This thesis examined the efficacy of various sampling and detection methods used for environmental monitoring of Listeria species on wooden surfaces used for cheese aging. Government agencies including the Food and Drug Administration (FDA) and United States Department of Agriculture (USDA) recommend enrichment methods coupled with use of environmental sponges and swabs. Our study compared efficacy of sponge swabs manufactured by 3M™ and World Bioproducts. There is a lack of research validating the best performing swab type and enrichment method combination that is sensitive when used on rough, porous surfaces. The sensitivity of these environmental sampling tools and methods are critical considerations to effectively monitor the presence of Listeria species on wooden boards used during aging of artisan cheese. Seasoned spruce wooden shelves, cut into 100cm2 replicates, were spot inoculated with varying concentrations of Listeria species inocula, the Listeria species strains consisted of two L. monocytogenes strains and a Green Florescence Protein (GFP) expressing strain of L. innocua. The inoculated wooden surface was swabbed with three environmental sampling sponge/swab formats (World Bioproducts© EZ ReachTM environmental swabs (WBEZ) with HiCap (WBHC) and Dey-Engley (WBDE) neutralizing broths; and 3MTM environmental swabs (3MTM) with Dey-Engley neutralizing broth). Enumeration methods were used to determine the low target limits of detection. Once the low target concentrations were identified, five enrichment methods consisting of 3MTM Listeria Environmental Plate, FDA, Dual Enrichment, modified USDA, and modified FDA were challenged against low concentrations of Listeria species inocula (0.01 cfu/cm2, 0.1 cfu/cm2, 1 cfu/cm2) and the three environmental sponge swab formats. Performance of the swab formats was assessed by collection of naturally contaminated environmental samples (n=405) from dairy farm environments, swabbing where wooden surfaces existed, and analyzed using the most effective enrichment methods found from previous experiments. Lastly, the wooden surfaces and sponge swabs were observed under a Florescent Microscope using GFP L. innocua to visually determine how each sponge material of the 3M™ and World Bioproducts recovered the inocula. When wood surfaces were inoculated at high concentration levels of Listeria spp., all swab formats performed equally for detecting Listeria. Success of positive recovery at low concentrations was variable, where enrichment methods and swabs were not dependent on each other. The swab format that worked best for detecting low levels of Listeria species was the WBDE sponge swab. The WBDE swab also performed the best in dairy farm environmental sampling. The m-USDA enrichment method was found to be most effective in recovery and repair of low and potentially injured Listeria spp. Wooden surfaces are rough and porous and should be taken into consideration when creating an environmental sampling plan for these food contact surfaces. All swabs and methods performed with only slight variation, but the variation could be significant when monitoring wooden shelves with low level contamination of Listeria species. Artisan cheesemakers who use wooden shelves during the aging of their cheese, should ensure use of the most sensitive detection methods.

Vermont is widely-regarded as a hub for artisan cheese production, with more cheesemakers per capita than any other US state. Despite significant local and statewide support, out-of-state markets are essential to the long-term success of these small-scale producers. In spatially extended supply chains, retailers occupy a pivotal position. This thesis aims to examine the intermediary role of retailers in building social networks between producers and consumers. Consumers appreciate Vermont artisan cheese, in part, because it is embedded in a complex network of social values and relations related to where and how it is produced. Guided by social theories of consumption, sensory experience, and exchange, a transdisciplinary, mixed-methods study was conducted in order to better understand cheese retailers' role in this network. First, participant observation and ethnographic interviews at a specialty cheese shop demonstrated how highly specialized cheese retail professionals (known as a cheesemongers) communicate social information about Vermont artisan cheese to consumers in practice. Specialized narratives are transmitted to consumers through in-store signage and social interactions. These stories also involve the cheesemonger as traveler, developing specialized knowledge of Vermont artisan cheese by traveling to the place of production. A second site of participant observation at a national conference for artisan cheese professionals added breadth to the study. While cheesemongers appear to agree that a certain level of intrinsic quality is necessary for consumer acceptance and preference, many also see the importance of, and derive pleasure from, knowing and conveying the social story, and perceive this to be an important part of their professional role and identity. Second, social network analysis provided a broader examination of relationships between Vermont artisan cheesemakers and retailers in the region. In order to collect data on these relationships, an online survey was distributed to Vermont artisan cheesemakers and follow-up phone calls were conducted. A combination of statistical and network analyses was used to visualize the social structure of the network, identify key actors, and examine qualities of the relationships. The findings suggest that the social network for Vermont artisan cheese is a multiplex system, in which a cheesemaker's relative position in the network is the result of a complex balance--and sometimes compromise--between a cheesemaker's needs, goals, and desires and their various retailers' needs, goals, and desires. Moreover, geographic proximity, time, experience, convenience, cost, history, loyalty, and regard all appear to be important factors in the type of relationship cheesemakers have with retailers, and whether a relationship is established at all.