. 113 faecal samples were collected in the period 2018–2020 from seven species of wild mammals occurring within the Polish part of BPF and its surroundings. Blastocystis was detected by molecular amplification and sequencing the small subunit rRNA gene. The overall prevalence of Blastocystis in animals was 8.9%. A larger number of stool samples (90) were collected from European bison and only for this species was it possible to calculate the prevalence of infection (5.6%). The isolates obtained from European bison were classified as ST1, ST3, ST5, ST7. Blastocystis was also detected in the grey wolf (Canis lupus) (ST5), wild boar (Sus scrofa) (ST5) and red deer (Cervus elaphus) (ST1). In conclusion, for the first time we have demonstrated the presence of Blastocystis in wild European bison. Preliminary studies have shown that Blastocystis is present in at least 4 species of wild mammals in the BPF area and that it exhibits great genetic diversity.

Blastocystis is present in wild mammals in the Białowieża Primeval Forest

Blastocystis in the Białowieża Primeval Forest exhibits great genetic diversity

Intra-species and interspecific transmission of Blastocystis in Białowieża Primeval Forest is highly probable.

Polymicrobial Interactions Operative during Pathogen Transmission

Pathogen transmission is a key point not only for infection control and public health interventions but also for understanding the selective pressures in pathogen evolution. The “success” of a pathogen lies not in its ability to cause signs and symptoms of illness but in its ability to be shed from the initial hosts, survive between hosts, and then establish infection in a new host. Recent insights have shown the importance of the interaction between the pathogen and both the commensal microbiome and coinfecting pathogens on shedding, environmental survival, and acquisition of infection. Pathogens have evolved in the context of cooperation and competition with other microbes, and the roles of these cooperations and competitions in transmission can inform novel preventative and therapeutic strategies.

Immobilization of Caraway Essential Oil in a Polypropylene Matrix for Antimicrobial Modification of a Polymeric Surface

This study investigates antibacterial polymer composites based on polypropylene as modified by caraway essential oil at various concentrations, the latter immobilized on a talc. The caraway essential oil is incorporated in the polypropylene by a thermoplastic processing method. Analysis of the morphology of the composites was carried out by scanning electron microscopy. The chemical composition of the caraway essential oil in addition to its efficiency of incorporation and release were evaluated by GC/MS and Pyrolysis-GC/MS techniques, respectively. Determination was made as to the influence of such incorporation on thermal and tensile properties of the samples, while antibacterial activity was evaluated through conducting disk diffusion tests and measurement with adherence to the ISO 22196:2011 standard. It was found that incorporating the caraway essential oil in the samples did not affect the homogeneity of the thermoplastic-processed composites at any studied concentration. Stress–strain analysis confirmed the plasticizing effect of the essential oil in the polypropylene matrix, in addition to which, differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) analysis revealed that the prepared compositions with essential oil exhibited similar thermal properties to neat polypropylene. Results indicated significant antibacterial activity against Staphylococcus aureus and Escherichia coli at the concentration of essential oil of 4.9 ± 0.2 wt% and higher.

Microbiological Safety of Food of Animal Origin from Organic Farms

The organic food sector and consumer interest in organic products are growing continuously. The safety and quality of such products must be at least equal to those of conventional equivalents, but attaining the same standards requires overcoming a particular problem identified in organic food production systems: the occurrence of bacterial pathogens such as Salmonella, Campylobacter, Listeria monocytogenes, Staphylococcus aureus and pathogenic Escherichia coli. These food-borne microorganisms were detected in the production environments of such food. The prevalence of pathogenic bacteria in organic livestock and products may be higher, but may also be the same as or lower than in like material from conventional farms. Furthermore, the incidence of antimicrobial-resistant bacteria was more often detected in conventional than in organic production. The aim of this review was to present the recent information on the microbiological safety of food of animal origin produced from raw materials from organic farms.

Comparison between the Real-Time PCR and Crystal Diagnostic Xpress Immunoassay Methods for Detecting Salmonella and Shiga Toxin-Producing Escherichia coli in the Air of Beef Slaughter Establishments

ABSTRACT

The aim of this study was to compare the effectiveness of a quantitative real-time PCR (qPCR) molecular method and the Crystal Diagnostic Xpress (CDx) immunoassay for detecting Salmonella and Shiga toxin-producing Escherichia coli (STEC) in air samples collected from abattoirs in Texas. The 70 air samples were collected from two small and two large meat processing plants in the spring and summer with a wetted wall cyclone air sampler. The samples were divided equally into two parts: one part was used for the qPCR assay, and the other part was enriched for 18 and 36 h and evaluated with the CDx immunoassay. All samples for which positive results were obtained were confirmed by plating and by biochemical and serological tests as recommended by AOAC International to verify results of rapid methods. With the qPCR and CDx assays and 36 h of enrichment, 37.5 and 57.1% of the samples, respectively, were positive for Salmonella (P < 0.05) and 65.0 and 60.7%, respectively, were positive for STEC (P > 0.05). Air samples required longer enrichment for the CDx immunoassay than recommended by the manufacturer for food samples. Recovery of Salmonella and STEC increased 16 and 47%, respectively, when enrichment was extended from 18 to 36 h. The prevalence of Salmonella and STEC obtained with both methods was affected by the size of the processing plant and the processing stage. Detection rates for samples from larger plants were higher for both pathogens. Significantly higher prevalence was obtained for samples from the stunning and dehiding areas than for those from the fabrication rooms and chillers. Salmonella detection was higher with the CDx assay than with the qPCR assay, but no differences were found for the detection of STEC by the qPCR and CDx assays. These results highlight the importance of method adjustments when testing matrices other than foods. More research is needed to understand the dynamics of pathogen dispersal in aerosols and how this affects the effectiveness of current rapid detection methods.

HIGHLIGHTS

Surface Wiping Test to Study Biocide -Cinnamaldehyde Combination to Improve Efficiency in Surface Disinfection

Disinfection is crucial to control and prevent microbial pathogens on surfaces. Nonetheless, disinfectants misuse in routine disinfection has increased the concern on their impact on bacterial resistance and cross-resistance. This work aims to develop a formulation for surface disinfection based on the combination of a natural product, cinnamaldehyde, and a widely used biocide, cetyltrimethylammonium bromide. The wiping method was based on the Wiperator test (ASTM E2967−15) and the efficacy evaluation of surface disinfection wipes test (EN 16615:2015). After formulation optimization, the wiping of a contaminated surface with 6.24 log₁₀ colony-forming units (CFU) of Escherichia coli or 7.10 log₁₀ CFU of Staphylococcus aureus led to a reduction of 4.35 log₁₀ CFU and 4.27 log₁₀ CFU when the wipe was impregnated with the formulation in comparison with 2.45 log₁₀ CFU and 1.50 log₁₀ CFU as a result of mechanical action only for E. coli and S. aureus, respectively. Furthermore, the formulation prevented the transfer of bacteria to clean surfaces. The work presented highlights the potential of a combinatorial approach of a classic biocide with a phytochemical for the development of disinfectant formulations, with the advantage of reducing the concentration of synthetic biocides, which reduces the potentially negative environmental and public health impacts from their routine use.

Microbial Contamination, an Increasing Threat to the Consumption of Fresh Fruits and Vegetables in Today's World

Microbes are found all over the globe with some few exceptions, including sterilized surfaces. They include normal flora that is nonpathogenic, which contribute to the larger percentage, and pathogenic species which are few. Hence, the activities of humans cannot be completely separated from microbes. Thus, many pathogenic microbes have found their way into fresh fruits and vegetables which are a great source of a healthy diet for humans. The growing demand for fresh fruits and vegetables has necessitated larger production. The larger production of vegetables within the shortest possible time to meet the growing demand has placed them at a higher risk of contamination with the pathogenic microbes, making the safety of consumers uncertain. Study of sources of contamination and type of pathogenic etiological agents isolated from fresh fruits and vegetables includes Bacillus cereus, Campylobacter jejuni, Clostridium botulinum, E. coli O157: H7, Listeria monocytogenes, Salmonella spp., Shigella, Staphylococcus, and Vibrio cholera. Several measures have proven to be effective in controlling contamination of microbes and they include the establishment of surveillance systems to monitor the production chain and thoroughly washing vegetables with vinegar water. Saltwater and other washing techniques are effective but caution should be taken to make sure one does not use one cycle of water for washing all vegetables. The consumption of fresh fruits and vegetables is still encouraged by this review but significant measures must be taken to check the safety of these products before consumption.