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This research aimed to assess how the partial removal of carbon dioxide affects fermentations to provide a better understanding of how the manipulation of carbon dioxide concentration can be used to optimize industrial fermentations. To achieve this, fermentation kinetics, fermentation metabolic products, and yeast stress indicators were analyzed throughout ongoing brewing fermentations conducted under partial vacuum with atmospheric pressure controls. The partial vacuum reduced the solubility of carbon dioxide in the media and decreased the time necessary to reach carbon dioxide saturation. The effect was an increased rate of fermentation, and significantly more viable cells produced under vacuum pressure compared to controls. Ethanol, glycerol, and volatile organic compound concentrations were all significantly increased under partial vacuum, while indicators of yeast stress (trehalose) were reduced. Additionally, as the number of yeast cells was higher under partial vacuum, less sugar was consumed per volume of yeast cell. This study measured fermentation kinetics, metabolic products, and yeast health to holistically assess the effect of partial vacuum during a batch fermentation and found significant differences in each that can be individually exploited by researchers and industry. Summary An exploration of batch yeast fermentation in a low-pressure environment, with a focus on the health and productivity of the yeast cells.

As part of the Food Safety on the Farm series, a collection that reviews the generally recognized principles of GAPs as they relate to produce, primarily at the farm level and with particular focus on fresh Florida crops and practices, this publication focuses on GAPs and GHPs relating specifically to water use. The publications in this series can be found online at the EDIS website at http://edis.ifas.ufl.edu/ topic_series_food_safety_on_the_farm. Introductionagricultural practices (GAPs) and good handling practices (GHPs) encompass the general procedures grow- ers, packers and processors of fresh fruits and vegetables should follow to ensure the safety of their product. GAPs usually deal with pre-harvest practices (i.e., in the field), while GHPs cover post-harvest practices, including pack- ing and shipping. This fact sheet covers GAPs and GHPs relating to water use. Seven other Florida Cooperative Extension factsheets will focus on other specific aspects of the GAPs program and how they relate to Florida crops and practices. Water is one of the most critical components of food safety on the farm and in post-harvest handling and processing. Water has the potential to transmit both chemical and biological hazards to fresh produce. It is used in every phase of operation: irrigation, transplant establishment, the application of pesticides and fertilizers, frost protection, product rinsing and washing, direct processing, facility cleaning, cooling operations, and personal hygiene for workers. The application of contaminated water at any of these points can introduce pathogens that could potentially reach the consumer.

Alcohols, aldehydes, ketones, amines, and sulfur compounds are essential aroma compounds related to fish flavor and spoilage. Gas chromatography-mass spectrometry (GC-MS) is an instrument that is widely used to identify and quantify volatile and semi-volatile compounds in fish products. In this research, a simple and accurate GC-MS method was developed to determine the aroma profile of mahi-mahi and tuna for chemical indicators of spoilage. In the developed GC-MS method, trichloroacetic acid (TCA) solution was used to extract analytes from homogenized fish samples. The purge and trap system was used for sample introduction, and the GC-MS with an RTX-Volatile Amine column was able to separate compounds without a derivatization procedure. The created purge and trap gas chromatography-mass spectrometry (PT-GC-MS) method could identify and quantify twenty aroma compounds in mahi-mahi (Coryphaena hippurus) and 16 volatile compounds in yellowfin tuna (Thunnus albacares) associated with fish spoilage. The amines (dimethylamine, trimethylamine, isobutylamine, 3-methylbutylamine, and 2-methylbutanamine), alcohols (2-ethylhexanol, 1-penten-3-ol and isoamyl alcohol, ethanol), aldehydes (2-methylbutanal, 3-methylbutanal, benzaldehyde), ketones (acetone, 2,3-butanedione, 2-butanone, acetoin), and dimethyl disulfide strongly statistically correlated with poorer quality tuna and mahi-mahi and were considered as the key spoilage indicators. PRACTICAL APPLICATION: A simplified and rapid purge and trap gas chromatography-mass spectrometry (PT-GC-MS) method developed in this research was able to identify and quantify important spoilage compounds in mahi-mahi and yellowfin tuna. This method is an efficient analytical method for determining volatile profiles of fish samples for industry analytical labs or the government. The identified analytical quality markers can be used to monitor the spoilage level of tuna and mahi-mahi.

HACCP is a food safety management system that is used in various segments of the food industry. The objectives of this 4-page fact sheet are to introduce the topic and to summarize the key components of a HACCP program. Written by J. A. Lepper, R. M. Goodrich-Schneider, K. R. Schneider, M. D. Danyluk and A. Sreedharan and published by the UF/IFAS Department of Food Science and Human Nutrition, January 2018. http://edis.ifas.ufl.edu/fs122