According to Official Guinness Records,
The largest cereal treat weighed 4,678.35 kg (10,314 lb) and was achieved by "MEGA BITES" Beyond Productions, Inc. in La Cañada Flintridge, California, USA, on 14 March 2010.
Ingredients in order of predominance: Marshmallows: 2,815.94 kg (6,208.08 lb), Rice Krispies®: 1,468.44 kg (3,237.36 lb), Salted butter: 393.97 kg (868.56 lb). Overall dimensions: 3.66 m long x 2.44 m wide x 2.13 m tall (12 ft x 8 ft x 7 ft). Food safety and wholesomeness was assured by the following: All manufacturing was done acording to USDA Good Manufacturing Practice as outlined in 21 CFR Part 110 - Current Good Manufacturing Practice In Manufacturing, Packing, or Holding Human Food. A HACCP plan was developed to ensure any potential hazard was eliminated, and implementation was monitored by a food safety expert. All ingredients utilized came from the channels of commercial comerce and are assured wholesome by the manufacturer. Any food contact surfaces were sanitized prior to contact including the mold which was coated in food grade plastic, cleaned to be free from visible dirt and sanitized directly prior to the food contact. The treat was covered completely when maufacturing was not active. The finished treat had a water activity of below 0.91aw and was stable at ambient temperature for the short time while it was being constructed and distributed. The entire platform and mold were built on top of 6 load cells which tied to a summing correlator, load cells were calibrated and certified by scalefx, scale was zeroed after assembly of the mold and prior to dumping of first batch. The mold was built in the shape of a 12'x8'x8' rectangle with framed 4'x8'x3/4" plywood on sides and back and 4'x8'x3/8" clear framed acrylic on the front. Total of 7 upright sheets of plywood made up the sides & back and 3 upright sheets of clear acrylic made up the front. 2"x4"x8' and 2"x4"x12' studs were used to frame and tie together walls. Free standing scaffold was built around 3 sides to allow for dumping of batches into mold. Stainless steel 12' long tamping poles were used to pack.
For a complete list of 2010 records, please visit 2010 Guinness Records in United States.