CSS – Pathogen Free Fertilizer Products

January 15, 2016

California Safe Soil’s moves towards sustainable agriculture are becoming a main staple in McClellan Park in Spring 2016 with a new facility for H2H fertilizer and livestock feed production. The plant looks to bring the area to the forefront of the “Farm to Fork” movement with the mission to make a meaningful contribution to reducing food waste and improving agricultural productivity.

This technical article on Science Direct//Journal of Cleaner Production was originally published in July, 2015, concludes that the California Safe Soil processes adopted in a study for converting food waste into organic soil amendment (OSA) reduced the pathogen levels from 7 to 8 orders of magnitude to non-detectable levels, indicating that the final OSA product has minimal risk of pathogens. The food-waste recycling approach presented in this research produced OSA with organic matter and C: N ratio of 21% and 12:1, respectively. [Article Received 23 July 2015, Revised 8 September 2015, Accepted 11 September 2015, Available online 25 September 2015]

Field trials of strawberry plant growth showed that the plant growth was increased by 25% when the OSA was added with grower standard chemical fertilizer. We anticipate that the results presented in this article will help in improving the understanding of pathogen inactivation in food waste as well as improving the existing food waste recycling processes.

Food production in the U.S. uses approximately 50% of its land, and utilizes 80% of the total fresh water consumed. About 40% of total food production, however, goes as waste (Gunders, 2012), which is equivalent of $165 billion each year. In contrast, currently more than a billion people are chronically malnourished (Foley et al., 2011). In theory, the total food waste produced in North America and Europe can potentially feed the world's hungry three times over (Stuart, 2009). Alternatively, it can reduce the application of chemical fertilizers considerably if the use of soil amendment derived from food waste is adopted extensively.

Recycling food waste for producing products, such as OSA and bioenergy, has received a great level of interest recently. Organic waste treatment processes such as composting processes (i.e., windrow composting, vermicomposting, and powered composting) (VermiCo, 2013; Purkayastha, 2012; Munnoli et al., 2010; Shivakumar et al., 2009) and anaerobic digestion processes (Shin et al., 2010; Quiroga et al., 2014; Dai et al., 2013; Bernstad et al., 2013; Rounsefell et al., 2013) are promising technologies. Previous studies (Parthan et al., 2012; Broitman et al., 2012; Levis and Barlaz, 2011; Levis et al., 2010; Diggelman and Ham, 2006; Lundie and Peters, 2005; Ayalon et al., 2001) have assessed the waste treatment costs of the various treatment processes. Many factors including the application of the digestate (i.e., soil amendment), waste transport, gas collection and energy recovery, and the inclusion of environmental benefits are reported to influence the waste treatment costs. For example, Ayalon et al. (2001) suggested that the most cost-effective means to treat the degradable organic component for avoiding reducing CO2 is aerobic composting.  Another study by Levis and Barlaz (2011) assessed the various options of food waste treatment processes and estimated that anaerobic digestion was the most environmentally beneficial treatment option potentially because of avoided electricity generation and soil carbon storage from use of the resulting soil amendment. The authors also reported that a traditional landfill with energy recovery can have lower emissions than any of the composting alternatives when a fertilizer offset was used. Another study by Tsilemou and Panagiotakopoulos (2006) reported that anaerobic digestion and in-vessel composting are the most costly methods for solid waste treatment.

Although all above processes are applied for treatment the food waste and have numerous benefits, the fate of food-borne pathogens in these processes are not well understood. The presence of pathogens in an OSA can potentially recycle pathogens in agricultural systems (Holden and Treseder, 2013). Pathogens associated with growing plants have caused many food-borne outbreaks (Holden and Treseder, 2013; Hoffmann and Anekwe, 2013). The U.S. Department of Agriculture's Economic Research Service (USDA-ERS) estimates that pathogens in food cause 6.5e33 million cases of human illnesses, and the cost of these illnesses is greater than $4 billion (Buzby et al.,1996). A relatively new study by Hoffmann and Anekwe (2013) reported cost of food-borne illness in the USA ranging from $14.1 billion to $152 billion. Hoffman et al. (2012) estimated that 14 food-borne pathogens cause $14.0 billion in cost of illness. Approximately 90% of this loss is caused by five pathogens: Salmonella enterica, Campylobacter spp., Listeria monocytogenes, Toxoplasma gondii, and norovirus. Therefore, ensuring the destruction of these pathogens in the soil amendment, prior to application of soil amendment (derived from food waste) into crop land is crucial for protecting environment and mitigating human health risk.

Considering the enormous amount of food waste in global food supply chains (Papargyropoulou et al., 2014), additional research is needed to identify the processes capable of converting food waste into a safe and useful by-product such as OSA. Previous studies reported soil as an important source of pathogens such as Escherichia coli, which has been directly related to food-borne outbreaks (Perry et al., 2013; Bolton et al., 2011). In contrast to the OSA, ongoing excessive use of chemical fertilizers has lowered soil quality and leads to environmental degradation (Zhu et al., 2012). Since the global food production relies on soils (Lal, 2014; Blanco-Canqui and Lal, 2008), which are a finite resource, they require protection. Recently, the use of OSA has been seen as an alternative to chemical fertilizers, which enhance crop yield as well as promote the sustainable development of agricultural industry (Zhu et al., 2012). The goal of this research is to assess the inactivation of human pathogens in the process of converting food waste into OSA. The objectives of this study are to: 1) understand the impacts of enzyme digestion (55e57 C), pasteurization (75e77 C) and acidification processes on the inactivation of food-borne pathogens (E coli O157:H7, S. enterica subspecies enterica sv Typhimurium LT2, and L. monocytogenes) in the OSA; and 2) assess the yields and nutrient levels of OSA derived from food waste....

This is a detailed scientific study that describes evidence for the claims that California Safe Soil makes about its process and soilc amendment product H2H. Download and read the complete article here.

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