Dou, Zhengxia
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Publication Accelerating the Deactivation of Salmonella enterica Serovar Newport and Escherichia coli O157:H7 in Dairy Manure by Modifying pH or Temperature(2012-01-01) Toth, John D; Aceto, Helen W; Rankin, Shelley C; Dou, Zhengxia; DebRoy, ChitritaTo assess methods for control of disease-causing bacteria in animal manures prior to field application, we manipulated the temperature or adjusted pH of dairy manure to high (3.5 to 5) or low (10 to 12) values with aluminum sulfate or hydrated lime, and inoculated the manure with Salmonella enterica serovar Newport or Escherichia coli O157:H7, then incubated the manure at ambient temperature. At pH 4.2, S. Newport was eliminated within 6 days; however at pH >4.2 S. Newport was suppressed only temporarily and recovered to concentrations near the unamended controls. pH required to eliminate E. coli O157:H7 was 4.5. Both pathogens were killed by pH 11.0. The pathogens were eliminated within 2 weeks when inoculated manure was incubated at 37°C, whereas at 22°C and 4°C, the organisms persisted for much longer periods. S. Newport survived for over 300 days at 4°C, which has implications for manure spreading in colder seasons.Publication Conclusions and the Road Ahead(2014-12-09) Dou, ZhengxiaPublication Last Food Mile Conference Survey Results(2014-12-10) Finn, Steven M.; Dou, ZhengxiaFollowing The Last Food Mile conference in early December, we surveyed well over 150 participants to assess their impressions of the event and to glean information to help us shape future work on food wastage across the U.S. supply chain. Approximately one third of those surveyed responded.Publication Assessing U.S. Food Wastage and Opportunities for Reduction(2016-03-01) Dou, Zhengxia; Ferguson, James D; Galligan, David T; Kelly, Alan M; Finn, Steven M; Giegengack, RobertReducing food wastage is one of the key strategies to combat hunger and sustainably feed the world. We present a comprehensive analysis of available data, despite uncertainties due to data limitation, indicating that the U.S. loses at least 150 million metric tonnes (MMT) of food between farm and fork annually, of which about 70 MMT is edible food loss. Currently, <2% of the edible food loss is recovered for human consumption. A reasonably-attainable goal of food waste reduction at the source by 20% would save more food than the annual increase in total food production and would feed millions of people. This is an opportunity of significant magnitude, offering food security and resource and environmental benefits with few negatives. Seizing this opportunity requires technological innovation, policy intervention, and public outreach. This U.S.-based analysis is pertinent to other mid- to high-income countries.Publication An Assessment of Ammonia Emissions from Dairy Facilities in Pennsylvania(2001-01-01) Ferguson, James D; Dou, Zhengxia; Ramberg, Charles FA survey of 715 Holstein dairy farms in Pennsylvania was used to construct demographics for the average Holstein dairy farm. The average Holstein dairy farm was composed of 69 lactating cows; 11 nonlactating, pregnant cows; 44 heifers; and 18 calves. Milk production averaged 27.3 kg (60.0 lb). Crop area averaged 73.6 ha. Milk production, crop area and type, average county yields, and herd animal groups were used to construct a typical feeding program for these farms. Typical rations were constructed for six feeding groups (three milk production groups, one nonlactating group, two heifer groups) to meet milk production, pregnancy, and growth requirements. Rations were constructed based on three forage qualities (excellent, average, and poor) typically observed on Pennsylvania dairy farms. Data for animal description (milk production, body weight, growth, and pregnancy status) and ration components and amounts consumed for each animal group were input into the excretion model of the Dairy Nutrient Planner computer program (DNP). Excretion of fecal N and dry matter (DM), urinary N, and total P and K were produced for each animal group and used to assess potential volatile losses of N. Work at the Marshak Dairy, New Bolton Center, indicates the majority of urinary N is rapidly lost as ammonia from dairy facilities. Based on this observation, the losses of N as ammonia were estimated to be 4.63, 4.62, and 4.28 tonne/year for the farm with excellent, average, and poor quality forages, respectively. Volatile losses of N may be reduced most by controlling levels of urea in urine. Urinary N may be reduced through dietary manipulation of protein and carbohydrate sources. Conversion of urea to ammonia may be reduced by altering the pH of barn floors and gutters. Entrapment of ammonia may be accomplished by acidification of manure slurry. Atmospheric ammonia contributes to acid rain, eutrophication of estuaries and lakes, and particulate air pollution. Reduction of ammonia emissions from dairy barns can significantly reduce atmospheric pollution and improve air and water quality.