Chapter 15 - Low-Acid and Acidified Low-Acid Foods in Hermetically Sealed Containers (Canned Foods)
15.2 Definitions

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For the purpose of this code:

15.2.1 Acidified low-acid food

means a low-acid food which has been treated in a manner so that all components have attained an equilibrium pH of 4.6 or below by the time thermal processing and cooling is completed.

15.2.2 Aseptic processing and packaging

means the filling of a commercially sterile product into commercially sterile containers followed by hermetic sealing in a commercially sterile atmosphere.

15.2.3 Bleeder

means a small orifice through which steam and other gases are permitted to escape from a retort throughout the entire thermal process and may also serve as a means of removing condensate.

15.2.4 Canned food

means commercially sterile low-acid or acidified low-acid food packed in hermetically sealed containers.

15.2.5 Cleaning

means the removal of food residues, dirt, grease or other objectionable material.

15.2.6 Code lot

means all products have an identical code. Code lots should be restricted to the same product type (formulation), container type and size and processed in the same establishment during a period not to exceed 24 hours.

15.2.7 Come-up-time

means the time, including venting time, which elapses between the introduction of the heating medium into the closed retort and the time when the temperature in the retort reaches the required sterilization temperature.

15.2.8 Commercially sterile

15.2.8.1 Food means the condition obtained in a food which has been processed by the application of heat, alone or in combination with other treatments, to render the food free from viable forms of microorganisms, including spores, capable of growing in the food at temperatures at which the food is designed normally to be held during distribution and storage.

15.2.8.2 Equipment and containers used in aseptic processing means the condition obtained by the application of heat or other appropriate treatments which render the product contact surfaces of such equipment and containers free from viable forms of microorganisms capable of growing in a food, at temperatures at which the food is designed normally to be held during distribution and storage.

15.2.8.3 Atmosphere means the condition obtained by the application of heat, or other appropriate treatments, which render the atmosphere free from viable forms of microorganisms capable of growing in a low-acid food packed in hermetically sealed containers at temperatures at which the food is designed normally to be held during distribution and storage.

15.2.9 Critical factor

means any characteristic, property, condition, aspect or other parameter, variation of which may affect the attainment of commercial sterility.

15.2.10 Disinfection

means the reduction, of the number of microorganisms (to a level that will not lead to harmful contamination of food) by means of chemical agents and/or physical methods without adversely affecting the food.

15.2.11 Equilibrium pH

means the condition attained in an acidified low-acid food product in which there is no further change in the pH of any of the components.

15.2.12 Flame sterilizer

means an apparatus in which food in hermetically sealed containers is agitated at atmospheric pressure, by either continuous, discontinuous or reciprocating movement over gas flames to achieve commercial sterility of the food. (A holding period may follow the initial heating period.)

15.2.13 Heating curve

means a graphical representation of the temperature change in the food with time throughout the thermal process. (This is usually plotted on semi-log graph paper so that the temperature on an inverted log scale is plotted against time on a linear scale.)

15.2.13.1 Broken heating curve means a heating curve which shows a distinct change in the rate of heat transfer such that the curve may be represented by two or more distinct straight lines after the retort has attained the sterilization temperature when plotted on semi-log paper.

15.2.13.2 Simple heating curve means a heating curve which approximates a straight line after the retort has attained the sterilization temperature when plotted on semi-log paper.

15.2.14 Head space

means the volume in a container not occupied by the food.

15.2.14.1 Gross head space is the vertical distance between the level of the product (generally the liquid surface) in an upright and rigid container and the top edge of the container (the top of the double seam of a can or the top edge of a glass jar).

15.2.14.2 Net head space of a container is the vertical distance between the level of the product (generally the liquid surface) in an upright rigid container and the inside surface of the lid.

15.2.15 Hermetically sealed container

means a container, designed and intended to be secure against the entry of microorganisms including spores.

15.2.15.1 Rigid container means that the shape or contours of a filled and sealed container are neither affected by the enclosed product nor deformed by an external mechanical pressure of up to 70 kPa (10 psi, i.e., normal firm finger pressure.)

15.2.15.2 Semi-rigid container means that the shape or contours of a filled, sealed container is not affected by the enclosed product under normal atmospheric temperature and pressure but can be deformed by an external mechanical pressure of less than 70 kPa (10 psi, i.e., normal firm finger pressure.)

15.2.15.3 Flexible container means that the shape or contours of a filled, sealed container are affected by the enclosed product.

15.2.16 Holding time:

see sterilization time.

15.2.17 Incubation tests

means tests in which thermally processed product is kept at a specific temperature for a specified period of time in order to determine if outgrowth of microorganisms or other problems occur under these conditions.

15.2.18 Initial temperature

means the product temperature of the coldest container to be processed at the time the sterilization cycle begins.

15.2.19 Low-acid food

means a food, other than an alcoholic beverage, where any component of that food has a pH greater than 4.6 and a water activity (aw) above 0.85.

15.2.20 Potable water

means water fit for human consumption.

15.2.21 Retort

means a pressure vessel designed for thermal processing of food, packed in hermetically sealed containers, by an appropriate heating medium and where necessary with super-imposed pressure.

15.2.22 Scheduled process

means the thermal process alone or in combination with critical factors chosen by the processor for a given product formulation, container type and size and thermal processing system to achieve at least commercial sterility of the product.

15.2.23 Seals

means those parts of a container or container material that are joined or fused to form a hermetic closure.

15.2.24 Sterilization temperature

means the temperature maintained throughout the thermal process which is at least equal to that specified in the scheduled process.

15.2.25 Sterilization time

means the time between the moment sterilization temperature is achieved and the moment cooling is started.

15.2.26 Thermal process

means the thermal treatment required to achieve commercial sterility and is quantified in terms of time and temperature.

15.2.27 Vents

means openings in the retort shell controlled by a gate, plug cock, or other adequate valves and are used for the elimination of air from the retort during the venting period.

15.2.28 Venting

means the thorough removal of air from steam retorts through the vents by introduction of steam or other appropriate methods prior to attainment of the sterilization temperature.

15.2.29 Water activity (aw)

means the ratio of the water vapour pressure of a food to the vapour pressure of pure water at the same temperature and pressure.

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