Antibiotic resistance patterns of Staphylococcus aureus and Enterobacteriaceae isolated from street foods in selected towns of Ethiopia.

BACKGROUND: Street foods are any foods or drinks prepared or sold by street vendors in an open space. The purpose of this study was to determine the Bacteriological safety and antibiotic resistance patterns of Staphylococcus aureus and Enterobacteriaceae isolated from street foods. METHOD: A laboratory-based cross-sectional study was used from December 2022 to February 2023 on street foods of Addis Ababa, Hawassa, Dire Dawa, and Jimma towns of Ethiopia. 525 street foods and 175 water samples were taken from 175 street food vending stalls. Proportional allocation to the total town population and stratified sampling techniques were used to select vending stalls. Samples were analyzed for the presence of bacteria following the standard microbiological methods used for the isolation, enumeration, and identification of bacteria. Pour plate technique was used to transfer the suspension to MacConkey agar, Mannitol Salt Agar, and Salmonella Shigella Agar. The antibiotic susceptibility test was performed using the Kirby-Bauer disk diffusion method. SPSS software was used to analyze the data. RESULT: Out of 525 food samples, 279 (53%) were contaminated by bacteria. From 175 water samples, 95 (54.3%) were contaminated with Escherichia coli. From both samples in total, eleven bacterial species were isolated. Staphylococcus aureus was the most frequently isolated species. Shigella, Klebsiella, and Salmonella group A have statistically significant with the type of food. Erythromycin (54%), Streptomycin (17%), and Amoxicillin (14%) were the most resistant antibiotics. Least resistance was observed to Ciprofloxacin (5%). CONCLUSION: Street foods of the selected towns were highly contaminated with various antibiotic-resistant organisms. Hence, the relevant authorities ought to ensure the proper handling of street food by enforcing safety measures. Additionally, they should initiate a widespread awareness campaign promoting the prudent use of antibiotics among both street food vendors and the broader population.

Which domestic refrigerator temperatures in Europe? - Focus on shelf-life studies regarding Listeria monocytogenes (Lm) in ready-to-eat (RTE) foods.

Listeria monocytogenes (Lm) is a pathogenic bacteria able to grow at refrigerated temperatures, widely distributed in the environment. This bacteria is susceptible to contaminate various food products of which refrigerated ready-to-eat foods (RTEF) may pose a risk for public health. In Europe, food business operators (FBOs) shall ensure that foodstuffs comply with the relevant microbiological criteria set out in the Regulation (EC) N°2073/2005. Food safety criteria for Lm are defined in RTEF throughout their shelf-life. FBOs should implement studies to demonstrate that the concentration of Lm does not exceed 100 CFU/g at the end of the shelf-life, taking into account foreseeable conditions of distributions, storage and use, including the use by consumers. However, this last part of the cold chain for food products is the most difficult to capture and control. For this purpose, the European Union Reference Laboratory for Lm (EURL Lm) launched an inquiry to its National Reference Laboratory network and reviewed the scientific literature from 2002 to 2020. The outcomes were integrated in the technical guidance document of the EURL Lm to assess shelf-life of RTEF which resulted in the recommendation to use 10 °C as the reference temperature to simulate the reasonably foreseen storage conditions in domestic refrigerators.

Prevalence, Antibiotic Resistance, and Molecular Typing of Staphylococcus aureus Isolated from Ready-to-Eat Foods in Guangdong, South China.

The increasing global popularity of ready-to-eat (RTE) foods for their convenience simultaneously brings along a risk, as these products can be contaminated with various microorganisms, including potentially harmful pathogens. We aimed to investigate the food contamination of Staphylococcus aureus (S. aureus) in RTE foods in Guangdong, South China. All S. aureus isolates were subjected to characterization through antimicrobial susceptibility tests, multilocus sequence typing (MLST), and PCR analysis for detecting mec and blaZ genes. A total of 824 RTE food samples were collected from 2017 to 2022, of which 73 (8.9%) were found to be contaminated with S. aureus. Contamination levels were mostly in the range of 0.3-1.0 most probable number (MPN)/g, with 10 samples exceeding 110 MPN/g. Of the 73 S. aureus isolates, 10 were identified as methicillin-resistant S. aureus (MRSA). In MRSA, resistance was most frequently observed to penicillin (100%, 10/10), followed by erythromycin (80.0%, 8/10) and tetracycline (70%, 7/10). And in methicillin-sensitive S. aureus (MSSA), resistance was most frequently observed to penicillin (98.4%, 62/63), followed by tetracycline (30.2%, 19/63) and erythromycin (23.8%, 15/63). Overall, 98.6% (72/73) of the isolates demonstrated resistance to at least one antimicrobial agent, whereas 31.5% (23/73) were resistant to three or more antimicrobials. Fifty-seven S. aureus isolates harbored the penicillin-resistant gene blaZ, and 10 isolates carried the mec gene. In addition, 30.1% of the isolates harbored genes for classical staphylococcal enterotoxins (SEs), with seb being the most frequently detected SE gene. MLST revealed that the 73 isolates belonged to 14 different sequence types (STs), the most prevalent of which was ST7. In MRSA, the most common prevalent clone is ST6, and in MSSA, ST7 was the most common isolates. The prevalent multidrug resistance indicates that the resistance situation of foodborne S. aureus in Guangdong is severe, posing a potential threat to consumer safety and health.

Role of dehydration technologies in processing for advanced ready-to-eat foods: A comprehensive review.

Advanced ready-to-eat foods, which can be consumed directly or only need simple processed before consumption, refer to the products that processing with cutting-edge food science and technology and have better quality attribute. Cold chain and chemical addition are commonly used options to ensure microbial safety of high moisture advanced ready-to-eat foods. However, this requires freezing/thawing processing at high cost or has undesirable residue. Dehydration treatment has the potential to compensate those shortcomings. This article reviewed the positive effects of dehydration on advanced ready-to-eat foods, current application status of dehydration technologies, novel dehydration related technologies and the pathogenic bacteria control of products. It is observed that dehydration treatment is receiving increasing attention for ready-to-eat foods including space foods, 3 D-printed personalized foods and formula foods for special medical purposes. Recently developed drying technologies such as pulsed spouted microwave freeze-drying and infrared freeze-drying have attracted much interest due to their excellent drying characteristics. Finally, intelligent drying, dehydration-nano-hybridization and dehydration-induced multi-dimensional modification technology are some of the emerging R and D areas in this field.

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).

Listeria monocytogenes survives better at lower storage temperatures in regular and low-salt soft and cured cheeses.

The behaviour of Listeria monocytogenes was investigated in soft pasteurized milk cheese elaborated with different salt concentrations (1.17 and 0.30% w/w) and in cured raw sheep milk cheese over storage up to 189 days at different isothermal conditions. Commercial 25-g cheese samples were inoculated with a 4-strain cocktail of L. monocytogenes (serovars 4b, 1/2a, 1/2b and 1/2c) at approximately 104 CFU/g. The inoculated samples were stored at 4 and 22 °C and withdrawn at proper intervals for L. monocytogenes enumeration. The prevalence of the different serovar strains of L. monocytogenes was characterized on soft cheese samples over storage at 4 °C using multiplex PCR. Salt reduction did not affect the survival of L. monocytogenes in soft cheeses and a maximum of 1-log reduction was observed in both regular and low-salt cheeses after 189 days of storage at 4 °C. The pathogen showed greater survival capacity in both soft and cured cheeses during storage at 4 °C compared to the storage at 22 °C, where more than 2.5 log reductions were computed. The fate of L. monocytogenes was described through a Weibull model fitted to survival data. The time required for a first tenfold reduction of the L. monocytogenes population (δ) at 4 °C is around 150 days in soft and 72 days in cured cheeses. At 22 °C, the estimated δ values are at least 60% lower in both cheese types. Among the four L. monocytogenes serovars present in the inoculated cocktail, the serovar 4b strain was the most sensitive to refrigerated storage, while the prevalence of serovar 1/2c strain increased over time in soft cheeses. Overall, the data obtained in this study help to deepen knowledge into factors affecting L. monocytogenes behaviour on cheeses and evidenced the variability between serovars in terms of survival capacity, which may be considered when performing microbial risk assessments.

Physicochemical Parameters Affecting Norovirus Adhesion to Ready-To-Eat Foods.

The adhesion of noroviruses to strawberry, turkey slices, ham, and cheddar cheese was studied using murine norovirus 1 (MNV-1) as a surrogate for human norovirus (NoV). Based on plaque assay, the recovery and adhesion of MNV-1 depended on the food type (turkey versus strawberry), pH of the initial suspension buffer (pH 4 versus pH 7), and food fat composition (C8 versus C18). Recovery of infectious particles from turkey was 68% compared to 9.4% from strawberry. On turkey, adhesion of MNV-1 was lower at pH 7 (pH of fecal matter), and virus particles adhered to this pH were recovered more easily (33,875 PFU) than at pH 4 (pH of vomitus). The presence of fat and the composition of fatty acids seemed to increase MNV-1 recovery and adherent viral particles recovered but did not affect adhesion (68% on fat-free turkey and regular turkey). Adherent MNV-1 particles recovered from stainless steel coated with saturated fatty acid (C8, C14, C18) increased significantly with chain length (P < 0.05), but adhesion did not seem to change. Using liquid droplet contact angle to measure surface energy, it was deduced that hydrophobic interactions contribute considerably to the adhesion of MNV-1 to stainless steel, polyvinyl chloride, and high-density polyethylene. IMPORTANCE Ready-to-eat (RTE) foods are major vehicles of transmission of foodborne viral pathogens, including NoV. The high incidence of gastroenteritis caused by viruses is due largely to their persistence in the environment and adhesion to different kinds of surfaces in the food industry, including the foods themselves. Compared with bacteria, adhesion of viruses to surfaces is poorly understood. Better knowledge of the physicochemical parameters involved in the adhesion of NoV to ready-to-eat foods is essential to devising effective strategies for reducing the persistence and, thus, the transmission of this virus.

Association between the consumption of ultra-processed foods and the practice of breast-feeding in children under 2 years of age who are beneficiaries of the conditional cash transfer programme, Bolsa Família.

OBJECTIVE: To evaluate the association between the consumption of ultra-processed foods (UPF) and the practice of breast-feeding in children under 2 years of age assisted by the conditional cash transfer programme, Bolsa Família Programme (PBF). DESIGN: A cross-sectional study. The consumption of UPF and the practice of breast-feeding were assessed using a structured 24-h recall. Associations were calculated using hierarchical Poisson regression, adjusted at the last level by socio-economic, demographic and environmental variables from previous hierarchical levels. SETTING: Six counties from the state of Alagoas, Brazil. PARTICIPANTS: Children aged 6-24 months, assisted by PBF. RESULTS: A total of 1604 children were evaluated, 11·7% of whom were overweight, and most had consumed UPF (90·6%) in the last 24 h. The most consumed UPF were biscuits, chocolate milk and baby food with 74·8, 66·8 and 24·9%, respectively. Through multivariable analysis, an association was found between lower consumption of UPF in the continuation of breast-feeding until the second year of life (prevalence ratio (PR) 0·91, 95 % CI 0·86, 0·96) and in the first year of life (PR 0·93, 95 % CI 0·88, 0·99). CONCLUSIONS: It was found that the studied population had a high consumption of UPF, which harmed continued breast-feeding. We highlight the importance of strengthening public policies aimed at the promotion, protection and support of breast-feeding and healthy complementary feeding aimed at populations that have difficulties in physical and economic access to a healthy and adequate diet.

Bacterial contaminants and their antibiotic susceptibility patterns in ready-to-eat foods vended in Ogun state, Nigeria.

Contamination of ready-to-eat (RTE) foods by pathogenic bacteria may predispose consumers to foodborne diseases. This study investigated the presence of bacterial contaminants and their antibiotic susceptibility patterns in three locally processed RTE foods (eko, fufu and zobo) vended in urban markets in Ogun state, Nigeria. Bacteria isolated from a total of 120 RTE food samples were identified by 16S rRNA gene phylogeny while susceptibility patterns to eight classes of antibiotics were determined by the disc diffusion method. Species belonging to the genera Acinetobacter and Enterobacter were recovered from all RTE food types investigated, Klebsiella and Staphylococcus were recovered from eko and fufu samples, while those of Shigella were recovered from eko samples. Enterobacter hormaechei was the most prevalent species in all three RTE food types. Precisely 99% of 149 isolates were multidrug-resistant, suggesting a high risk for RTE food handlers and consumers. Co-resistance to ampicillin and cephalothin was the most frequently observed resistance phenotype. Results demonstrate that improved hygiene practices by food processors and vendors are urgently required during RTE processing and retail. Also, adequate food safety guidelines, regulation and enforcement by relevant government agencies are needed to improve the safety of RTE foods and ensure the protection of consumer health.

Brine Solution with Hydrocolloids Used to Enhance the Properties of Sterilized Meat.

RESEARCH BACKGROUND: Retort processing is one of the most widely used methods of thermal inactivation that provides convenient, ready-to-eat foods. Although this technology remains widespread, it can be revamped through processing of novel ingredients such as gums. This article aims to investigate the effect of the hydrocolloids collagen, soy protein isolate, carrageenan and modified starch with different salt mass fractions on the retorted meat products. EXPERIMENTAL APPROACH: Firstly, solutions of the added hydrocolloids of different salt mass fractions in order to stimulate the salting-in effect were studied. Lipid oxidation, syneresis and water activity were analysed during shelf life to find the best overall treatments. Lastly, sensory and texture analyses were then performed to assess the impact of the added hydrocolloids. RESULTS AND CONCLUSIONS: Yield, cooking loss and water-holding capacity had better results when higher salt mass fractions with hydrocolloids were used. The physicochemical results distinguished collagen from the other tested hydrocolloids. Syneresis remained in similar ranges regardless of the treatment. No difference was observed in water activity either. However, sterilization, vacuum sealing and the addition of a hydrocolloid contributed to low oxidation levels in all treatments. Lastly, sensory, texture and shear force analyses confirmed that the products with collagen were harder and firmer than the control samples, which explains the preference of control samples by the panellists. Nevertheless, assessors did not perceive the presence of collagen. NOVELTY AND SCIENTIFIC CONTRIBUTION: Physicochemical and sensory characteristics of the retorted meat can be considerably improvedwhen brine and hydrocolloids are combined with the retort technology.

Declaration of nutrition information on and nutritional quality of Thai ready-to-eat packaged food products.

OBJECTIVE: The present study assessed the nutrition information displayed on ready-to-eat packaged foods and the nutritional quality of those food products in Thailand. DESIGN: In March 2015, the nutrition information panels and nutrition and health claims on ready-to-eat packaged foods were collected from the biggest store of each of the twelve major retailers, using protocols developed by the International Network for Food and Obesity/Non-communicable Diseases Research, Monitoring and Action Support (INFORMAS). The Thai Nutrient Profile Model was used to classify food products according to their nutritional quality as 'healthier' or 'less healthy'. RESULTS: In total, information from 7205 food products was collected across five broad food categories. Out of those products, 5707 (79·2 %), 2536 (35·2 %) and 1487 (20·6 %) carried a nutrition facts panel, a Guideline Daily Amount (GDA) label and health-related claims, respectively. Only 4691 (65·1 %) and 2484 (34·5 %) of the products that displayed the nutrition facts or a GDA label, respectively, followed the guidelines of the Thai Food and Drug Administration. In total, 4689 products (65·1 %) could be classified according to the Thai Nutrient Profile Model, of which 432 products (9·2 %) were classified as healthier. Moreover, among the 1487 products carrying health-related claims, 1219 (82·0 %) were classified as less healthy. Allowing less healthy food products to carry claims could mislead consumers and result in overconsumption of ready-to-eat food products. CONCLUSIONS: The findings suggest effective policies should be implemented to increase the relative availability of healthier ready-to-eat packaged foods, as well as to improve the provision of nutrition information on labels in Thailand.

Consumption of junk foods by school-aged children in rural Himachal Pradesh, India.

There has been an increase in the consumption of junk food (JF) among school-aged children (SAC) possibly leading to obesity and diet-related diseases among them. We do not have evidence on consumption of JF in rural areas; hence, we conducted a study to assess the consumption of JF by SAC in rural, Himachal Pradesh. A total of 425 children in the age group of 12-18 years studying in 30 government schools (clusters) were included. The clusters were selected using population proportionate to size sampling methodology. We found high prevalence (36%) of consumption of JF among SAC during the last 24 h. Efforts should be taken to reduce the consumption of JF by promotion of healthy dietary habits and educating children about the ill effects of JF.

Microbiological quality of selected ready-to-eat leaf vegetables, sprouts and non-pasteurized fresh fruit-vegetable juices including the presence of Cronobacter spp.

Bacteria of the genus Cronobacter are emerging food-borne pathogens. Foods contaminated with Cronobacter spp. may pose a risk to infants or adults with suppressed immunity. This study was aimed at determining the microbiological quality of ready-to-eat (RTE) plant-origin food products available on the Polish market with special emphasis on the prevalence of Cronobacter genus bacteria. Analyses were carried out on 60 samples of commercial RTE type plant-origin food products, including: leaf vegetables (20 samples), sprouts (20 samples) and non-pasteurized vegetable, fruit and fruit-vegetable juices (20 samples). All samples were determined for the total count of aerobic mesophilic bacteria (TAMB) and for the presence of Cronobacter spp. The isolates of Cronobacter spp. were subjected to genetic identification and differentiation by 16S rDNA sequencing, PCR-RFLP analysis and RAPD-PCR and evaluation of antibiotic susceptibility by the disk diffusion assay. The TAMB count in samples of lettuces, sprouts and non-pasteurized fruit, vegetable and fruit-vegetable juices was in the range of 5.6-7.6, 6.7-8.4 and 2.9-7.7 log CFU g-1, respectively. The presence of Cronobacter spp. was detected in 21 (35%) samples of the products, including in 6 (30%) samples of leaf vegetables (rucola, lamb's lettuce, endive escarola and leaf vegetables mix) and in 15 (75%) samples of sprouts (alfalfa, broccoli, small radish, lentil, sunflower, leek and sprout mix). No presence of Cronobacter spp. was detected in the analyzed samples of non-pasteurized fruit, vegetable and fruit-vegetable juices. The 21 strains of Cronobacter spp. isolated from leaf vegetable and sprouts included: 13 strains of C. sakazakii, 4 strains of C. muytjensii, 2 strains of C. turicensis, one strain of C. malonaticus and one strain of C. condimenti. All isolated C. sakazakii, C. muytjensii, C. turicensis and C. malonaticus strains were sensitive to ampicillin, cefepime, chloramphenicol, gentamycin, streptomycin, tetracycline, ciprofloxacin and cotrimoxazol, whereas the C. condimenti isolate showed intermediate resistance to streptomycin and cotrimoxazole.

The occurrence of Salmonella in raw and ready-to-eat bean sprouts and sprouted seeds on retail sale in England and Northern Ireland.

UNLABELLED: A total of 554 samples of bean sprouts or other sprouted seeds were collected at retail sale and submitted to nine Official Control Laboratories in England and Northern Ireland during January to March 2011. Samples (100 g) were tested for the presence of Salmonella using the EN ISO 6579:2002 method. Products labelled as ready-to-eat comprised 23% of the samples and 61% were labelled as raw or to-cook: the remaining 12% had no indication if the food was intended as ready-to-eat or ready-to-cook, and 4% were not recorded. Salmonella spp. were detected from four samples of mung-bean sprouts (0·7% of all the 554 samples) and all four isolates were confirmed as Salmonella enterica serovar Abaetetuba (11 : k : 1,5). Two of the samples where Salmonella was detected were sold as ready-to-eat (labelled 'rinse and serve' only): The remaining two were from samples labelled as ready-to-cook. SIGNIFICANCE AND IMPACT OF THE STUDY: Consumption of sprouted seeds have been associated with infections from a range of foodborne pathogens, particularly Salmonella and shigatoxin producing Escherichia coli (STEC). However, there is limited data (including that from EU monitoring) on foodborne pathogens in samples of this food type which are not associated with outbreaks of infection. Out of 554 raw and ready-to-eat bean sprouts and sprouted seeds sampled at retail, Salmonella spp. was detected from four samples. This study illustrated the potential of this product to be contaminated with a human pathogen and the importance of considering the intended use and preparation of specific food in assessing microbiological risks.

Ethiopian Street Foods: Working Conditions and Governance Perspectives. A Qualitative Study.

Introduction: Street foods are foods and beverages as either ready for direct consumption or minimally processed, prepared, and/or sold by vendors and handlers. The objective of this study was to explore the condition and governance of street foods in Ethiopia. Method: A qualitative exploratory study was employed from December 2022 to January 2023 in Addis Ababa, Hawassa, Dire Dawa, and Jimma, cities of Ethiopia. Twelve respondents comprised key informants from selected governmental sectors were interviewed. The purposive sampling method was used to recruit study participants. The number of participants interviewed was determined by the information saturation criterion, and data were collected at the interviewee's offices. Data were collected by using key informant interview technique and audio recorded. An interview guide was used to facilitate interviews and thematic analysis was employed. The Overall data management process was conducted using Atlas-ti V 8 software. Result: The result revealed there were 4 thematic areas these were street food vendors and vending process, policy content and implementation, integration and coordination of sectors, and the way forward. The street food vendors prepared their food in an insanitary manner, absence of common working places for the vendors, lack of due emphasis for the street food vendors in the national food and nutrition policy, lack of formalization and legalization of street food vendors, poor coordination among sectors and institutions work on street food governance, and weakness on the implementation of rules and regulations in controlling street food vendors were the prominent gaps that were identified in the policy. Conclusion: Though Ethiopia has a national food and nutrition policy, the policy doesn't adequately address the street food vending sector. Besides, it is not well communicated to the implementers resulting in poor policy implementation. Quantifying socio-economic benefits of street food vending activities in Ethiopia needs further investigation.

Kinetic and proteomic studies in milk show distinct patterns among major Listeria monocytogenes clones.

Listeria monocytogenes, a contaminant of raw milk, includes hypervirulent clonal complexes (CC) like CC1, CC4, and CC6, highly overrepresented in dairy products when compared to other food types. Whether their higher prevalence in dairy products is the consequence of a growth advantage in this food remains unknown. We examined growth kinetics of five L. monocytogenes isolates (CC1, CC4, CC6, CC9, and CC121) at 37 and 4 °C in ultra-high temperature (UHT) milk and raw milk. At 4 °C, hypovirulent CC9 and CC121 isolates exhibit better growth parameters in UHT milk compared to the hypervirulent CC1, CC4, and CC6 isolates. CC9 isolate in raw milk at 4 °C exhibited the fastest growth and the highest final concentrations. In contrast, hypervirulent isolates (CC1, CC4, and CC6) displayed better growth rates in UHT milk at 37 °C, the mammalian host temperature. Proteomic analysis of representative hyper- (CC1) and hypovirulent (CC9) isolates showed that they respond to milk cues differently with CC-specific traits. Proteins related to metabolism (such as LysA or different phosphotransferase systems), and stress response were upregulated in both isolates during growth in UHT milk. Our results show that there is a Listeria CC-specific and a Listeria CC-common response to the milk environment. These findings shed light on the overrepresentation of hypervirulent L. monocytogenes isolates in dairy products, suggesting that CC1 and CC4 overrepresentation in dairy products made of raw milk may arise from contamination during or after milking at the farm and discard an advantage of hypervirulent isolates in milk products when stored at refrigeration temperatures.

Quantum dots (QDs) attached magnetic beads (MBs) for on-chip efficient capture and detection of bacteria in ready-to-eat (RTE) foods.

In this study, we established a versatile and simple magnetic-assisted microfluidic method for fast bacterial detection. Quantum dots (QDs) were loaded onto magnetic beads (MBs) to construct performance enhanced on-chip capture of bacteria. Escherichia coli (E. coli), as a model bacterium was studied. CdSe QDs were deposited onto the surface of Fe3O4 MBs through layer-by-layer self-assembly to enhance the loading of antibodies (Abs). MBs functionalized with anti-E. coli antibody molecules in a micropillar-based microfluidic chip were utilized to capture E. coli, and matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) was used for characterization of captured bacteria. This method was found capable of specifically isolating E. coli within the range of 1.0 to 1.0 × 109 CFU/mL, having a detection limit (LOD) of 10 CFU/mL. The average similarity score among mass spectra for the bacterial capture obtained in independent experiments is calculated as 0.97 ± 0.01 (n = 3), which shows this work's excellent reproducibility for bacterial capture. Bacterial growth on ready-to-eat (RTE) foods during its time of storage was successfully monitored. The present protocol has promising potential for microbial control and pathogen detection in the food industry.

Consumer attitudes and perceptions towards chilled ready-to-eat foods: a multi-national study.

Understanding consumers' behavior and their handling of high-risk foods at home is essential for reducing the number of foodborne illnesses. This study shows the results of a cross-national analysis of consumers' perception from nine countries, and the identification of customers' clusters and its characteristics in order to understand customers' behavior, and to build safe chilled ready-to-eat (RTE) foods prevention strategies. The cluster analysis resulted in two clusters: (1) "Precautious consumers" characterized by the orientation towards pre-packed RTE foods, with consumers mainly coming from Bosnia and Herzegovina, India, Poland, Portugal, Spain, and Turkey. Their attitudes and self-reported practices may be categorized as less risky in terms of food-borne illnesses connected with the consumption of RTE foods; (2) "Unconcerned consumers" preferred cutting and slicing RTE foods freshly at the point of purchase, usually sold at the delicatessen department in a supermarket or at open markets. Those consumers mostly came from Croatia, Serbia and Slovenia and their attitudes and self-reported practices were riskier. These results allow a better understating of what characterizes consumers of RTE foods in different countries.

Survival of Salmonella enterica and Listeria monocytogenes in date palm paste and syrup at different storage temperatures.

This study aimed to investigate the behavior of Salmonella enterica and Listeria monocytogenes in processed date paste and syrup at different temperatures. Commercial products were inoculated with approximately 6 log CFU/mL of S. enterica or L. monocytogenes and stored at 4, 10, and 24°C for 90 days. S. enterica was able to survive in date products until the end of storage at 4°C. At this temperature, numbers decreased by 2.1 log CFU/g in date paste and by 3.4 log CFU/g in date syrup; however, at 10°C, cells were reduced >4.2 log CFU/g and were undetectable by direct plating in date paste or by enrichment (complete elimination) in syrup. Further, at 24°C, complete elimination of S. enterica was achieved in date paste and syrup by 30 and 7 days, respectively. L. monocytogenes numbers decreased by 1.4, 4.4, and >4.6 log CFU/g in date paste stored at 4, 10, and 24°C for 90 days, respectively. In date syrup, numbers of L. monocytogenes decreased to undetectable levels by 50, 14, and 4 days at 4, 10, and 24°C, respectively, by direct plating and complete elimination was observed at 10 and 24°C by 50 and 30 days of storage, respectively. The initial pH values of date paste and syrup were 4.7 and 4.8, respectively, and remained stable until the end of storage except for L. monocytogenes-inoculated syrup. PRACTICAL APPLICATION: Salmonella enterica and Listeria monocytogenes can easily survive in date paste and syrup particularly at refrigerator temperature, which explains the necessity of preventing the contamination of date products with foodborne pathogens.

Microbiological quality and antimicrobial resistance of Bacteria species recovered from ready-to-eat food, water samples, and palm swabs of food vendors in Accra, Ghana.

This study sought to investigate microbial quality and antimicrobial resistance of bacteria species from Ready-to-Eat (RTE) food, water, and vendor palm swab samples. Between 2019 and 2020, RTE food, water and vendor palm swab samples were collected from food vending sites in Accra, Ghana. Samples were cultured and confirmed using the Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF). Antimicrobial susceptibility testing (AST) was conducted using disk diffusion method. Beta-lactamase and Diarrheagenic Escherichia coli (DEC) genes were determined using Polymerase Chain Reaction (PCR). Total plate count (TPC) and Total coliform count (TCC) were performed on food and water samples. In total, 179 RTE food, 72 water and 10 vendor palm swab samples were collected. Enterobacter spp. (16.8 %), Citrobacter spp. (10.1 %), Enterococcus faecalis (7.8 %), Pseudomonas spp. (6.7 %) and Klebsiella pneumoniae (4.0 %) occurred in food. Isolates from water and palm were Klebsiella pneumoniae (20.8 %), Aeromonas spp. (16.7 %) and Enterobacter cloacae (11.1 %). Resistance to Amoxicillin-clavulanate, Tetracycline, Azithromycin, Sulfamethoxazole-trimethoprim, and Nitrofurantoin were common among Enterobacterales. High mean TPC and TCC showed in some RTE food and different water types used in vending depicting their unsafe condition for consumption and usage. The blaSHV and blaTEM genes were present in some Enterobacterales from food and water. The lt gene was identified in two food samples. AMR organisms associated with nosocomial infections in the samples investigated, calls for continuous surveillance in the food industry in Ghana. Also, the unsafe outcome of RTE food and water depicts the need for the enforcement of Ghana's food safety laws.