Understanding the microbial community of cheese is important in the dairy industry, as the microbiota contributes to the safety, quality, and physicochemical and sensory properties of cheese. In this study, the microbial compositions of different cheeses (Cheddar, provolone, and Swiss cheese) and cheese locations (core, rind, and mixed) collected from the Arbuthnot Dairy Center at Oregon State University were analyzed using 16S rRNA gene amplicon sequencing with the Illumina MiSeq platform (Illumina, San Diego, CA). A total of 225 operational taxonomic units were identified from the 4,675,187 sequencing reads generated. Streptococcus was observed to be the most abundant organism in provolone (72 to 85%) and Swiss (60 to 67%), whereas Lactococcus spp. were found to dominate Cheddar cheese (27 to 76%). Species richness varied significantly by cheese. According to alpha diversity analysis, porter-soaked Cheddar cheese exhibited the highest microbial richness, whereas smoked provolone cheese showed the lowest. Rind regions of each cheese changed color through smoking and soaking for the beverage process. In addition, the microbial diversity of the rind region was higher than the core region because smoking and soaking processes directly contacted the rind region of each cheese. The microbial communities of the samples clustered by cheese, indicated that, within a given type of cheese, microbial compositions were very similar. Moreover, 34 operational taxonomic units were identified as biomarkers for different types of cheese through the linear discriminant analysis effect size method. Last, both carbohydrate and AA metabolites comprised more than 40% of the total functional annotated genes from 9 varieties of cheese samples. This study provides insight into the microbial composition of different types of cheese, as well as various locations within a cheese, which is applicable to its safety and sensory quality.

The objective of this study was to evaluate the rate of Maillard browning in 3 commercial sweet whey powders (WC1, WC2, and MW1), under accelerated shelf-life testing (ASLT) and under normal storage conditions (21 degrees C and 35% RH). Rate of brown pigment formation (k) obtained from short-term ASLT of whey powder was compared with actual findings obtained from the long-term shelf-life testing under normal conditions. Deterioration by Maillard browning, measured by spectrophotometer, was compared with changes in color (Hunter Laboratory), free moisture, titratable acidity, and sensory attributes. Results suggest that estimated k (from ASLT) was comparable with the observed rate (obtained at ambient temperature) for 2 producers (WC1, MW1). The actual k values observed for samples WC1, WC2, and MW1, stored under normal conditions, were 0.0031, 0.0080, and 0.0148 color units/g of solid per mo, respectively. The estimated values of k for samples WC1, WC2, and MW1 were 1.12, 4.90, and 1.35 times more than the observed values, respectively. The Q10 values (increase in reaction rate for a 10 degrees C temperature increase) ranged from 1.77 to 4.14, and the activation energies ranged from 15.9 to 28.4 kcal/mol. Hunter Laboratory values L* and a* appeared most sensitive to changes during storage. Free moisture content, and acidity increased significantly with storage. However, no significant changes were detected by the sensory panel in the attributes considered.

Whey disposal can be both an environmental and economic challenge for artisanal creameries. Lactose in whey can be fermented to produce ethanol and subsequently distilled. The objective of this study was to use a process-based life cycle analysis to compare carbon dioxide-equivalent (CO2e) emissions and water usage associated with the artisanal or craft production of clear, unaged spirits using whey or malted barley as fermentation substrate. Differences in production were assessed based on key process differences: energy used, water used, distillation by-product disposal, and mass of CO2 produced during fermentation. For this study, whey was assumed removed from the artisanal creamery waste stream. Quantifiable differences were evaluated per 750-mL (45% alcohol by volume) functional unit and expressed as mass-equivalent CO2 emissions (kg of CO2e) and mass of water (kg) used. The CO2e emissions and water usage were quantified using published data, thermodynamic calculations, and mass-balance calculations for a hypothetical distillation system. The process-based life cycle analysis estimated that distillation of fermented whey reduced overall CO2e emissions by 8.4 kg per functional unit and required 0.44 kg less water added into the production process compared with production of a similar clear, unaged spirit using malted barley as substrate. Our preliminary analysis suggests that conversion to distilled whey spirit is a more environmentally responsible approach compared with landfill disposal of whey.

The concept of local food is rapidly gaining importance within the United States. The foundation of local food is terroir, which links a food to its production environment. The purpose of this study was to investigate evidence of terroir in milk sourcing and its influence on Cheddar cheese flavor. Specifically, the study was designed to assess if consumers could differentiate between Cheddar cheeses made with milk from different dairy farms. Milk from 5 locations, including single dairy farms and commingled sites, was collected from around the state of Oregon. Using raw and pasteurized counterparts of the milk, Cheddar cheese was made and aged. At 5 and 9mo into aging, Cheddar cheese consumers were asked to group the samples based on perceived similarity/dissimilarity of cheese flavor. Grouping data were subjected to multidimensional scaling and subsequent cluster analysis. Results at 5mo into aging revealed that cheeses made by milk originating from different farms (80km apart) within the same region were perceived as different, whereas cheeses made with milk from neighboring farms (5km apart) were grouped together, irrespective of heat treatment (i.e., raw vs. pasteurized). Cheeses made with commingled milk from different regions grouped together. At 9mo of aging, in contrast, a clear separation of perceived flavor was present between the pasteurized and raw cheese samples, whereas the effect of milk sourcing was less pronounced. These data suggest that the geographical location of the milk source has an effect on the flavor of Cheddar cheese, but that the practices of milk commingling and heat treatment likely reduce the effect of geographical location, particularly as cheese ages.