Food Manufacturing Environment Research Articles

Prospective modeling and estimating the epidemiologically informative match rate within large foodborne pathogen genomic databases

ObjectivesMuch has been written about the utility of genomic databases to public health. Within food safety these databases contain data from two types of isolates—those from patients (i.e., clinical) and those from non-clinical sources (e.g., a food manufacturing environment). A genetic match between isolates from these sources represents a signal of interest. We investigate the match rate within three large genomic databases (Listeria monocytogenes, Escherichia coli, and Salmonella) and the smaller Cronobacter database; the databases are part of the Pathogen Detection project at NCBI (National Center for Biotechnology Information).ResultsCurrently, the match rate of clinical isolates to non-clinical isolates is 33% for L. monocytogenes, 46% for Salmonella, and 7% for E. coli. These match rates are associated with several database features including the diversity of the organism, the database size, and the proportion of non-clinical BioSamples. Modeling match rate via logistic regression showed relatively good performance. Our prediction model illustrates the importance of populating databases with non-clinical isolates to better identify a match for clinical samples. Such information should help public health officials prioritize surveillance strategies and show the critical need to populate fledgling databases (e.g., Cronobacter sakazakii).

Susceptibility of Salmonella enterica Typhimurium dry surface biofilms to disinfection

AbstractIn food preparation and manufacturing environments, surfaces contaminated with Salmonella can lead to outbreaks of Salmonellosis. We hypothesise that Salmonella resides on dry surfaces in a biofilm form leading to potential environmental persistence and transfer following contact. This is the first study reporting that Salmonella Typhimurium can form dry surface biofilm (DSB). Six disinfectants commonly used in the food industry were evaluated for their efficacy against the DSB. The two most efficacious formulations reduced bacterial viability in DSB by >99.99% when combined with mechanical removal (5 sec wiping; 300 g weight). Five out of six formulations significantly reduced bacterial transfer when combined with wiping. Complete eradication of Salmonella Typhimurium DSB was challenging, and mechanical removal was essential to produce a >99.99% reduction in bacterial viability within DSB. This study highlights a potential mode of survival of Salmonella Typhimurium on food‐contact surfaces and DSB challenges for disinfection.

Listeria spp. transfers further from boots and wheels across flooring surfaces, compared with Salmonella, in the dairy context

Listeria spp. and Salmonella are important foodborne pathogens to control; their likely dissemination on floor material in dairy processing plants via contaminated vectors, like manufacturing boots and trolley wheels, and in two matrix types (reconstituted skim milk and yoghurt) was therefore evaluated. The types of microorganisms present, matrices, and vectors all statistically significantly impacted the relationship between steps/wheel rotations and the resulting concentration of bacteria transferred. Trolley wheels were shown to transfer both pathogens over a greater distance than boots alone, based on a linear model; however, taking into account the median stride of an individual, operators wearing contaminated processing boots were estimated to disseminate Listeria further than Salmonella, particularly in a yoghurt matrix (550 m2). The dissemination of Listeria and Salmonella by movable vectors may account for the apparent re-occurrence of the same strains within food manufacturing environments that appear to be too distant from known harbourage niches.

Stress Adaptation Responses of a Listeria monocytogenes 1/2a Strain via Proteome Profiling.

Listeria monocytogenes is a foodborne pathogen that is ubiquitous and largely distributed in food manufacturing environments. It is responsible for listeriosis, a disease that can lead to significant morbidity and fatality in immunocompromised patients, pregnant women, and newborns. Few reports have been published about proteome adaptation when L. monocytogenes is cultivated in stress conditions. In this study, we applied one-dimensional electrophoresis and 2D-PAGE combined with tandem mass spectrometry to evaluate proteome profiling in the following conditions: mild acid, low temperature, and high NaCl concentration. The total proteome was analyzed, also considering the case of normal growth-supporting conditions. A total of 1,160 proteins were identified and those related to pathogenesis and stress response pathways were analyzed. The proteins involved in the expression of virulent pathways when L. monocytogenes ST7 strain was grown under different stress conditions were described. Certain proteins, particularly those involved in the pathogenesis pathway, such as Listeriolysin regulatory protein and Internalin A, were only found when the strain was grown under specific stress conditions. Studying how L. monocytogenes adapts to stress can help to control its growth in food, reducing the risk for consumers.

Substituting Allose as the Primary Carbon Source During Enrichment Helps Improve Detection and Isolation of Lineage II Listeria monocytogenes From Food

Testing of foods for low levels of the human pathogen, Listeria monocytogenes (Lm), involves a selective enrichment procedure. A nonpathogenic species of Listeria, L. innocua (Li), is often present in foods and food-manufacturing environments and is an interference organism for Lm detection due to competition during enrichment. The present study investigated whether a novel enrichment strategy incorporating the sugar allose into the secondary enrichment broth (allose method) could improve the detection of Lm from foods when Li is present. First, Canadian food isolates of Listeria spp. were tested to confirm recent reports that lineage II Lm (LII-Lm), but not Li, could metabolize allose. All LII-Lm isolates (n = 81), but not Li (n = 36), possessed the allose genes lmo0734-lmo0739, and could efficiently metabolize allose. Next, smoked salmon was contaminated with mixtures of LII-Lm and Li and tested using different enrichment procedures to compare the ability to recover Lm. Allose broth was more effective than Fraser Broth, with Lm detected in 87% (74 of 85) compared to 59% (50 of 85) of the samples (P < 0.05), following a common preenrichment. When evaluated against a current Health Canada method (MFLP-28), the allose method was more effective, with LII-Lm detected in 88% (57 of 65) compared to 69% (45 of 65) of the samples (P < 0.05). The allose method also remarkably increased the ratio of LII-Lm to Li postenrichment, which improved the ease of obtaining isolated Lm colonies for confirmation tests. Allose may therefore provide a tool for use when the presence of background flora interferes with Lm detection. As this tool is specifically applicable to a subset of Lm, the use of this method modification may provide a working example of tailoring methodology to target the known subtype of the pathogen of interest in an outbreak investigation, or for regular monitoring activities in conjunction with a PCR screen for allose genes on preenrichment cultures.

Temperature, Time, and Type, Oh My! Key Environmental Factors Impacting the Recovery of Salmonella Typhimurium, Listeria monocytogenes, and Tulane Virus from Surfaces

Environmental monitoring (EM) programs are designed to detect the presence of pathogens in food manufacturing environments, with the goal of preventing microbial contamination of food. Nevertheless, limited knowledge exists regarding the influence of environmental conditions on microbial recovery during EM. This study uses a commercially available polyurethane foam EM tool to determine the influence of environmental factors on the recovery of foodborne pathogens. The specific objectives of this study were to determine if environmental conditions and surface composition impact the recovery of sought-after microorganisms found in food processing environments. These data are compared across (i) microorganism type, (ii) surface type, (iii) environmental temperature and relative humidity (RH), and (iv) exposure time. Two bacteria (Listeria monocytogenes and Salmonella Typhimurium) and one human norovirus surrogate (Tulane virus) were inoculated onto three nonporous surfaces (polypropylene, stainless steel, and neoprene). Surfaces were held in an environmental chamber for 24 or 72 h at 30°C with 30% RH, 6°C with 85% RH, and 30°C with 85% RH. Data indicate that microbial recovery from environmental surfaces significantly (P ≤ 0.05) varies by microorganism type, environmental conditions, and exposure time. For instance, all microorganisms were significantly different from each other, with the greatest mean log reduction being Tulane virus and the lesser reduction being L. monocytogenes at 4.94 ± 1.75 log PFU per surface and 2.54 ± 0.91 log CFU per surface, respectively. Overall, these data can be used to improve the effectiveness of EM programs and underscores the need to better comprehend how EM test results are impacted by food manufacturing environmental conditions.

Listeria prevention

<i>Listeria</i> prevention

An Exploration of Listeria monocytogenes, Its Influence on the UK Food Industry and Future Public Health Strategies.

Listeria monocytogenes is a Gram-positive intracellular pathogen that can cause listeriosis, an invasive disease affecting pregnant women, neonates, the elderly, and immunocompromised individuals. Principally foodborne, the pathogen is transmitted typically through contaminated foods. As a result, food manufacturers exert considerable efforts to eliminate L. monocytogenes from foodstuffs and the environment through food processing and disinfection. However, L. monocytogenes demonstrates a range of environmental stress tolerances, resulting in persistent colonies that act as reservoirs for the reintroduction of L. monocytogenes to food contact surfaces and food. Novel technologies for the rapid detection of L. monocytogenes and disinfection of food manufacturing industries have been developed to overcome these obstacles to minimise the risk of outbreaks and sporadic cases of listeriosis. This review is aimed at exploring L. monocytogenes in the UK, providing a summary of outbreaks, current routine microbiological testing and the increasing awareness of biocide tolerances. Recommendations for future research in the UK are made, pertaining to expanding the understanding of L. monocytogenes dissemination in the UK food industry and the continuation of novel technological developments for disinfection of food and the food manufacturing environment.

ASSESSING THE MICROBIOLOGICAL QUALITY AND SAFETY OF BIOFILM FORMING MICROORGANISMS FROM SELECTED FOODS IN ULI CAMPUS

Biofilms are complex microbial ecosystems formed by one or more species immersed in an extracellular matrix of different compositions depending on the type of food manufacturing environment and the colonizing species. Food-borne diseases associated with bacterial biofilms may arise via intoxications or infections. The main aim of this work is to isolate and identify microorganisms present in some selected food borne pathogens that forms biofilms, investigate for bacterial and fungal contamination and conduct antibiotic sensitivity testing on the bacterial isolates. Biofilm forming microorganisms was isolated from some selected food samples and contact surface. The samples were cultured and sub-cultured to get pure isolates. Bacteria and fungi isolates were identified and characterized using various biochemical tests. Antibiotic susceptibility test was performed on the various bacterial isolates. Suspected microorganisms recovered from the tests were Staphylococcus spp., Salmonella enterica, Escherichia coli, Pseudomonas spp., Candida albicans, Aspergillus spp., and Penicillum spp. The antibiotic susceptibility profile of the bacterial isolates from food samples revealed that E. coli showed susceptibility to Tarivid (OFX) 10 mcg, Reflacine (PEF) 10 mcg, Ciproflox (CPX) 10 mcg, Gentamicine (CN) 10 mcg and Streptomycine (S) 30mcg. S. enterica showed susceptibility to Ciproflox (CPX), Gentamicine (CN) and Streptomicine (s). S. aureus showed susceptibility to Ciproflox (CPX), Streptomicine (s) and Gentamicine (CN) and P. aeruginosa was resistance to the antibiotics used. Many foodborne diseases have been found to be associated with biofilms. The source of contamination from the pathogens investigated could be from contamination of utensils by pathogens, contamination from butcher’s table and knives and from food processing industry. The investigation concluded that bacterial and fungal species associated with food contamination is found to be associated with biofilms.

Analyzing aggregate environmental monitoring data for Listeria spp. in frozen food manufacturing environments

Food processors face serious challenges due to the ubiquity and prevalence of Listeria monocytogenes in production and processing facilities. Environmental monitoring for Listeria within the industry is important and detection of Listeria spp. is often used as an indicator for the potential presence of L. monocytogenes in the food processing environment. Environmental monitoring data from the frozen food manufacturing industry was compiled and analyzed to evaluate the adequacy of current practices in mitigating risks of L. monocytogenes in the processing environment and to determine if there are trends that could be used to further refine industry practices. A method to collect anonymous data for analysis to build a strong aggregate data set from multiple facilities was used. Information included general descriptions of each facility and specific information about individual environmental monitoring test results from environmental zones 2–4, or nonfood contact surfaces. Information collected from facilities included the size of the facilities and how environmental monitoring samples were collected and analyzed. For each individual sample, information collected included the area or equipment sampled and the result of each sample. Descriptors were provided to allow for grouping of similar results. The data represents environmental monitoring samples that were collected between six months to a year prior to the beginning of this research. Twenty-seven facilities provided 42,799 environmental monitoring observations. Environmental zones 3 and 4 had a higher estimated marginal probability of Listeria positive results compared to zone two for routine environmental monitoring samples (p < 0.05). Pre-lethality and post-lethality production areas had a higher probability of Listeria positive results compared to lethality areas for all environmental samples (p < 0.05). Cold storage locations, i.e., coolers and freezers had a significantly higher probability for a Listeria positive result than noncold storage areas (p < 0.01). Applying statistical modeling and comparing estimated marginal probabilities of aggregate Listeria prevalence data from processing operations across the industry can provide information for guidance on focusing sanitation within processing operations to reduce risk related to L. monocytogenes. These data help to identify common themes in the industry and determine potential areas on which to focus when testing for prevalence of Listeria spp. within the food processing environment. This study serves as a useful baseline for continued improvement in environmental monitoring across all frozen food manufacturing facilities. • Environmental monitoring samples from frozen food facilities were collected. • Twenty-seven facilities provided 42,799 environmental monitoring observations. • Zones 3/4 had a higher probability of Listeria positive results compared to zone 2.

Combined Effect of Temperature and Relative Humidity on the Survival of Salmonella Isolates on Stainless Steel Coupons.

The survival on stainless steel of ten Salmonella isolates from food factory, clinical and veterinary sources was investigated. Stainless steel coupons inoculated with Salmonella were dried and stored at a range of temperatures and relative humidity (RH) levels representing factory conditions. Viability was determined from 1 to 22 days. Survival curves obtained for most isolates and storage conditions displayed exponential inactivation described by a log-linear model. Survival was affected by environmental temperatures and RH with decimal reduction times (DRTs) ranging from <1 day to 18 days. At 25 °C/15% RH, all isolates survived at levels of 103 to 105 cfu for >22 days. Furthermore, temperatures and RH independently influenced survival on stainless steel; increasing temperatures between 10 °C and 37 °C and increasing RH levels from 30–70% both decreased the DRT values. Survival curves displaying a shoulder followed by exponential death were obtained for three isolates at 10 °C/70% RH. Inactivation kinetics for these were described by modified Weibull models, suggesting that cumulative injury occurs before cellular inactivation. This study highlights the need to control temperature and RH to limit microbial persistence in the food manufacturing environment, particularly during the factory shut-down period for cleaning when higher temperature/humidity levels could be introduced.

An Internet of Things Approach for Water Efficiency: A Case Study of the Beverage Factory

There is a lack of knowledge among food manufacturers about adopting the Internet of Things (IoT)-based water monitoring system and its ability to support water minimisation activities. It is therefore necessary to investigate the applicability of IoT-based real-time water monitoring systems in a real food manufacturing environment to pursue water-saving opportunities accordingly. This article aims to propose an architecture of an IoT-based water-monitoring system needed for real-time monitoring of water usage, and address any water inefficiencies within food manufacturing. This article looks at a study conducted in a food beverage factory where an IoT-based real-time water monitoring system is implemented to analyse the complete water usage in order to devise solutions and address water overconsumption/wastage during the manufacturing process. The successful implementation of an IoT-based real-time water monitoring system offered the beverage factory a detailed analysis of the water consumption and insights into the water hotspots that needed attention. This action initiated several water-saving project opportunities, which contributed to the improvement of water sustainability and led to an 11% reduction in the beverage factory’s daily water usage.

Exploring Listeria monocytogenes perceptions in small and medium sized food manufacturers: Technical leaders' perceptions of risk, control and responsibility

Due to its ability to colonize, grow and form in niches in food manufacturing environments, the management of Listeria monocytogenes can be complex, particularly for food manufacturing small and medium sized enterprises (SMEs). In addition to an effective food safety management system, the perceptions of risk, control and responsibility within a food manufacturing business are important influential factors associated with the management of L. monocytogenes. Research exploring managerial perspectives of L. monocytogenes in food manufacturer SMEs is lacking. Consequently, this study conducted in-depth interviews (n = 10) with technical leaders from food manufacturing SMEs to ascertain factors that may influence listeria management, such as factors associated with cultural dimensions. Perceived risks associated with L. monocytogenes were related to business reputation and consumer health impacts, but such events were perceived to be unlikely. Technical leaders reported having clearly defined and well executed processes to ensure food safety; but for some, L. monocytogenes, as a single pathogen was seldom considered. Despite acknowledging that “everyone” had responsibility for ensuring control of the pathogen, technical leaders indicated that the ‘people’ attributes associated with organisational culture were difficult factors to control and manage. Trust in staff ability to assure food safety was widely discussed, with technical leaders acknowledging that food handlers may not necessarily have specific knowledge regarding L. monocytogenes. Some technical leaders perceived themselves as having the greatest levels of responsibility for L. monocytogenes. Overall, technical leaders perceived a medium level of risk, with high levels of control and high levels of responsibility for L. monocytogenes. Optimistic bias, illusion of invulnerability, illusion of control, and perceived attribution of responsibility are discussed, which may hinder implementation of effective listeria management in SME food manufacturing businesses. Consideration of specific pathogen risks in food manufacture in relation to food safety cultural dimensions may assist development of highly targeted and effective interventions.

Genomic Markers for Quaternary Ammonium Compound Resistance as a Persistence Indicator for Listeria monocytogenes Contamination in Food Manufacturing Environments

Persistent contamination of food manufacturing environments by Listeria monocytogenes is an important public health risk, because such contamination events defy standard sanitization protocols, for example, the application of quaternary ammonium compounds such as benzalkonium chloride (BC), providing a source for prolonged dissemination of the bacteria in food products. We performed whole genome sequencing analyses of 1,279 well-characterized L. monocytogenes isolates from various foods and food manufacturing environments and identified the bcrABC gene cassette associated with BC resistance in 531 (41.5%) isolates. The bcrABC cassette was significantly associated with L. monocytogenes isolates belonging to clonal complex (CC) 321, CC155, CC204, and CC199, which are among the 10 most prevalent genotypes recovered from foods and food production environments. All but 1 of the 177 CC321 isolates harbored the bcrABC cassette. In addition, 384 (38.6%) of the 994 isolates recovered from foods representing 67 different CCs and 119 (59.2%) of isolates from food manufacturing environmental samples representing 26 different CCs were found to harbor the intact bcrABC cassette. A representative set of 69 isolates with and without bcrABC was assayed for the ability to grow in the presence of BC, and 34 of 35 isolates harboring the bcrABC cassette exhibited MICs of ≥10 μg/mL BC. Determination of bcrABC in isolates could be achieved using both PCR and whole genome sequencing techniques, providing food testing laboratories with options for the characterization of isolates. The ability to determine markers of quaternary ammonium compound resistance such as bcrABC and epidemiologic lineage may provide risk managers with a tool to assess the potential for persistent contamination of the food manufacturing environment and the need for more targeted surveillance to ensure the efficacy of mitigation actions.

Technological and microbiological characteristics of indigenous food produced in Gabon.

The purpose of this study was to provide contextual information on indigenous food's technologies and safety from Gabon. The strategic focus being to promote local food with enhanced nutritional value and improved safety. An investigation and monitoring were carried out to elucidate their process flow diagrams and to identify safety failures. Samples were taken for microbiological analysis using conventional culture-based techniques. Detection and identification of Salmonella in samples were confirmed using PCR based method by targeting invasion plasmid antigen B (IpaB) gene. The investigation shows that women play a protagonist role in the technical know-how of Gabonese indigenous foods in a context that is evolving towards the disappearance of this knowledge. The food production process remains archaic, which makes the environment impact on food safety. Indeed, the proximity of food manufacturing environment to animals, waste, or latrines coupled with the lack of hygiene and manufacturing practices affect the quality of these foods. This is reflected in our study's microbiological results, namely, Aerobic Mesophilic Bacteria ranged from 3.53 to 11.96 log CFU/g and indicators of fecal contaminations of up to 8.21 log CFU/g. Salmonella is detected in 18.69% of samples. The presence of these bacteria is a risk for consumer health. Although some of these foods can be considered as a fermented food, the producers should be further educated and encouraged to take preventive measures to ensure the quality of these food products. A much more subtle approach based on microbial ecology of these foods should be explored for better exploitation.

A case study of food handler hand hygiene compliance in high-care and high-risk food manufacturing environments using covert-observation

ABSTRACT Observation of behaviour is superior to cognitive data, which does not equate to behaviour. Covert-observation is seldom used in food manufacturing to assess behaviour. In this case study, closed-circuit-television footage (15 h) in a business were reviewed to assess hand hygiene compliance using an electronic-checklist. Hand hygiene attempts were observed prior to entering high-risk (cake/pie)(n= 47) and high-care (sandwich/salad)(n= 153) production areas. Business hand hygiene protocol required handwashing durations ≥ 20 s. Observed durations ranged 1–71 s, <96% of attempts were <20 s. Significantly longer durations were observed when food handlers were in the presence of others (12 s) than when alone (9 s). Although <99% utilised soap, only 56–69% wetted hands first. Failure to rub all parts of hands was commonplace (<87%) and 24–35% failed to apply sanitiser after drying. Consequently, >98% of observed attempts before entering production areas did not comply with the protocol. Observed non-compliant practices may have implications for food safety in manufacturing.

Sensors support machine learning

Sensors support machine learning

Pet Food Factory Isolates of Salmonella Serotypes Do Not Demonstrate Enhanced Biofilm Formation Compared to Serotype-Matched Clinical and Veterinary Isolates.

Environmentally persistent Salmonella in the pet food factory environment has been described, with biofilm formation suggested as a candidate mechanism contributing to their persistence. In this study the ability of a panel of Salmonella isolates from factory, clinical, and veterinary sources was investigated for their ability to form biofilms at 24 and 48 hours. The effect of nutrient availability and incubation time on biofilm formation was investigated using full strength and diluted 1/20 TSB media at 37°C, 25°C, 15°C, and 10°C. Results highlighted that all the Salmonella isolates were able to form biofilms in both nutrient conditions and this was highly correlated with temperature. At 25°C, biofilm formation was enhanced in diluted 1/20 TSB and increased incubation time (48h) (p= <0.001). However, this was not observed at 10°C, 15°C, or 37°C. None of the factory isolates demonstrated enhanced biofilm formation in comparison to serotype-matched isolates from veterinary and clinical sources. Salmonella enterica Senftenberg 775W was the strongest biofilm former at 15°C, 25°C, and 37°C in all the conditions tested (p=<0.05). Biofilm formation is an important mechanism of environmental persistence in the food manufacturing environment; however, there is no evidence of an enhanced biofilm-producing phenotype in factory persistent strains.

Low-concentration Sorbic Acid Promotes the Induction of Escherichia coli into a Viable but Nonculturable State.

The effect of food preservatives and sanitizers at low concentrations on the induction of Escherichia coli into a viable but nonculturable (VBNC) state was investigated. When E. coli was incubated in physiological saline at 37℃, the viable cell count measured by plate counting was approximately 3-logs lower than that measured by flow cytometry after 30 days. This difference, and morphological changes in cells, confirmed the transition of E. coli into a VBNC state. Adding 10 μg/l of sorbic acid significantly promoted the induction of E. coli into a VBNC state. This effect was not seen with benzoic acid or sodium hypochlorite at the same concentration. Resuscitation of E. coli VBNC cells was successful when they were grown in nutrient broth containing sodium pyruvate. These results suggest that the presence of low concentrations of food additives in a food manufacturing environment may act as potential triggers for bacterial VBNC induction.

The Influence of Organizational Subcultures on Food Safety Management

This study considers the influence of food subcultures within the food manufacturing environment and the adoption of food safety management practices. The influence of diversity within the overarching food safety culture of a food manufacturing operation is discussed through the use of case studies. Following a review of the literature, four subcultures were proposed (i.e., executive, operations, engineering, and technical / quality) each with its own unique identity and modus operandi. Understanding the interaction of these subcultures within the visible and invisible elements of food safety culture is critical to prevent a food safety incident and associated recall.