Development of Canning in the US
Development of canning in the U.S. dates back to May 15, 1862 when Abraham Lincoln signed into law the Agricultural Act that established the U.S. Department of Agriculture. The departmentís primary focus was to stimulate food production by providing seed and agricultural information to farmers and help them receive a fair price for their crops. Following the U.S. Civil War, westward expansion and development of refrigerated railroad cars spurred the growth of not only the livestock industry, but also meat packing and international trade. In response to the growing pressure from veterinarians, ranchers, and meat packers to eradicate livestock diseases in the United States, President Chester Arthur signed the Bureau of Animal Industry Act, which created the USDAís Bureau of Animal Industry (BAI) in 1884, effectively the true forerunner of FSIS. In 1905, the BAI faced its first challenge with the publication of Upton Sinclairís The Jungle. The ground breaking book exposed insanitary conditions in the Chicago Meat Packing industry, igniting public outrage, which eventually led to the establishment of continuous governmental inspection. Compared to salting fish, smoking and drying meats, or making salami type dried sausages, canning was a relatively new method of preserving food. Although small canning plants appeared in different areas of the country, the food was canned in all types of containers.
In 1901 canning becomes a big industry when Norton Brothers merged with 60 other firms to form the American Can Company (123 factories). In this emerging period, losses from spoilage, as well as from poor quality were accepted as normal. Refrigerators were not common yet and the convenience of storing food at room temperature far outweighed a little loss of quality. There was, however, a big problem: people got sick and often died, a fact that was not unnoticed and had to be dealt with.In response to both The Jungle and the Neill-Reynolds report, Congress passed the Federal Meat Inspection Act in June 1906. The Act allowed the USDA to issue grants of inspection and monitor slaughter and processing operations, enabling the Department to enforce food safety regulatory requirements. In 1910, the Meat Inspection Division established a research center in Beltsville, Maryland. Seven similar laboratories were later created throughout the country. These laboratories were responsible both for developing new testing methods and testing meat and meat products for foreign substances. A big problem was a lack of reliable formulations. In 1878 The Canning Trade magazine was created and it started publishing technical articles and the first formulas. In 1914 the best material was combined into one publication and the first edition of 'A Complete Course in Canning' was printed. In 1996 the 13th edition of 'A complete Course in Canning' was published. The work, still published by the Canning Trade Inc., has become the textbook for students, packing plants and anybody employed in the canning industry.
Farmer's Bulletin 359
The earliest USDA publication for home canning was the Farmerís Bulletin 359, issued in 1909 by the Bureau of Chemistry. A discussion of decay, as caused by molds, yeasts and bacteria, was included along with an explanation that air must be excluded not for its own damaging properties but to exclude bacteria. It was explained that proper sterilization required heat.The process recommended was fractional sterilization - ìthe whole secret of canning.î It recommended to heat the vegetable in the jar to the boiling point of water and maintain that temperature for 1 hour each for two or three successive days. The first day of boiling was to kill molds and almost all the bacteria, but not spores. The spores were thought to germinate upon cooling, and boiling the second and third days killed the new bacteria. If fractional sterilization was not practiced, about 5 hours of boiling on the first day was recommended.
Farmer's Bulletin 839
This was the next publication issued in 1917 by the States Relation Service which later became the Extension Service, 'Home Canning by the One-Period Cold-Pack Method.' Three basic processes were recommended for fruits, vegetables and meats: boiling water bath (212° F), water seal process (214° F), and steam pressure process. Steam pressure at 5-10 psi, pressure cooker at 10-15 psi. Screw top containers were recommended. This bulletin devoted much of the space to operating the canning equipment and less to the theory behind sterilization and spoilage, so a month later Home Canning of Fruits and Vegetables is issued.
Farmer's Bulletin 853
'Home Canning of Fruits and Vegetables' was issued in 1917. It explained the causes of spoilage such as molds, yeast, bacteria and spores, and enzymes. A distinction was made between sterilization (the killing of all microorganisms) and processing (heat treatment which kills vegetative cells but not spores).
Farmer's Bulletin 1211
Both farmerís Bulletins 839 and 853 were replaced in 1921 with 'Home Canning of Fruits and Vegetables', Bulletin 1211 (USDA 1921). The publication covered in detail the "whys" of processing and reasons for spoilage.
Canning Theory Development (1920-1925)
During those first experimental years there were numerous outbreaks of botulism caused by commercially canned products. To combat the growing problem, in 1923 USDA establishes Bureau of Home Economics where many experimental works on canning are performed. The recommendations are issued for canning vegetables (except tomatoes) in pressure canners, and water bath canners for fruits and tomatoes. Timetables were given for both pint and quart jars and tin cans. Until 1920 thermal processes were based on individual experiences rather than on scientific knowledge. The science of bacteriology was not yet developed enough to answer the needs of the growing canning industry. There was a growing library of literature on the thermal death point of microorganisms and spores of Cl. botulinum. Results of the research showed that the heat resistance of microorganisms was affected by pH, age of the spores, and sodium chloride.
This was a learning period and not all statements were true, for example USDA argued that the spores of Cl. botulinum were destroyed by heating for one hour at 175° F, 80° C. However, Burke (1919) concluded in her experiments that spores of Cl. botulinum will survive boiling for 3.5 hours; therefore, kettle canning is not a reliable method to sterilize material contaminated with bacterial spores. In 1921 Weiss showed resistance of Cl. botulinum spores to 212° F (100° C) for up to 5 hours and he demonstrated that the thermal death point of Cl. botulinum could be affected by temperature and time of exposure, syrup density, food consistency, and acidity of the food. As more proof became available, the USDA started to incorporate new knowledge into its home canning publications. In 1923 Charles Ball developed thermal death time formulas which relied less on empirical data. His formulas could be adapted to all can sizes and retort temperatures. His research become the standard for the United States Food and Drug Administration for calculating thermal processes in canning.
Adaptation Period (1926-1946)
Not much canning research was done in 1926-1939, however, between 1930-1935 plenty of studies were made on beef, other meats and chicken. The findings were incorporated as new recommendations into new publications.
National Canners Association Bulletin L-26
On January 18, 1930, the Board of Directors of the National Canners Association (now National Food Processors Association) approved for publication process suggestions for various low-acid foods packed in metal containers. The first edition of the Bulletin was published the same month. Whenever further data and information have become available, the Bulletin has been revised. Bulletin 26-L has proven itself to be extremely popular with the canning industry and the 13th edition was published in 1996.
Farmer's Bulletin 1762
In 1936 a new bulletin for canning fruits, vegetables and meats was issued. The processing times were calculated for 15 psi pressure (250° F, 121° C) and were provided for 1/2 pint and quart jars, and #2, #2.5 and #3 cans. Those new timetables for meat were in effect from 1935-1942. Those recommendations were for the most part in excess of the required processing as the 15 psi pressure (250° F, 121° C) was recommended.
Conservation Bulletin 28
In 1942, the U.S. Department of the Interior issued Conservation Bulletin 28, "Home Canning Fishery Products." It was strongly emphasized that ìunder no circumstances should any fishery product be canned unless a pressure canner is used. It is impossible to obtain a sufficient heat treatment or process, by any other means.
In 1943 USDA issues AWI-61, "Canning Tomatoes", and AWI-41, "Wartime Canning of Fruits and Vegatables" which superseded Farmers Bulletin 1762. In 1944, AWI-93, ìHome Canning of Fruits and Vegetablesî replaced AWI-41 and AWI-61. Oven canning was labelled "dangerous" due to ineffective and serious accidents. Open kettle canning was labelled as "wasteful" for fruits and tomatoes, "dangerous" for vegetables and was suggested only for preserves, pickles or other foods with enough sugar or vinegar to prevent spoilage. The timetable for fruits offered boiling water bath processes; for vegetables, pressure processes at 240° F, 116° C were recommended.The majority of current USDA process recommendations for low-acid foods (vegetables, meats, poultry, fish) are the result of three years of extensive research between 1944-1946. The earlier guides, for example an excellent Montana Extension Service No. 242 Bulletin "Canning Meat, Fish and Poultry" listed extremely safe procedures that called for long processing times at 250° F, 121° C. It was later deemed unnecessary and 240° F, 116° C temperatures were found satisfactory. The final findings were published in USDA bulletins:
AWI-110, USDA, 1945, "Home Canning of Meat." Processing instructions were given for canning in glass jars and metal cans.
AIS-64, USDA, 1947, "Home Canning of Fruits and Vegetables"
Home and Garden Bulletin No. 8, USDA, 1947, "Home Canning of Fruits and Vegetables."
A description of the research and the data were released in 1946 in Technical Bulletin No. 930 - "Home Canning Processes for Low-Acid Foods."
The latest USDA bulletin 539, Dec 2009, Complete Guide to Home Canning still lists 1946 original processing times for low-acid foods canned in glass jars. The United States Department of Agriculture tables for determining proper process times include processing times with altitude adjustments for each product. Process times for 1/2 pint and pint jars are the same as times for 1-1/2 pint and quart jars in the 1946 guide. For some products you have a choice of processing at 5, 10, or 15 PSI. In these cases, choose the canner pressure you wish to use and match it with your pack style (raw or hot) and jar size to find the correct process time. These guides should be studied as they are the best reference material for a hobbyist.
The National Canners Association was involved in establishing processing times and temperatures in USDA AWI-110, 1945, "Home Canning of Meat." The National Canners Association published its own bulletins:
Bulletin 26-L, Thermal Processes for Low-Acid Foods in Metal Containers, 1930, 13th edition in 1966.
Bulletin 30-L, Thermal processes for Low-Acid Foods in Glass Containers, 6th edition in 1991.
The National Canners Association has changed its name to the National Food Processors Association (NFPA) and in January 2005 it became the Food Products Association (FPA). Commercial packers that thermally process shelf-stable products in hermetically sealed containers must comply with the Food Safety and Inspection Service (FSIS) regulations on the canning of meat and poultry products - Title 9 of the Code of Federal Regulations: Part 318, Subpart G, and Part 381, Subpart X. The GMP regulations in the 21 CFR 108, 113, and 114 became effective May 15, 1979. These regulations are designed to prevent public health problems in low-acid and acidified low-acid canned foods. Low-acid canned animal foods are also regulated by the FDA with similar regulations and training requirements in the 21 CFR 507 and 508. Similar regulations, in the 9 CFR 318.300 and 381.300 for thermally processed meat and poultry products were implemented by the U.S. Department of Agricultureís (USDA) Food Safety and Inspection Service (FSIS) on June 19, 1987. FSIS requirements for training supervisors of thermal processing and container closure operations became effective on December 19, 1988.
A Complete Course in Canning
There is a book or rather ìworkî that has been perfected for over one hundred years and in our opinion it stands above others. This work is ìA Complete Course in Canningî that has been published by The Canning Trade Inc., Baltimore, Maryland since the 1900's. What has started as a single book, has become in time the two volume set, and then the three volume set of books. Of particular interests are the 9-12 (1970-1987) editions which were revised and enlarged by Anthony Lopez, PH.D., professor of food science and technology at Virginia Polytechnic Institute and State University at Blacksburg, Virginia and anything published later. The latest 13th edition (1996) has been edited by Donald L. Downing, PH.D., New York State Agricultural Experiment Station, Cornell University, Geneva, New York. This monumental work is a technical reference and textbook for students of food technology, plant managers, product research specialists, food equipment manufacturers and everybody who is professionally engaged in the canning trade. The complete set totals almost 2,000 pages and might be overkill for the average person, but it is of an immense value to a person that wants to master all aspects of canning or is contemplating his/her own canning business.