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Current Home Canning Practices in the U.S.

E. L. Andress1, E. M. D'sa2, M. A. Harrison2, W. L. Kerr2, J. A. Harrison1, and B. A. Nummer1. (1) Dept. Foods and Nutrition Extension, University of Georgia, 208 Hoke Smith Annex, Athens, GA 30602, (2) Dept. Food Science and Technology, University of Georgia.

Paper 46B-3. Presented at the Institute of Food Technologists Annual Meeting Anaheim, CA, June 17, 2002.

Abstract

Home canning is a traditionally popular means of preserving seasonal produce or specialty foods. The last comprehensive survey of practices conducted by USDA was in the 1970s. Significant lapses in appropriate techniques were documented and later survey reports by others have not revealed major shifts toward improved practices. Computer listservs and the large commercial book industry have the potential for more widespread sharing of traditional and possibly unsafe techniques than ever before.

The objective was to conduct interviews with individuals primarily responsible for household food preparation, to determine their activity level in home canning and use of critical safety practices.

Between October 24, 2000 and January 10, 2001, trained interviewers at the Survey Research Center, University of Georgia, recorded 135 complete telephone interviews from households randomly selected across the nation. The 38-item interview included questions about the respondent's source of canning instructions, methods used, types and quantities of foods canned, containers and equipment used, equipment testing procedures, success of canning procedures and spoilage.

Survey results indicated that friends or relatives (48%) and cookbooks (19%) were the most popular sources of canning instructions. Vegetables were canned by 71%; tomatoes/tomato products by 60%; and fruits by 47%. The boiling water canner was the most frequently used processing method with 58% and 39.5% using it to can fruits (including tomatoes) or vegetables respectively. A pressure-based canner was used by 34% and 49% using it to can fruits or vegetables respectively. Only 24% had the dial gauge on their pressure canner tested. Recommended jars were used by 74%. Only 5.2% reported spoilage of home canned foods.

Greater adoption of science-based home canning techniques is still needed by consumers, particularly in the selection of appropriate processing temperatures, equipment and supplies. Findings document practices and knowledge that should be targeted in educational programs.

Introduction

Home canning has been a popular means of preserving seasonal produce or specialty foods for over a century. The level and type of related activity has shifted up and down throughout this time due to society and family economic conditions, war efforts, weather conditions and interest in duplicating what is available in the commercially processed food supply. Many of today's home canners are interested in being creative and view home canning as an art as much as a science (4). Though diverse recipes provide variety to people, the maintenance of safe practices in canning cannot be over-emphasized. If done improperly, home canning can lead to foodborne illness and even death, as well as economic losses from spoiled food.

Since the late 19th century, the USDA has published recommendations for home canning processes, pickling of foods, and sugar concentrates (jam and jelly products). Since that time the public as well as the Cooperative Extension System and home canning equipment manufacturers have continued to rely on the USDA for guidance. Scientifically-based methods for control of bacteria and calculation of sterilization processes for canned foods were developed in the first part of the 20th century. These methods and later refinements have been applied to the science of USDA home canning recommendations since the mid-1940s.

The number of books on home preserved specialties in the commercial printing industry, prevalence of listservs and other internet-based sharing of home canning directions, numbers of individual inquiries received by the Cooperative Extension System and other indicators support the fact that there are active home canners today (4). A review of these same sources, however, reveals that there is also transfer of non-scientific or high-risk directions for home canning and processing of foods occurring frequently.

The last comprehensive surveying of home canning practices conducted by USDA was in the 1970s (1,3). Significant lapses in appropriate techniques were documented at that time. More recent information about home canning practices has only been obtained from other sources in limited amounts (2,4). Because there is evidence that people are canning food at home (2,4) but there is little recent documented information on their actual practices, a national survey seemed in order.

Objectives

To conduct a national survey of U.S. households routinely practicing food preservation techniques:

  • To determine the extent of current home canning activity;
  • To identify contemporary home canning techniques being practiced, as well as types and quantities of foods being canned;
  • To identify risky practices requiring attention by educators and researchers.

Methodology

The National Center for Home Food Preservation (NCHFP) at The University of Georgia (UGA) developed a questionnaire and contracted with the Survey Research Center at UGA to conduct a national telephone survey. The survey instrument was comprised of 38 closed or open-ended (5) questions aimed at obtaining detailed information about individuals' home canning practices plus additional questions on home freezing practices. Respondents were provided with the option of choosing more than one appropriate response for some questions. The study conducted 501 interviews from randomly selected households across the nation, with all households having a near-equal chance of being selected for inclusion in the sample. Between October 24, 2000 and January 10, 2001, a total of 5,259 numbers were called; and 1,244 eligible adult interviewees were contacted. The final cooperation rate was 40.3% (501 interviews). The 501 interviews yielded 135 complete interviews of those canning food at home. To insure quality control of the interviewing process, interviewers were trained, and approximately one-fifth to one-quarter of the interviews were monitored, thereby eliminating interviewer errors.

Results

Who is canning?

  • 27% of individuals contacted in the survey reported canning food at home in the previous year; 91% of these said that they planned to can food the following year.
  • Only 10% of these home canners canned extra food in preparation for Y2K; those who did canned beans, tomatoes, vegetables, fruit and jams.
  • About half of home canners are between 35-64 years of age; 23% are 65 and over, and 24% are under 35 (Figure 1).
  • Figure 1. Age distribution of respondents in years
    Pie chart showing age distribution of respondents in years.

  • 82% of respondents were female, 56% were from Metropolitan statistical areas, and 52% were employed during the preceding year, either year-round (72%), for 26-51 weeks (21%) or for less than 26 weeks (4%).
  • Most home canners have at least a high school education; 28% have at least a 4-yr college degree (Figure 2).
  • Figure 2. Educational level of respondents
    Pie chart showing educational level of respondents.

  • More than half of home canners live in 2-4 person households (Figure 3). 60% of these households had no individual under the age of 18-yrs, while 19% had one under-18 yr old, and 8% had either 2 or 3 under-18s.
  • Figure 3. Size of households with home canners
    Bar chart showing the size of households with home canners.

  • Participation in home canning does not appear to be related to income, but there was a fairly high non-response rate to this question (Figure 4).
  • Figure 4. Annual income level of respondents
    Pie chart showing annual income level of respondents.

  • 84% of respondents were 'White', 6% African-American, 2% each Asian/Pacific-Islander or Native American and 4% described themselves as multi-racial.
  • 39% of respondents were located in the South, 30% in the North East, 18% in the North Central region and 13% in the West.

What are their sources of information?

  • About half obtain their canning instructions from friends or relatives (Table 1):

  • Table 1. Sources of home canning instructions
    Source % of respondents using
    Friends or relatives 49
    Cookbooks 19
    Canning jar/lid manufacturer inserts 10
    Pressure cooker/canner manufacturer 9
    USDA publications 3
    Extension Service publications 2
    Other 25

  • The 'other' sources included canning books (6 respondents), instructions that came with the purchase of fruit (1 respondent) and the internet (1 respondent).
  • 67% of respondents used their canning instructions 'as is', while 29% adapted the instructions for their individual use.

What are they canning and how?

  • 71% canned vegetables, 60% canned tomatoes/tomato products and 47% respondents canned fruits. Figure 5 represents the canning methods used by respondents who canned fruits (including tomatoes) and vegetables.

  • Figure 5. Methods used to can fruits and vegetables
    Bar chart showing the percentage of respondents who used different methods of canning.


  • Table 2 represents the types and quantities of food items canned.
Table 2. Amounts of various foods canned at home.
  % respondents (n=135) who canned quantities of
Food 1-10 pints 11-50 pints 51-100 pints >100 pints
Fruits 8 28 4 3
Tomatoes 10 33 7 4
Tomato sauce 7 10 1 0
Vegetables/Vegetable mixes 15 40 7 4
Soup mixtures 5 6 0 0
Pickles/Pickled vegetables 16 15 6 2
Pickled fruits 2 0 0 0
Jams/Jellies 22 27 2 0

Equipment Use and Management

  • Approximately one out of four respondents who used a pressure canner (n=54), had the dial gauge tested in 1999. Eleven percent have a pressure canner without a dial gauge.
  • One out of every five using pressure canners (n=54) reported making altitude adjustments in processing, and 12% (n=69) of those using boiling water canners made altitude adjustments. Approximately 11% and 15% (for pressure/boiling water, respectively) reported that such adjustments were not necessary.

Jars and Lids

  • Approximately 74% used home canning jars with 2-piece lids, 17% used recycled jars from commercially canned foods (e.g., peanut butter, salad dressing jars), and 14% used older-type home canning jars with rubber rings. 4% of respondents used metal cans.
  • 38% of respondents reported jars that did not seal properly after the canning process.
    • 13 people reported one improperly sealed jar, 10 reported two.
    • Individuals with improperly sealed jars (n=51) either discarded the food in these jars (41%), refrigerated them and consumed the food quickly (29%) or reprocessed them (24%). Only one respondent reported freezing the contents of the improperly sealed jars.

Food Storage and Use

Practice % respondents (n=135)
Maximum time Home canned food is stored.
- More than 12 months 37
- 6-12 months 47
- Less than 6 months 14
 
How home canned vegetables are prepared and served
- Bring to a boil before using 38
- Boil uncovered for 10 min or more 33
- Warmed in microwave 16
- Serve 'as is' with no further heating 13
- Heat in an oven 6
  • In response to a question posed about whether home- or commercially-canned foods could be spoiled without any visible sign of spoilage, 53% replied in the affirmative.
  • 93% respondents reported no spoilage in their home-canned foods. Among the seven respondents who did report spoilage, the items involved were pickles, marinated/pickled peppers and vegetables (two respondents each).

Summary

  • Greater adoption of science-based home canning techniques by many home canners is needed.
  • Little can be discerned about the science base of many instructions being used, as family and friends are cited as the source. It was not determined what the ultimate sources of those directions are. The USDA and Extension Service do not have large recognition as the cited source, although it is possible that family, friends, cookbooks and manufacturers are using the same instructions. The fact that 29% feel free to adapt the instructions they do have could be cause for concern, also.
  • One finding of greatest concern is the lack of pressure-based processing temperatures for low-acid foods. This survey did not determine if correct time/temperature combinations are being used for all foods, but the fact that vegetables are being canned at boiling water temperatures or without any processing (open-kettle) is enough to know those people are at high risk for foodborne illness, including botulism.
  • Altitude adjustments in processing temperatures or times are most likely not always being made when necessary.
  • Findings document risky practices and knowledge that should be targeted in educational programs and publications.

References

  1. Davis, C.A., and L. Page. 1979. Practices used for home canning of fruits and vegetables. USDA Home Economics Research Report No. 43. Washington, DC: Government Printing Office.
  2. Getty, V. and Evers, B. 1997. Activity profile of home canners. Electronic Food Rap, Vol. 7(40). http://www.sfu.ca/~jfremont/homecanning.html. Accessed on June 1, 2002.
  3. Hatfield, K.M. 1981. Changing home food production and preservation patterns. National Food Review 27:22-25.
  4. National Center for Home Food Preservation. 1999. Information collected from the Cooperative Extension System, cookbooks and internet. Unpublished data. Athens, GA: The University of Georgia.

This material is based upon work supported by the Cooperative State Research, Education, and Extension Service, U.S. Department of Agriculture, under Agreement No. 00-51110-9762.

Document Use:

Permission is granted to reproduce these materials in whole or in part for educational purposes only (not for profit beyond the cost of reproduction) provided the authors and the University of Georgia receive acknowledgment and this notice is included:

Reprinted with permission of the University of Georgia. Andress, E.L., E.M. D'sa, M.A. Harrison, W.L. Kerr, J.A. Harrison and B.A. Nummer. 2002. Current home canning practices in the U.S. Athens, GA: The University of Georgia, Cooperative Extension Service.

References to commercials products, services, and information is made with the understanding that no discrimination is intended and no endorsement by the University of Georgia, U.S. Department of Agriculture and supporting organizations is implied. This information is provided for the educational information and convenience of the reader.

The University of Georgia and Ft. Valley State University, the U.S. Department of Agriculture and counties of the state cooperating. The Cooperative Extension Service, the University of Georgia College of Agricultural and Environmental Sciences offers educational programs, assistance and materials to all people without regard to race, color, national origin, age, sex or disability. An Equal Opportunity Employer/Affirmative Action Organization Committed to a Diverse Work Force.

Contact:

National Center for Home Food Preservation
208 Hoke Smith Annex
The University of Georgia
Athens, GA 30602-4356

Tel: (706) 542-3773
Fax: (706) 542-1979
Web: http://www.homefoodpreservation.com

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