EC 705 April 2000 Acid, Acidified and Low-acid Foods Canning Guidelines for Food Processors Department of Food Science and Human Nutrition College of Agriculture, Forestry & Life Sciences Clemson University
Acid, Acidified and Low-acid Foods: Basic Canning Guidelines for Food Processors Commercial food processors are responsible for ensuring the safety of their products. Health hazards can occur if inadequate or improper manufacturing, processing or packaging is used in the production of low-acid and acidified canned foods. Therefore, food processors must be in compliance with regulations established by the Food and Drug Administration (FDA) and state agriculture and health departments across the country. Any commercial food manufacturer processing and packaging low-acid canned foods and acidified foods must register their processing establishment and must file processing information. This is done to comply with laws and regulations requirements. These regulations ensure consumer safety from undesirable microorganisms or their toxins, especially Clostridium botulinum. This microorganism produces a deadly toxin if it is not properly destroyed with good canning procedures that include a properly designed thermal process. Since filing processing information for low-acid foods and acidified foods is an FDA requirement, the processors may need to determine, among other factors, the ph and/or the water activity of the product. These two factors, at the proper safety level, are very important for protection against harmful bacteria. The safety level for ph is 4.6 or below and for water activity is 0.85 or below. Following are basic guidelines to determine if a food product is classified as acid, acidified or low acid. Based on this classification, a food processor needs to be aware of the specific FDA regulations to ensure legal compliance. SOME DEFINITIONS FROM 21 CFR (CODE OF FEDERAL REGULATIONS) Acid foods means foods that have a natural ph of 4.6 or below. Low-acid foods means any foods, other than alcoholic beverages, with a finished equilibrium ph greater and a water activity (aw) greater than 0.85. Tomatoes and tomato products having a finished equilibrium ph less than 4.7 are not classed as low-acid foods. Water activity is a measure of the free moisture in a product and is the quotient of the water vapor pressure of the substance divided by the vapor pressure of pure water at the same temperature. Acidified foods means low-acid foods to which acid(s) or acid food(s) are 2
added. These products include, but are not limited to, beans, cucumbers, cabbage, artichokes, cauliflower, puddings, peppers, tropical fruits and fish, singly or in any combination. They have a water activity (aw) greater than 0.85 and a finished equilibrium ph of 4.6 or below. These foods may be called, or may purport to be, pickles or pickled. Commercial processors includes any person engaged in commercial, custom or institutional (church, school, penal or other organization) processing of food, including pet food. Persons engaged in the production of foods that are to be used in the market or consumer tests are also included. ACID LEVELS (ph) Food ph Classification Most fruits Equal or less NATURALLY ACID Most peaches Most apples Most tomatoes Most orange juices Fresh fish Greater LOW-ACID Canned green beans Bread Fresh ham Most protein foods Most vegetables and starch-based foods Pickled foods Equal or less ACIDIFIED Source: Food Microbiological Control Manual, Federal and Drug Administration, 1998. WATER ACTIVITY Water activity is not exactly the same as the moisture content of a product. These two are different concepts. For example, a pizza crust may give the impression of being relatively dry, or having low moisture content, but its water activity may be above 0.85. Water activity levels of 0.85 and higher can promote the growth of contaminating bacteria. Food Moisture Level Water Activity Fresh salmon, apples, Moist foods Above 0.85 milk, bread Flour, jams, molasses, Intermediate-moisture foods Between 0.60 and 0.85 dried fruit Dried noodles, crackers Low-moisture foods Below 0.60 Adapted from Food Microbiological Control Manual, Federal and Drug Administration, 1998. 3
According to the FDA, all establishments engaged in the manufacture of Acidified Foods and Low-Acid Canned Foods (LACF) offered for interstate commerce in the United States are required by 21CFR Parts 108, 113 and 114 to register their facility with form FDA 2541, Food Canning Establishment Registration, and file scheduled processes for their products with forms FDA 2541a, Food Process Filing for all Methods Except Low-Acid Aseptic, and FDA 2541c, Process Filing for Low-Acid Aseptic Systems. These forms may be obtained via FAX, telephone or the Internet. Requests may be made to the following address: LACF Registration Coordinator, HFS-618 Food and Drug Administration Center for Food Safety and Applied Nutrition 200 C Street, S.W. Washington, DC 20204 Phone: (202) 205-5282, FAX: (202) 205-4758 In South Carolina: (803) 765-5845 Email address: lacf@vm.cfsan.fda.gov. By accessing the FDA Internet address, you may obtain more information on low-acid foods and acidified foods. The table on the following page provides guidelines for classifying food products based on ph and water activity and the corresponding FDA requirements regarding acidified and low-acid canned foods. Notice also that depending on a particular situation, the decision to establish which foods are acid or acidified is subject to interpretation by the appropriate regulatory agency. 4
And the equilibrium ph of the finished product is: And/or the water activity (aw) is: Then the product is: And the processor needs to comply with: Need to register and file process? Need certification training? If the product contains only naturally acid ingredients* Equal or less ACID If the product does contain any low-acid ingredients* Equal or less ACIDIFIED, 21 CFR 114 Regardless of product ingredients Greater Greater than 0.85 LOW-ACID 21 CFR110, 21 CFR113 Regardless of product ingredients Greater Less than 0.85 EXEMPTED FROM 21 CFR 113, 114 108.35 & 108.25 Regardless of product ingredients Equal or less than 0.85 EXEMPTED FROM 21 CFR 113, 114 108.35 & 108.25 If the finished product is refrigerated EXEMPTED FROM 21 CFR 113, 114 108.35 & 108.25 *There may be other particular situations where the terms acid or acidified would be subject to regulatory interpretation, especially when addition of small amounts of low-acid food(s) to acid foods do not significantly change the equilibrium ph of the finished product. Call the FDA or your Extension Office for more guidance. Notice: Laws and Regulations regarding Standards, Labeling, HACCP and others will still apply to your operations. Also seafood products may have additional HACCP regulations. 21CFR 110: Current Good Manufacturing Practice in Manufacturing, Packing, or Holding Human Food. 21CFR 108: Emergency Permit Control. 21CFR 113: Thermally Processed Low-Acid Foods Packaged in Hermetically Sealed Containers. 21CFR 114: Acidified Foods. 5
SOME COMMON PROCESSED FOODS T COVERED UNDER THE LOW-ACID FOOD REGULATIONS (21 CFR 113 AND 21 CFR 108.35 AND ACIDIFIED FOOD REGULATIONS: 21 CFR 114 AND 21 CFR 108.25) The following are some examples of foods that are not considered to be acidified foods or low-acid foods; therefore, commercial processors do T have to file and register their processing information for these products with the Food and Drug Administration (FDA). Acid foods (naturally acid foods have a ph of 4.6 or less) Acid foods (including such foods as standardized and non-standardized food dressings and condiment sauces) that contain small amounts of low-acid food(s) and have a resultant finished equilibrium ph that does not significantly differ from that of the predominant acid or acid food Alcoholic beverages Carbonated beverages Jams, jellies and preserves (21 CFR 150) Tomatoes and tomato products having a finished equilibrium ph less than 4.7 Fermented foods (the ph is reduced to 4.6 or less by the fermenting microorganisms) Foods that are T packaged in hermetically sealed containers Any food prepared under the continuous inspection of the meat and poultry inspection program of the Animal and Plant Health Inspection Service of the Department of Agriculture under the Federal Meat Inspection Act and the Poultry Products Inspection Act Foods that are stored distributed and retailed under refrigeration (A keep refrigerated statement must be conspicuously displayed on the label.) Foods with water activity of 0.85 or below Food that are not thermally processed
Food regulations in South Carolina are essentially the same as the FDA s regulations and the USDA s regulations (for meat and poultry products). The South Carolina Department of Agriculture (SCDA), Laboratory Division (telephone [803] 737-9690), is responsible for enforcing food (nonmeat or poultry) regulations in South Carolina. The South Carolina Meat and Poultry Inspection Service (telephone: [803] 788-2260) is responsible for enforcing meat and poultry regulations. The following commercial laboratories in the Southeast may be helpful in assisting food processing companies with food analysis: ABC Research Corporation, Gainsville, Florida, (904) 372-04336 Silliker Laboratories of Georgia, Stone Mountain, Georgia, (404) 469-2701. Southern Testing and Research Laboratories, Wilson, North Carolina, (919) 237-4175. Through the Clemson University Cooperative Extension Service, food processors in South Carolina can have access to a process authority recognized by the FDA that can help determine the classification of food products based on ph and water activity information. Prepared by Dr. Felix Barron, Extension Food Scientist, Food Science and Human Nutrition Department, Clemson University, 224 Poole Agricultural Center, Clemson, SC 29634-0371. The Clemson University Cooperative Extension Service offers its programs to people of all ages, regardless of race, color, sex, religion, national origin, disability, political beliefs, sexual orientation, marital or family status and is an equal opportunity employer. Clemson University Cooperating with U.S. Department of Agriculture, South Carolina Counties, Extension Service, Clemson, South Carolina. Issued in Furtherance of Cooperative Extension Work in Agriculture and Home Economics, Acts of May 8 and June 30, 1914 Public Service Activities