Other Assumptions
The food waste analysis undertaken in this study considers the entire US food system, which necessitates a number of reasonable assumptions. These assumptions are listed below, and a critical subset of the assumptions is subjected to a sensitivity analysis as described in the Results and Discussion section.
• The vast majority of the food consumed in the US is assumed to be produced in North America, except as indicated below. This is justified by the fact that nearly 99% of GHG emissions from the provision of food in the US are due to domestic production and value chain activities (Stolaroff, 2009).
• All meat product weights are boneless-equivalent (edible) weights as specified in the food availability data (USDA ERS, 2009).
• All fish and shellfish are assumed to be produced in North America through aquaculture. Tuna is wild caught in Europe and imported to the US.
• Typical food processing is included for all commodities that are listed in their processed forms in the food availability data (USDA ERS, 2009). Examples of such processed foods include fruit juices, canned and frozen vegetables and fruits, canned tuna, various meats and fish, milled flour, etc. About half of the 134 commodities in this study are processed in some way before entering the distribution stage. On the other hand, some commodities are listed in the data only in terms of the primary ingredients – additional processing steps are excluded from our analysis in such cases. These commodities mostly include processed grain products such as breakfast cereals, pasta and bread, which are listed in terms of the primary grains and flour.
• All fresh foods are stored (in refrigerators, freezers or otherwise) in distribution centers and retail stores for an average of 7 days before purchase.
• All food commodities are assumed to be transported an average of 2400 km within North America from production or processing locations to typical retail locations. Out of this, 2240 km are through semi-trailer trucks and 160 km through single-unit trucks. Tropical fruits are transported an additional 5000 km by ocean, and canned tuna is transported an additional 10,000 km by ocean. All transport modes include refrigerator or freezer compartments as needed.