Canadian Grain Commission
Symbol of the Government of Canada

Spoilage and heating of stored agricultural products


Most agricultural products in Canada are stored safely with minimal loss of quality. However, each year a small proportion of these products becomes spoiled or self-heated (spontaneously heated), resulting in degrading or other quality loss. Situations involving fire are very serious and may cause major losses of a product, damage to the physical plant, and human injury.

Some commodities are more susceptible to spoilage and self-heating than others, and this can lead to severe problems for those responsible for, but unfamiliar with, the handling and storage of such commodities. When spoilage or self-heating problems do occur it is often difficult to obtain information on how to solve them.

The objective of this manual is to provide some basic information on the causal factors of spoilage, self-heating, and self-ignition in stored agricultural products, on methods used for the prevention, detection, and control of such problems, and on the behavior and management of selected commodities in storage.

The manual is intended as a guide for farmers, elevator, mill, and warehouse managers, agricultural extension workers, and exporters in solving their storage problems. It is also intended to assist fire fighters, police officers, insurance adjusters, and occupational health and safety officers who currently must rely on widely scattered and often inadequate information for their decision making.

The manual is divided into two parts. Part I deals with changes that occur during storage; self-heating; effects of molds; prevention, detection, and control of spoilage and heating; safety; problem investigation; and legal aspects. Part II is devoted to detailed accounts of the storage characteristics of specific commodities.

Because documented cases of spoilage and heating problems are not readily available, the same mistakes in management may occur in isolation in different parts of Canada. It is hoped that this manual will become the catalyst of later editions by encouraging readers to document their experiences of heating and spoilage problems for the benefit of others.

Many persons provided information and advice during the preparation of this manual, including:

  • E. Dorge, Ste. Agathe, MB;
  • J. Elvidge, Vancouver, BC;
  • J. Davies, Halifax, NS;
  • R.A. Meronuck, St. Paul, MN;
  • H. Uustalu, Thunder Bay, ON;
  • J. van Loon, Winnipeg, MB, and I.K. Walker, Lyttelton, New Zealand.
  • C. Reading, Fire Protection Association, London, England, and M. Malyk, Cereal Research Centre, Agriculture and Agri-Food Canada, Winnipeg, MB, were most helpful in locating literature sources.
  • N.D.G. White, Cereal Research Centre, Agriculture and Agri-Food Canada, Winnipeg, MB, reviewed the manual in its entirety and provided some useful suggestions.

The following reviewed particular chapters and provided additional information:

  • M.G. Britton, G. Elias, C.F. Framingham, G. Henry, D.S. Jayas, S.J. Kirkland, A. MacDonald, J.R. Matheson, W.E. Muir, R.H. Nelles, J.R. Rogalsky, and N.D.G. White of Winnipeg, MB;
  • J. Davies, Halifax, NS;
  • R.A. Meronuck, St. Paul, MN; and J. Tuite, West Lafayette, IN. J. Irvine, Faculty of Law, University of Manitoba reviewed and rearranged the content of Chapter 9 from a legal viewpoint.
  • C. Letain, L. Reece, B. Snell, Research Centre, Agriculture Canada, Winnipeg, MB, entered numerous drafts on the word processor;
  • R. Sims of the same station produced the line drawings and photographs;
  • S. V. Balchin, Research Program Service, Research Branch, Agriculture and Agri-Food Canada, Ottawa edited the manual.

Grateful acknowledgment is made to the following for permission to reprint copyrighted and other material:

  • Table 1 and other citations from Official grain grading guide 1987 edition, Canadian Grain Commission;
  • Table 2 abstracted from Table of materials subject to spontaneous heating, National Fire Protection Association Publication 492;
  • Table 5 and Figs. 15 and 16 from Management of on-farm stored grain, University of Kentucky;
  • Table 10 from Gas poisoning on the farm, Agriculture Canada Publication 1688;
  • Part of Table 15 and text inserts from Drying and storage of agricultural crops, Van Nostrand Reinhold Company Inc.;
  • Part of Table 15 and Tables 16 and 17 from Drying and storing grains, seeds and pulses in temperate climates, Institute for Storage and Processing of Agricultural Produce;
  • Table 20 from Soybean storage in farm-type bins, Illinois Agricultural Experiment Station Bulletin 553;
  • Figs. 4 and 6 from Fire Safety with silos, Fire Protection Association;
  • Fig. 7 from Managing dry grain in storage, Midwest Plan Service;
  • Fig. 8 and text from Evaluation of a remote moisture sensor for bulk grain, Academic Press;
  • Fig. 10 from Catalog No. 80, Seedburo Equipment Co.;
  • Fig. 11 from Vana Industries, Winnipeg;
  • Fig. 12a and text from Grain handling and storage, Elsevier Science Publishers B. V., and G. Boumans;
  • Fig. 14 and text from Extinguishing a silo fire by nitrogen purging, Getreide Mehl & Brot;
  • Fig. 22 and text from Problems of storing grain from temperate climates in tropical countries...history, CS Publications Ltd.;
  • Fig. 23 and text from Spontaneous heating and the damage it causes... soybeans in Israel, Pergamon Journals Ltd.;
  • Fig. 24 and text extracts from Country guide; extract from Foam, CO2 and water used against deep fire in maize cargo, Unisaf Publications Ltd.;
  • Extract from Fungal deterioration of dried barley malt in international trade, C.A.B. International;
  • Text from NIOSH alert:
  • Request for assistance in preventing fatalities due to fires and explosions in oxygen-limiting silos, National Institute for Occupational Safety and Health (NIOSH);
  • Extracts from Storage of cereal grains and their products, American Association of Cereal Chemists Ltd.; text from Spontaneous heating of stored cotton seeds, S. Navarro;
  • Extract from Grain storage: Physical and chemical consequences of advanced spontaneous heating in stored soybeans, American Chemical Society;
  • Extracts from Marine fire prevention, fire-fighting and fire safety, Prentice-Hall lnc.;
  • Text from Fire investigation, Pergamon Books Ltd.;
  • Text from Detection of grain silo fires using thermography, AGEMA Infrared Systems;
  • Text from Handling commodities in transit, Sosland Publishing Company;
  • Extracts from Heated-air grain dryers and Grain aeration and unheated air drying, O.H. Friesen and Manitoba Agriculture; extract from Fishmeal strikes again, Hazardous Cargo Bulletin;
  • Extracts from Grain storage, University of Minnesota Press;
  • Extract from Alleged mycotoxicosis in swine: Review of a court case, Canadian Veterinary Journal.

This manual is dedicated to my wife. Carol, for her considerable encouragement and support during the project.