Browsing by Author "Wiersema, Brian D."

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    Cyberbiosecurity Importance in Relation to Small Fermentation Businesses and How to Integrate it into Known Hazard Planning Tools
    Knapp, Jordan; Strawn, Laura K.; Wiersema, Brian D.; Eifert, Joseph D.; Hamilton, Alexis M. (Virginia Tech, 2024-08-07)
    Cyberbiosecurity threats are on the rise in many various industries (Drape et al., 2021). With attacks on water treatment plants, medical facilities and more, awareness for what cyberbiosecurity is, what it looks like, and how to implement countermeasures into known hazard planning tools is dire. This project set out to address these issues in the context of small fermentation businesses. A survey was conducted but, due to low response rate, there was no statistical nor quantitative analysis performed on the survey results. The information gleaned from the survey was used to better guide how a factsheet would be created and used to gauge, what the fermentation community in North Carolina and Virginia was aware of in relation to food safety, the Food Safety and Modernization Act, and cyberbiosecurity. A factsheet was designed to guide small fermentation businesses on how to identify cyberbiosecurity is, what hazards exist, how to implement control measures into known hazard planning tools, and what methods exist to better protect their businesses.
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    Development and Characterization of a Pilot-Scale Model Cocoa Fermentation System Suitable for Studying the Impact of Fermentation on Putative Bioactive Compounds and Bioactivity of Cocoa
    Racine, Kathryn C.; Lee, Andrew H.; Wiersema, Brian D.; Huang, Haibo; Lambert, Joshua D.; Stewart, Amanda C.; Neilson, Andrew P. (MDPI, 2019-03-19)
    Cocoa is a concentrated source of dietary flavanols—putative bioactive compounds associated with health benefits. It is known that fermentation and roasting reduce levels of native flavonoids in cocoa, and it is generally thought that this loss translates to reduced bioactivity. However, the mechanisms of these losses are poorly understood, and little data exist to support this paradigm that flavonoid loss results in reduced health benefits. To further facilitate large-scale studies of the impact of fermentation on cocoa flavanols, a controlled laboratory fermentation model system was increased in scale to a large (pilot) scale system. Raw cocoa beans (15 kg) were fermented in 16 L of a simulated pulp media in duplicate for 168 h. The temperature of the fermentation was increased from 25–55 °C at a rate of 5 °C/24 h. As expected, total polyphenols and flavanol levels decreased as fermentation progressed (a loss of 18.3% total polyphenols and 14.4% loss of total flavanols during fermentation) but some increases were observed in the final timepoints (120–168 h). Fermentation substrates, metabolites and putative cocoa bioactive compounds were monitored and found to follow typical trends for on-farm cocoa heap fermentations. For example, sucrose levels in pulp declined from >40 mg/mL to undetectable at 96 h. This model system provides a controlled environment for further investigation into the potential for optimizing fermentation parameters to enhance the flavanol composition and the potential health benefits of the resultant cocoa beans.
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    Flavanol Polymerization Is a Superior Predictor of α-Glucosidase Inhibitory Activity Compared to Flavanol or Total Polyphenol Concentrations in Cocoas Prepared by Variations in Controlled Fermentation and Roasting of the Same Raw Cocoa Beans
    Racine, Kathryn C.; Wiersema, Brian D.; Griffin, Laura E.; Essenmacher, Lauren A.; Lee, Andrew H.; Hopfer, Helene; Lambert, Joshua D.; Stewart, Amanda C.; Neilson, Andrew P. (MDPI, 2019-12-11)
    Raw cocoa beans were processed to produce cocoa powders with different combinations of fermentation (unfermented, cool, or hot) and roasting (not roasted, cool, or hot). Cocoa powder extracts were characterized and assessed for α-glucosidase inhibitory activity in vitro. Cocoa processing (fermentation/roasting) contributed to significant losses of native flavanols. All of the treatments dose-dependently inhibited α-glucosidase activity, with cool fermented/cool roasted powder exhibiting the greatest potency (IC50: 68.09 µg/mL), when compared to acarbose (IC50: 133.22 µg/mL). A strong negative correlation was observed between flavanol mDP and IC50, suggesting flavanol polymerization as a marker of enhanced α-glucosidase inhibition in cocoa. Our data demonstrate that cocoa powders are potent inhibitors of α-glucosidase. Significant reductions in the total polyphenol and flavanol concentrations induced by processing do not necessarily dictate a reduced capacity for α-glucosidase inhibition, but rather these steps can enhance cocoa bioactivity. Non-traditional compositional markers may be better predictors of enzyme inhibitory activity than cocoa native flavanols.
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    Inactivation of Salmonella enterica and Surrogate Enterococcus faecium on Whole Black Peppercorns and Cumin Seeds Using Vacuum Steam Pasteurization
    Newkirk, Jordan J.; Wu, Jian; Acuff, Jennifer C.; Caver, Chris B.; Mallikarjunan, Kumar; Wiersema, Brian D.; Williams, Robert C.; Ponder, Monica A. (Frontiers, 2018-08-07)
    Spices, including black pepper and cumin seeds, have been implicated in outbreaks of salmonellosis and prompted recalls of ready-to-eat products containing contaminated spices. Vacuum-assisted steam pasteurization is performed to improve the safety and quality of many low water activity products, however process parameters associated with inactivation on whole spices are not well described. The objective of this study was to determine the effectiveness of a lab-scale vacuum-assisted steam process for the inactivation of Salmonella enterica and its potential surrogate Enterococcus faecium ATCC 8459 inoculated onto the surface of whole peppercorns and cumin seeds. In addition, the effect of two inoculation preparation methods [growth on tryptic soy agar (TSA) or inclusion within a native microbiota biofilm], on the reduction of S. enterica serovars or E. faecium was compared on steam pasteurized whole black peppercorns. Spices were processed using steam under a vacuum to achieve a mean product temperature of 86.7 ± 2.8◦C for different dwell times. Salmonella inoculated using the TSA-grown method, required 83 and 70 s respectively to achieve a 5-log reduction of Salmonella on peppercorns and cumin seeds. Longer time periods were needed to achieve a 5-log reduction of Salmonella when it was present in a native biofilm on whole peppercorns. Survivor estimations were best predicted by the Weibull models. The mean log reductions of E. faecium were 0.9 log CFU/g lower than Salmonella on whole black peppercorns inoculated using the TSA-grown cells (P = 0.0021). The mean log reductions of Salmonella and E. faecium prepared using the biofilm-inclusion method were not significantly different (P = 0.76). E. faecium log CFU/g reductions were not significantly different compared to Salmonella on whole cumin seeds (P = 0.42) indicating that while reductions are comparable the surrogate may not always provide a conservative indication of complete Salmonella elimination for all spices processed using vacuum-assisted steam.