Electrolyzed oxidizing water treatment as a post-harvest process for controlling histamine formation in fish

Scombroid poisoning, caused by histamine intoxication, is one of the most prevalent illnesses associated with seafood consumption in the United States. The illness is usually accompanied with a variety of symptoms, such as rash, nausea, diarrhea, flushing, sweating, and headache. Incidence of scombroid poisoning has been consistently reported in the U.S. through surveillance and is often underestimated due to mild and transient symptoms. Histamine can be formed in fish through enzymatic decarboxylation of histidine. Many bacteria include Morganella morganii, Proteus vulgaris, Klebsiella pneumoniae, and Enterobacter aerogenes are known to be prolific histamine formers and have been frequently isolated from fish. Among them, Morganella morganii is the most prolific histamine former and plays the major role in histamine formation in fish that is improperly handled. The U.S. Food and Drug Administration's seafood regulations limit histamine in fish at a level of 5 mg/100g (50 ppm) for assuring the safe consumption of fish. This study was conducted to determine growth of histamine-producing bacteria (Enterobacter aerogenes, Enterobacter cloacae, Proteus hauseri, Morganella morganii, and Klebsiella pneumoniae) and histamine formation in yellowfin tuna (Thunnus albacares) stored at 5, 15 and 25°C as well as effects of treatments of electrolyzed oxidizing (EO) water and in ice form on reducing histamine-producing bacteria on food contact surfaces (ceramic tile and stainless steel) and fish skin (Atlantic salmon and yellowfin tuna). Enterobacter aerogenes and Morganella morganii were the most prolific histamine formers capable of producing >1,000 ppm of histamine in broth culture after 12 h at 25°C. Both species grew rapidly at elevated temperatures (15-25°C), but the growth was inhibited at 5°C. Histamine was produced by the bacteria in medium broth and tuna meat held at 15 and 25°C when bacterial populations increased to ≥10⁶ CFU/ml (or CFU/g). However, storing yellowfin tuna inoculated with M. morganii or E. aerogenes at 5°C resulted in slight decreases of the bacteria over 14 days of storage and no histamine formation. Low-temperature (≤5°C) storage was critical to prevent histamine formation in fish. Enterobacter aerogenes and Morganella morganii could survive well on food contact surfaces (glazed ceramic tile and stainless steel) and fish skin. However, a treatment of electrolyzed oxidizing (EO) water (50 ppm chlorine) for 5 min was capable of removing the bacteria completely from the surfaces (>1.7 to >5.4 log CFU/cm² reductions). Soaking salmon skin in EO water containing 100 ppm for 120 min could reduce E. aerogenes and M. morganii on salmon skin by 1.3 and 2.2 log CFU/cm², respectively. Holding fish skin in EO ice containing 100 ppm of chlorine for 24 h could reduce E. aerogenes by 1.6 log CFU/cm² on salmon skin and 2.4 log CFU/cm² on tuna skin and M. morganii by 2.0 log CFU/cm² on salmon skin and 3.5 log CFU/cm² on tuna skin. EO water can be used as a sanitizer for decontaminating histamine-producing bacteria on food contact surfaces. Holding fish in EO ice (100 ppm chlorine) could be used as a post-harvest treatment to reduce histamine-producing bacteria contamination on fish skin and decrease probability of histamine formation in fish during storage

Low-temperature depuration and low-temperature high hydrostatic pressure processing as post-harvest interventions for diminishing Vibrio parahaemolyticus contamination in oysters

Vibrio parahaemolyticus is a leading cause of acute gastroenteritis associated with consumption of seafood, particularly raw oysters. The United States Centers for Disease Control and Prevention (CDC) estimated that 45,000 cases of V. parahaemolyticus infection occur each year in the U.S. A recent CDC report revealed that the incidence of V. parahaemolyticus infection increased 76% when comparing 2011 level to 1996-1998 level. The aim of this research was to develop low-temperature depuration and low-temperature high pressure processing (HPP) as post-harvest means for decreasing V. parahaemolyticus contamination in oysters for safe consumption. Fresh Pacific oysters (Crassostrea gigas) were inoculated with a mixed culture (10⁵ MPN/g) of five clinical V. parahaemolyticus strains and depurated with UV-sterilized artificial seawater in a laboratory-recirculating system at refrigeration temperatures (2, 3, 7, 10, 12.5, and 15 °C) for 4 to 6 days. Depuration of oysters at 2 or 3 °C for 4 days did not result in significant reductions (P > 0.05) of V. parahaemolyticus in the oysters. However, depuration of oysters in 30-ppt seawater at 7 to 15 ºC for 5 days decreased populations of V. parahaemolyticus in oysters by >3.0 log MPN/g with no loss of oysters. Further studies revealed that the efficacy of depuration in reducing V. parahaemolyticus in oysters was influenced by water salinity with an optimum range of 20 - 30 ppt, but not types (diploid vs triploid) or sizes of oysters. The low-temperature depuration (10 - 12.5 °C, 25 ppt) can be applied as a simple and cost-effective treatment for reducing V. parahaemolyticus contamination in oysters. Investigation of the efficacy of low-temperature HPP in inactivating V. parahaemolyticus was conducted with clinical and environmental strains of V. parahaemolyticus strains in 2% NaCl solution or oyster homogenates subjected to pressure treatments (200, 250 and 300 MPa for 5 and 10 min) at 20, 15, 5 and 1.5 °C. Inactivation of V. parahaemolyticus cells by HPP was greatly enhanced by lowering processing temperature from 20 to 5 and 1.5 °C. A treatment of 250 MPa for 5 min at 1.5 °C resulted in complete inactivation (>6.4 log CFU/ml) of V. parahaemolyticus in culture suspension and oyster homogenates. This low-temperature HPP can be applied as a post-harvest process for complete elimination of V. parahaemolyticus from raw oysters for safe consumption. Studies of the mechanism of HPP for inactivating V. parahaemolyticus cells observed cell disruption, indicated by increased leakage of intracellular materials, after pressure treatments of 200 to 300 MPa for 5 and 10 min. Scanning electron microscopy imaging revealed a clear disruption of V. parahaemolyticus cells after a treatment of 300 MPa for 5 min. In addition, HPP caused protein denaturation as evidenced by decreases in protein and sulfhydryl contents of cellular proteins extracted from V. parahaemolyticus cells after pressure treatments. SDS-PAGE analysis of cellular proteins also demonstrated changes in protein profiles of the cells after pressure treatments. These observations suggest that inactivation of V. parahaemolyticus cells by HPP is associated with cell membrane damage and protein denaturation, which appear to be dependent on the strain and pressure applied in a treatment.Keywords: Food safety, Vibrio parahaemolyticus, Depuration, High hydrostatic pressure processing, Oyster

Reductions of Vibrio parahaemolyticus in Pacific Oysters (Crassostrea gigas) by Depuration at Various Temperatures

Consumption of raw oysters has been linked to several outbreaks of Vibrio parahaemolyticus infection in the United States. This study investigated effects of ice storage and UV-sterilized seawater depuration at various temperatures on reducing V. parahaemolyticus in oysters. Raw Pacific oysters (Crassostrea gigas) were inoculated with a mixed culture of five clinical strains of V. parahaemolyticus (10290, 10292, 10293, BE 98-2029 and 027-1c1) at levels of 10⁴⁻⁶ MPN/g. Inoculated oysters were either stored in ice or depurated in recirculating artificial seawater at 2, 3, 7, 10, 12.5, and 15 ºC for 4 to 6 days. Holding oysters in ice or depuration of oysters in recirculating seawater at 2 or 3 °C for 4 days did not result in significant reductions (P > 0.05) of V. parahaemolyticus in the oysters. However, depuration at temperatures between 7 and 15 ºC reduced V. parahaemolyticus populations in oysters by >3.0 log MPN/g after 5 days with no loss of oysters. Depuration at refrigerated temperatures (7-15 ºC) can be applied as a post–harvest treatment for reducing V. parahaemolyticus in Pacific oysters

eBay Strategic Analysis and Recommendation

The Internet has seen its share of success and failures as businesses try to understand how this new medium is going to be used in the 21st century. The eBay corporation has defined itself as not only a player on the Internet but as founders of a new business concept: online bidding and selling for the masses. Being first to market gives eBay some of the key strengths to make the most of this new medium. The key success factors such as a large customer base and a compelling environment online are allowing eBay to be profitable and be seen as a legitimate business. While large environmental changes in law and technology change the competitive landscape, eBay remains focused on being the largest and best Internet trading site available to a growing group on online users. However, the low barriers to entry make eBay an easy target for new competitors such as Yahoo and Amzon.com who are currently marketing in eBays space. Brick-and-mortar retailers and auction houses are attempting to understand this new marketplace where helping a housewife in Indiana trade Pez dispensers online is a profitable business plan. In the future, technological change could make any new business plan successful challenging not only eBay but also any business that doesn\u27t properly scan the competitive landscape. Current strategy says eBay should focus and grow its customer base through marketing and mergers. To date, the growth of eBay has been amazing with 100% + increases in sales from year-to year are expected. However, risks in managing such growth and maintaining the talent that will continue the growth are always on the minds of eBay\u27s management and shareholders. The slowing of this fast growing market will also be of vital concern as the first wave of the Internet revolution washes over the world. This group recommends that eBay diversify its customer and product base to minimize risks associated with too much reliance on its current product offering. Focusing on how and where the Internet is going to be utilized best will develop new technologies and markets. Alliances with major players inside and outside the internet will allow eBay to market its abilities to new customers as well as give them insight into what the next wave will look like and how to best take advantage of the changing tide of technology. At this point on the growth curve, eBay can become an industry standard or a memory. The execution and deliberate nature of their current and future strategy will determine if they are a Sony or an Atari

Reductions of Vibrio parahaemolyticus in Pacific oysters (Crassostrea gigas) by depuration at various temperatures

Consumption of raw oysters has been linked to several outbreaks of Vibrio parahaemolyticus infection in the United States. This study investigated effects of ice storage and UV-sterilized seawater depuration at various temperatures on reducing V. parahaemolyticus in oysters. Raw Pacific oysters (Crassostrea gigas) were inoculated with a mixed culture of five clinical strains of V. parahaemolyticus (10290, 10292,10293, BE 98-2029 and 027-1c1) at levels of 10(4-6) MPN/g. Inoculated oysters were either stored in ice or depurated in recirculating artificial seawater at 2, 3, 7, 10, 12.5, and 15 degrees C for 4-6 days. Holding oysters in ice or depuration of oysters in recirculating seawater at 2 or 3 degrees C for 4 days did not result in significant reductions (P > 0.05) of V. parahaemolyticus in the oysters. However, depuration at temperatures between 7 and 15 degrees C reduced V parahaemolyticus populations in oysters by > 3.0 log MPN/g after 5 days with no loss of oysters. Depuration at refrigerated temperatures (7-15 degrees C) can be applied as a post-harvest treatment for reducing V. parahaemolyticus in Pacific oysters. (C) 2012 Elsevier Ltd. All rights reserved