Gram-negative postpasteurization contamination patterns of single-serve fluid milk produced in 4 different processing facilities

ABSTRACT: An analysis of historic data on high temperature, short time (HTST) fluid milk quality showed higher total bacterial counts and lower sensory defect judging scores at d 14 postprocessing for milk packaged in single-serve containers as compared with milk packaged in half-gallon containers from the same processing facilities. As postpasteurization contamination with gram-negative bacteria is likely a major contributor to an increased spoilage risk associated with milk packaged in single-serve containers, we performed a comprehensive assessment of the microbial quality and shelf life of 265 commingled single-serve HTST fluid milk samples (including white [unflavored] skim, white [unflavored] 1%, chocolate skim, and chocolate 1%) collected over 2 visits to 4 commercial fluid milk processing facilities. Over 2 initial sampling visits, the frequency of gram-negative spoilage ranged from 14 to 79% of the product collected from the 4 facilities, with significant differences of gram-negative spoilage frequency between sampling visits, facilities (sampling visit 1, sampling visit 2, and both sampling visits combined), milk types (sampling visit 2), and filler lanes (sampling visit 2). We found no significant differences in the frequency of gram-negative spoilage between sampling time points (e.g., beginning, middle, and end of production run). Across facilities, single-serve containers of milk with gram-negative contamination showed significantly higher bacterial counts on d 7 and 14 and significantly lower sensory scores as compared with those without gram-negative contamination. Follow-up investigations, based on in-facility surveys that identified carton forming mandrels as filler components that frequently failed quality assurance ATP swab checks, found that bacterial genera, including Pseudomonas and Bacillus, isolated from single-serve milk samples were also frequently isolated from mandrels. Although interventions aimed at improving cleaning and sanitation of mandrels did not lead to significant reduction of gram-negative spoilage frequency in a comparison of 398 control and 400 intervention samples, our data still suggest that the unhygienic design of single-serve fillers is likely a root cause of gram-negative contamination of single-serve milk

Sensory Evaluation of Common Ice Plant (Mesembryanthemum crystallinum L.) in Response to Sodium Chloride Concentration in Hydroponic Nutrient Solution

Common ice plant (Mesembryanthemum crystallinum L.) is a novel edible plant with a succulent and savory flavor. The plants display prominent epidermal bladder cells (EBCs) on the surface of the leaves that store water and sodium chloride (NaCl). The plants have high nutritional value and are adapted to saline soils. Previous research has determined the impact of NaCl on the growth and mineral content of ice plant, but as NaCl has an impact on a food’s sensory properties, an interesting question is whether saline growth media can affect the plant’s taste and texture, and if this alters consumers’ sensory response to ice plant. The objective of this study was to evaluate the sensory aspects of ice plant, as well as consumer liking in response to increasing NaCl concentration in hydroponic nutrient solution. Four-week-old seedlings of ice plant were transplanted into deep water culture (DWC) hydroponic systems and treated with five NaCl concentrations (0 M [control], 0.05 M, 0.10 M, 0.20 M, and 0.40 M NaCl). Eight-week-old plants (after four weeks of NaCl treatment) were harvested, and the middle leaves of each plant were sampled for consumer testing. A total of 115 participants evaluated various flavor, texture, and appearance aspects of ice plant and provided their liking ratings. The consumers were able to discriminate differences in salt intensity from the plants based on NaCl treatment in the hydroponic nutrient solution. Low NaCl concentrations (0.05–0.10 M) did not have obvious adverse effect on consumer liking, which aligns with the result of previous research that 0.05–0.10 M NaCl could largely stimulate the growth of ice plant. NaCl concentrations higher than 0.20 M are not recommended from both a production and consumer perspective. With increased NaCl level in plant samples, the consumers detected more saltiness, sourness, and fishiness, less green flavor, and similar levels of bitterness and sweetness. NaCl treatment had no effects on leaf appearance and texture, and the consumers’ overall liking was mainly determined by flavor. Overall, ice plant presents some unique attributes (salty and juicy) compared to other edible salad greens; however, consumer awareness of ice plant is very low, and purchase intent is relatively low as well. Consumers picture ice plant being used mainly in salads and in restaurants

Impact of sustainability and nutritional messaging on Italian consumers' purchase intent of cereal bars made with brewery spent grains

This work focuses on the reuse of brewery spent grains (BSGs), the most abundant by-product of the beer industry, today mainly used as animal feed. BSGs are rich in fibers and proteins as well as phenolic compounds, all of which are beneficial for human nutrition. Cereal bars containing 12% BSG were formulated and characterized instrumentally. Moreover, 159 panelists representative of young Italian consumers evaluated the bars in a central location test, along with a commercial cereal bar. Products were first evaluated blind, and then in an informed condition where additional product-specific nutritional and sustainability information was revealed, thus the purchase intent was determined. While the control product outperformed the BSG bar in most of the hedonic and sensory measures, the BSG sample was perceived as "natural/made with natural ingredients" by a significantly higher number of panelists (49%) compared to the control (30%). Additionally, even in the lower performing formulation, a significant positive effect on purchase intent was observed when providing either nutrition (fiber content) or sustainability (use of upcycled ingredients) information. The acceptable price range for the BSG and the commercial bar was very similar, whereas the optimal pricing point for the BSG was lower than the control. For the BSG product, sustainability information had significantly higher impact on purchase intent than nutrition-based information. Results highlight the importance of understanding consumer attitudes toward upcycling and the use of byproducts as ingredients in new food formulations. PRACTICAL APPLICATION: Results show how providing information on product nutrition and sustainability can increase purchase intent in the context of a cereal bar containing upcycled ingredients. The findings of this study can help food and consumer researchers to develop acceptable products that include BSG as an ingredient, potentially replacing other cereals in the recipe. The use of this brewery by-product could add value to the beer supply chain and to the final product as well, being also aligned with the current market trend of sustainability and functional health benefits

Characterization of the Fermentation and Sensory Profiles of Novel Yeast-Fermented Acid Whey Beverages

Acid whey is a by-product generated in large quantities during dairy processing, and is characterized by its low pH and high chemical oxygen demand. Due to a lack of reliable disposal pathways, acid whey currently presents a major sustainability challenge to the dairy industry. The study presented in this paper proposes a solution to this issue by transforming yogurt acid whey (YAW) into potentially palatable and marketable beverages through yeast fermentation. In this study, five prototypes were developed and fermented by Kluyveromyces marxianus, Brettanomyces bruxellensis, Brettanomyces claussenii, Saccharomyces cerevisiae (strain: Hornindal kveik), and IOC Be Fruits (IOCBF) S. cerevisiae, respectively. Their fermentation profiles were characterized by changes in density, pH, cell count, and concentrations of ethanol and organic acids. The prototypes were also evaluated on 26 sensory attributes, which were generated through a training session with 14 participants. While S. cerevisiae (IOCBF) underwent the fastest fermentation (8 days) and B. claussenii the slowest (21 days), K. marxianus and S. cerevisiae (Hornindal kveik) showed similar fermentation rates, finishing on day 20. The change in pH of the fermentate was similar for all five strains (from around 4.45 to between 4.25 and 4.31). Cell counts remained stable throughout the fermentation for all five strains (at around 6 log colony-forming units (CFU)/mL) except in the case of S. cerevisiae (Hornindal kveik), which ultimately decreased by 1.63 log CFU/mL. B. bruxellensis was the only strain unable to utilize all of the sugars in the substrate, with residual galactose remaining after fermentation. While both S. cerevisiae (IOCBF)- and B. claussenii-fermented samples were characterized by a fruity apple aroma, the former also had an aroma characteristic of lactic acid, dairy products, bakeries and yeast. A chemical odor characteristic of petroleum, gasoline or solvents, was perceived in samples fermented by B. bruxellensis and K. marxianus. An aroma of poorly aged or rancid cheese or milk also resulted from B. bruxellensis fermentation. In terms of appearance and mouthfeel, the S. cerevisiae (IOCBF)-fermented sample was rated the cloudiest, with the heaviest body. This study provides a toolkit for product development in a potential dairy-based category of fermented alcoholic beverages, which can increase revenue for the dairy industry by upcycling the common waste product YAW