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Environmental monitoring programs to assess food safety risks from food contact surfaces in Washington state apple packinghouses
Full text linkWashington State is the leading producer of apples in the United States. The increasing association of foodborne outbreaks and recalls of fresh apples caused by cross-contamination with the pathogen Listeria monocytogenes within packing facilities, coupled with new regulations from the Food Safety Modernization Act (FSMA), have emphasized the focus on food safety interventions within the apple packing industry. As a result, implementing a robust environmental monitoring program (EMP) is warranted to mitigate the risk of potential contamination with foodborne pathogens. Five apple packinghouses located in Washington State were sampled for the quantification of populations of indicator organisms such as aerobic plate count, Enterobacteriaceae, coliforms and Escherichia Coli, the detection of Listeria species (spp.), and rapid tests such as ATP swabs and glucose and lactose residue swabs on food contact surfaces (FCS). Given that apples are stored up to 12 months in cold storage rooms, packinghouses were visited quarterly to obtain data representing different storage time points. Rapid tests were assessed to evaluate their accuracy in predicting microbial loads on packing surfaces after sanitation procedures over the 2018 packing season. Rapid tests were neither suitable to assess microbial populations nor to detect Listeria spp. Moreover, populations of indicator organisms were not related to the detection of Listeria spp. To assess the prevalence of Listeria spp., 2,988 sample sites were tested after sanitation and after three hours of packinghouse operations over the 2018 and 2019 packing seasons. Among all tested samples, 4.6% were positive for Listeria spp. The wax coating unit operation was associated with the highest frequency of detection of Listeria spp. Several niche points for Listeria spp. were identified, including polishing brushes, brushes and dividers under fan/air blowers, and dryer rollers. An increase in the prevalence of Listeria spp. was observed throughout crop storage time. The results of this research provide a better understanding of the use of rapid tests and indicator organisms testing for the implementation of effective EMP's. Correspondingly, based on the most Listeria-prevalent FCS, strategies to mitigate the risk of contamination with L. monocytogenes can be designed to prevent future outbreaks and recalls
Transcription Analysis of \u3cem\u3eEscherichia coli\u3c/em\u3e O157:H7 Exposed to Sodium Benzoate
Full text linkAdvances in microbial genetics have allowed discovery and assignment of function for many genes. High-throughput transcription analysis can be conducted for foodborne pathogens to give insight into mechanisms of adaptation and survival in adverse conditions. With heightened knowledge of gene expression in these conditions, steps can be taken to counteract adaptive mechanisms and inhibit growth or survival of foodborne pathogens.
Sodium benzoate is a food antimicrobial that is commonly used in beverages and fruit juices. A study was conducted to determine the gene expression of Escherichia coli O157:H7 when exposed to sodium benzoate.
First, a qualitative study to determine transcription of marA, stx1, and eaeA was undertaken using real-time reverse transcriptase polymerase chain reaction (rt-RT-PCR). Expression of the mar operon causes increased antimicrobial resistance in bacterial pathogens. Shiga toxin 1 (Stx1) is a well described verotoxin produced by enterohemorrhagic E. coli (EHEC), and EaeA, or intimin, helps establish E. coli O157:H7 in the intestinal tract. For marA and stx1, rt-RT-PCR products were detected at a 1-log greater dilution in sodium benzoate treated cells, indicating a greater level of transcription in these cells.
Next, a microarray study was conducted to determine transcription of E. coli O157:H7 when exposed to 0.5% sodium benzoate. Results indicate that the phosphate specific transport (Pst) system was rapidly (within 5 min) up-regulated in response to sodium benzoate. This system is essential for supplying phosphate used in synthesizing compounds such as ATP, phospholipids, and proteins. Research with Mycobacterium smegmatis also shows that this system can serve as an efflux pump.
The urease operon was also shown to be up-regulated in E. coli O157:H7 after 60 min of exposure to sodium benzoate. Urease catalyzes the hydrolysis of urea to ammonia and carbon dioxide, and is one mechanism by which microorganisms survive in acidic environments. In this study, exposure of E. coli O157:H7 to sodium benzoate at neutral pH showed increase in transcription of the entire urease operon.
These data indicate that stx1 and marA genes as well as the Pst system and urease operon could play a role in pathogen virulence and survival when treated with sodium benzoate
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ESTABLISHING CRITICAL LIMITS FOR COMMERCIAL ANTIMICROBIALS AGAINST FOODBORNE PATHOGENS IN SIMULATED WATER IMMERSION SYSTEMS
Full text linkThe increasing number of foodborne illness, outbreaks and recalls associated with fruits and vegetables due to cross-contamination has highlighted the need to develop and implement better food safety practices in the produce industry. While cross-contamination can occur during any stage of production, surveillance data from past whole produce outbreaks have repeatedly found contamination within the packing facility. Previous studies have established the risk of cross-contamination in produce recirculating water systems (e.g., dump tanks and flumes) if concentrations of commercial antimicrobials are not properly maintained. However, most Environmental Protection Agency (EPA) labels for commonly used antimicrobials in these systems control for spoilage organisms rather than organisms that are a public health concern, creating challenges when trying to establish concentrations to effectively mitigate and manage food safety risks. Therefore, the goal of this research was to determine the efficacy of two commonly used antimicrobials [sodium hypochlorite (NaOCl) and peroxyacetic acid (PAA)] against Shiga-toxigenic Escherichia coli (STEC), Listeria monocytogenes, and Salmonella enterica in water with similar quality characteristics seen in these types of systems. Water quality parameters were collected throughout production in three different apple packing facilities in Washington State to establish industry-relevant water conditions for in-lab experiments. Organic load was varied to simulate wash water with organic loads of 30, 500 and 2500 ppm of chemical oxygen demand (COD). Target concentrations of NaOCl (10 to 100 ppm) or PAA (25 to 80 ppm) were added to water. Water was portioned into 500 mL samples and inoculated with a five-strain cocktail of STEC, Listeria, or Salmonella. Aliquots were taken over a duration of 60 seconds, neutralized, serially diluted, and enumerated to determine inactivation. Keeping concentration and time constant, increasing organic load resulted in a significant (p<0.05) reduction in microbial inactivation of PAA and NaOCl for all organisms. Overall, efficacy of microbial inactivation was highly dependent on COD level, sanitizer concentration and exposure time for STEC, Listeria, and Salmonella. Free chlorine was most impacted by increasing organic load. This research highlights the need to set antimicrobial limits based upon expected COD in order to manage risk of cross-contamination within these postharvest washing systems
Produce safety rule exemptions and exclusions for Washington produce growers
Full text linkThe Standards for the Growing, Harvesting, Packing and Holding of Produce for Human Consumption, commonly referred to as the Produce Safety Rule, was developed by the U.S. Food and Drug Administration (FDA) to provide food safety standards for fresh produce from the field through packing and holding. This is just one regulation that was developed through passage of the Food Safety Modernization Act and aims to reduce the overall burden of foodborne illness in the United States. The full text of the regulation can be found in the Code of Federal regulations in Title 21, Part 112 (U.S. FDA 2019c; Cornell Law School n.d.). It is important for Washington State food producers to know the new regulation and its requirements, even for farms which may fall under one of the exemptions. This publication covers the two categories that Washington growers may fall into if their farm does not have to comply with the full PSR requirements, these are farms which are excluded from all requirements of the PSR and farms which are exempt from certain requirements of the PSR
SP746-A Developing a Worker Health and Hygiene Program for Fruit and Vegetable Harvesting and Packing Operations
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Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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Characterization of the apple peel microbiota: Bacterial and fungal components under environmental, laboratory, and storage conditions
Full text linkApples are among the most consumed fruit in the United States, but the crop has recently been shown to exhibit some vulnerability to contamination along the supply chain, as evidenced by recent apple-related outbreak and recall events. In contrast to the relatively short duration of harvest and packing activities, apples spend a significant amount of time in the storage environment, up to one year. Many opportunities for contamination exist within this environment that result in significant postharvest losses, with postharvest fungal decay a leading cause. While the initial fungal inoculum is expected to occur in the orchard environment, decay emerges in storage by fungi that necrotize healthy apple tissue. The presence of these necrotic fungal pathogens and the changes induced upon the apple peel environment may support the growth of saprophytic and psychrotrophic foodborne pathogens like Listeria monocytogenes. The 2014 caramel apple outbreak showed the apple’s ability to support the growth of this pathogen under favorable conditions, which usurped the previous thought that apples were a relatively low risk commodity. The environmental shifts that occur on the fresh apple surface across harvest, storage, and production activities affect the microbiome of the apple peel. Given the extended time apples are in storage, the effect that this environment has on the apple surface microbiota has been insufficiently studied. Furthermore, the relationship between postharvest necrotic fungal pathogens and food safety-relevant microorganisms in industry-relevant storage conditions has not been studied in this environment. Additionally, the use of metagenomic methods in fresh produce management has been shown to enhance the industry’s understanding of microbiota of food matrices, but these methods have not been validated for commodities with characteristically low biomass, such as apples. As such, recommendations for enhancing the food safety of fresh apples in these environments is lacking. The evaluation of these relationships using metagenomic methodologies through these experiments has provided insight into the previously poorly studied environment of fresh apple storage and the interactions that occur on the fruit surface and enabled the recommendation of industry practices and interventions to minimize the risks associated with fresh apple production
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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