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U.S. Department of Health and Human Services

Science & Research

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Volume IV - 2.11 Canned Food and Can Seam Examination

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Orientation and Training

Food and Drug Administration



Section 2 - Microbiology


A.  Objective:

  1. To learn can classification, progressive decomposition, headspace gas, culturing, pH, water activity, direct smear, odor and appearance, etc.
  1. To distinguish between a Acidified and Low Acid Canned Food.
  1. To familiarize the trainee with other types of hermetically sealed containers, i.e., jars & pouches.
  1. To discuss 21CFR, Parts 113 and 114 (Low Acid Canned Food and Acidified Food Regulations).
  1. Assignment:


It is the trainer’s primary responsibility to transfer knowledge both practical and in theory related to sample analysis. This may be accomplished through a series of designated training samples. Once the trainer is confident that the trainee can successfully and independently perform the analysis, the trainee will be issued a series of training samples.

Read Bacteriological Analytical Manual (BAM) chapter 21 A. and B. and 22 A.-D., online at: http://www.fda.gov/Food/ScienceResearch/LaboratoryMethods/BacteriologicalAnalyticalManualBAM/ucm072694.htm

  1. Perform a complete canned food analysis, comprising each individual test on a representative number of low acid canned foods.
  1. Perform a pH and water activity analysis.
  1. Perform a complete canned seam tear down analysis.

C.  Questions:

  1. What is a Flipper, Springer, Hard Swell, and Soft Swell?
  1. What is flat-sour spoilage?  What bacteria can cause this?
  1. Does microbial spoilage of a food always result in a swollen can? Explain.
  1. Why are certain canned food media incubated at 55 degrees C.?
  1. Explain the microbiology and physical attributes of each of the following: under processing, leaker spoilage, hydrogen swell, overfill.
  1. Explain the construction of a metal can. Name the components of the double seam.
  1. Explain water activity and its significance in an acidified and low acid canned food.