5 research outputs found

    Predictors of Compliance with the Food Safety and Inspection Service\u27s Listeria Rule, 2012-2015

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    Since 1987, the Food Safety and Inspection Service (FSIS) has implemented a zero-tolerance policy for Listeria monocytogenes (Lm) in ready-to-eat (RTE) meat and poultry products, which culminated with the implementation of the Listeria rule in 2003. While researchers have extensively examined human listeriosis and its causative agent, Lm, there remained a significant gap in the current literature regarding how, singly or in combination, establishment size, RTE product type, Listeria alternative used, and FSIS district of production predict compliance with the Listeria rule. Therefore, the purpose of this quantitative study was to investigate the relationship between establishment size, RTE product type, Listeria alternative used, FSIS district of production, and compliance with the Listeria rule. The deterrence theory was used to explain the relationships and associations between variables. Archival Lm sampling data collected between 2012 and 2015 by FSIS was used to analyze the relationships. Chi-square tests showed no significant statistical relationship between establishment size, Listeria alternative used, FSIS district, and compliance, but they did show a significant association between compliance, RTE salt-cured products, and fully cooked products. Additionally, logistic regression analysis showed that the odds of an Lm-positive sample was higher for salt-cured products than for fully-cooked products. This study\u27s findings indicate the need for a reevaluation of FSIS Listeria prevention policy, with a focus on salt-cured products. These results can influence positive social change if used in a targeted public health outreach/education program that focuses on the food safety risks associated with salt-cured products

    Sample preparation methods and molecular based detection for the rapid isolation and identification of Listeria monocytogenes in food samples

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    Magister Scientiae - MScListeria monocytogenes is a Gram-positive bacterium responsible for listeriosis, a food-borne disease, which may result in severe illness and possible death. The importance of L. monocytogenes as a food-borne pathogen has been recognized since the 1980's when a correlation between the cunsumption of contaminated foodstuffs and human listeriosis outbreaks was observed. Listeriosis occurs with the ingestion of contaminated foods. The aim of this study involved developing DNA based methods to aid the food industry for the fast detection of L. monocytogenes in food products. Therefore assays were developed in such a way that they will have potential applications in the food idustry.South Afric

    The implementation of sub-typing techniques to determine the diversity of L. monocytogenes strains adapted to the food processing environment and their association with human listeriosis cases

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    Philosophiae Doctor - PhDListeria monocytogenes has been established as a food-borne pathogen since the early 1980s and has become a big concern for the food industry and Public Health authorities (Doyle 2001; Oliveira et al. 2003; Capita et al. 2005; Conly and Johnston 2008). It is a Gram-positive, opportunistic facultative intracellular bacterium which is frequently present in nature and may be found in any food environment (Liu 2006; Chen et al. 2007; Conly and Johnston 2008). Of the six species of Listeria, L. monocytogenes is the only one capable of causing listeriosis, a severe food-borne illness in humans (de Vasconcelos et al. 2008). For the average healthy person, although the incidence of infection is low, symptoms of febrile gastroenteritis may be presented (Gianfranceschi et al. 2007; Kersting et al. 2010). In immunocompromised individuals however, the hospitalization and mortality rates are amongst the highest for pathogenic organisms (Tran and Kathariou 2002; Lin et al. 2006; Schuppler and Loessner 2010). Illnesses such as septicaemia and central nervous system infections may also occur in these individuals (Roberts et al. 2006; Schuppler and Loessner 2010). Pregnant women and their fetus are also largely at risk where pre-term delivery and birth defects may occur as a result of listeriosis (Doyle 2001; Garrido et al. 2008). The epidemiological surveillance systems for the reporting of listeriosis are poor as it is a non-notifiable disease in many countries. Therefore, the incidence of infection that is regarded as low must be reconsidered (Mammina et al. 2009; Pinto et al. 2010). Listeria monocytogenes can reproduce in a wide variety of reservoirs within food processing plants, thereby contaminating the food which then poses a risk for food-borne illness. It can be transmitted from infected animals to humans and also through the consumption of foods from animal origin (Kalender 2003; Kersting et al. 2010). Animals are infected by Listeria spp. found in the environment; the organism is then transmitted through the blood, milk and excrement of the animal back into the environment where manure, soil, feed and water can become contaminated again (Akpolat et al. 2004; Kersting et al. 2010). Poultry products and ready-to-eat (RTE) food that support the growth of L. monocytogenes, including soft cheeses, unpasteurized milk, hotdogs, deli meats, vegetables and fruits have been linked to cases of listeriosis (Rørvik et al. 2003; Chen et al. 2007; Conly and Johnston 2008; Ford 2010; Kersting et al. 2010). Regardless of HACCP systems that are in place in the food processing plants, listeriosis outbreaks still occur as a result of the ingestion of these food products. Serotyping, based on the serological reaction between somatic (O) and flagellar (H) antigens and their corresponding sera, has identified 13 L. monocytogenes serotypes (Nadon et al. 2001; Wiedmann 2002; Kérouanton et al. 2010). Of the 13 serotypes of L. monocytogenes, 1/2a, 1/2b and 4b are responsible for more than 95% of listeriosis infections in humans (Mereghetti et al. 2002; Moorhead et al. 2003; Borucki et al. 2004;de Vasconcelos et al. 2008). L. monocytogenes serotypes 1/2a and 1/2b are mainly associated and isolated sporadically from food and 4b is responsible for the major human epidemic cases (Gilbreth et al. 2005). L. monocytogenes serotypes 1/2a and 1/2b are also responsible for sporadic cases of human illness (Wiedmann 2002).South Afric

    Feeding the Pharaohs: A Discussion and Object Study of Fowl Victual Mummies from Ancient Egypt

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    Food offerings were a critical part of ancient Egyptian funerary ritual, as these offerings sustained the dead in the afterlife. Among food offerings placed in tombs were victual mummies: cuts of meat or fowl mummified and wrapped in linen bandages like their human counterparts. This thesis seeks to define fowl victual mummies as an object class through a discussion of their procurement, processing, and production. It addresses the status of victual mummy categorization. This thesis considers the following prompts: are fowl mummies truly mummy in their preparation and presentation? Are fowl victual mummies prepared specifically as food items, ready for long-term consumptions and storage? Or can fowl victual mummies represent a unique hybridization of these trades? X-ray imaging and pXRF analysis were conducted on fowl victual mummy 1981.1.18 at the Art Museum of the University of Memphis, coinciding with an analysis of published victual mummies, to address these questions

    Risk assessment for Listeria monocytogenes in traditionally processed fish from informal markets in Accra and Tema

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    Traditionally processed fish contributes significantly to food and nutrition security in Ghana. The processing and handling has however been associated with unsanitary and unhygienic practices with documented occurrence of food-borne pathogens. The products are also mainly sold on informal markets, where earlier studies reported the occurrence of Listeria monocytogenes in products sold therein. This study sought to determine the occurrence of L. monocytogenes in traditionally processed (smoked, dried, salted) fish sold on informal markets and to assess the exposure of consumers to the pathogen and the associated risk of illness. The study was based on the Codex Alimentarius protocol for microbial risk assessment. Surveys were conducted on selected traditional processors and consumers to determine processing practices and consumption patterns (frequency and portion sizes) respectively. Samples of traditionally processed fish were procured from some processors and consumer markets in the survey locations for microbial analysis to determine the occurrence and concentrations of L. monocytogenes in the processed fish. Microbial challenge tests were also done by cooking deliberately-contaminated fish for short and long time intervals to determine the survival of the pathogen during domestic cooking. Data from the survey (quantities of fish often consumed) and the laboratory analyses (microbial load) were used to assess the exposure of consumers to the pathogen, and also fitted to parametric (probability) functions to characterize the dose response using Monte Carlo simulations with the @Risk software (version 5.5, Palisade Corporation). Prevalence of L. monocytogenes in the fish products sampled from the markets was high (40-80%). However, the pathogen was not detected in smoked fish sampled immediately after processing, suggesting that post-processing contamination occurred. The concentrations of the pathogen in the products were generally low (102-3 CFU/g), and decreased from smoked fish through to sundried fish. The pathogen also survived in fish used for the challenge test. The estimated risks of illness were low, ranging from 1 in 100 to 1 in 100,000,000,000 chances of illness. Higher risks of illness were recorded for consumption of smoked fish than for sundried fish and salted fish, in that order. Consumers with high susceptibility to L. monocytogenes infection (elderly, children and pregnant women) were at a greater risk of illness than low risk individuals (non-pregnant adults aged 18 – 39 years). The findings suggest that consumers are exposed to ingesting L. monocytogenes through consumption of traditionally processed fish on informal markets. However the risk of illness is low. Improvements in hygienic processing and post-processing handling of fish as well as proper cooking of the fish products before consumption are recommended
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