Focused specifically on Preventive Controls, Chapter 4 of the PC Rule Draft Guidance is intended to help industry identify, implement, and monitor preventive controls as required by the Preventive Controls rule for Human Foods (PCHF). The chapter begins with an overview of common preventive controls, but FDA notes that the chapter does not provide all the details needed because facilities have the flexibility to identify and implement preventive controls from among all procedures, practices, and processes that would provide assurances that the hazard is controlled (i.e., significantly minimized or prevented). Noting that preventive controls must be written, and can be CCPs and other controls that are appropriate for food safety, FDA defines them as “those risk-based, reasonably appropriate procedures, practices, and processes that a person knowledgeable about the safe manufacturing, processing, packing, or holding of food would employ to significantly minimize or prevent the hazards identified by the hazard analysis that are consistent with the current scientific understanding of safe food manufacturing, processing, packing, or holding at the time of the analysis.”  Remember this is not the same as HACCP, so you don’t need to find CCPs for all the preventive controls that you feel you need to put in place. Additionally, preventive controls include, as appropriate, process controls (4.3), sanitation controls (4.4), food allergen controls (4.5), supply-chain controls (4.6), recall plans (4.7) – each of which the chapter addresses in detail in the section noted herein in parentheses. Because of the extent of this chapter, this newsletter will focus on Process Controls as preventive controls, with the others to be addressed in upcoming newsletter(s). Process Controls. Process controls include procedures, practices, and processes to ensure the control of parameters during operations such as heat processing, acidifying, irradiating, and refrigerating foods. As appropriate, process controls must include parameters associated with the control of the hazard; and the maximum or minimum value, or combination of values, to which any biological, chemical, or physical parameter must be controlled to significantly minimize or prevent a hazard requiring a process control. For example, these could be time, temperature, flow rate, line speed, weight, thickness or size, viscosity, moisture level, water activity, salt concentration, pH, etc. Essentially, if a process parameter does not meet a minimum or maximum value or critical limit, the process is not in control and potential exists for producing an unsafe product. FDA notes a number of resources that can help in the specifying of processing parameters, but cautions care in their use as there can be differences in their application to your specific product and process, requiring the need to adjust to or account for those differences. FDA details guidance on a variety of treatments that are lethal to biological hazards, including: Heat Treatment (Thermal Processing) may provide commercial sterility (e.g., low temperature and pH enabling a shelf-stable product) or may reduce microbial pathogens but not provide for commercial sterility/shelf-stable product (e.g., pasteurization). As a part of this, the guidance discusses thermobacteriology (the relationship between bacteria and heat) in depth – of which, it says, one must have a basic understanding to design a lethal heat treatment. Lethal heat treatments that are discussed include cooking and emerging thermal effect technologies (microwave, radio frequency, ohmic heating, and inductive heating). Additionally, forthcoming guidance Chapter 6 will focus on the use of heat treatments as a process control. High-Pressure Processing. Because microorganisms vary in their sensitivity to high pressure, FDA recommends that you consider the organism of concern, product characteristics and, whether the process is to result in product that is to be refrigerated or that which will be shelf stable. For example, C. botulinum is one of the most pressure-resistant and hazardous microorganisms, so the best candidates for HPP continue to be acid foods and foods that will be refrigerated following processing. Irradiation. The application of radiation treatments for food safety or extended shelf life can be ionizing and non-ionizing, but because ionizing is a commonly used a lethality process control, it is the focus of the section. Irradiation, whether by Gamma rays, X-rays, or electronic beam, is considered to be a food additive in the U.S. and, as such, its use in foods requires premarket approval by FDA. The guidance includes a listing of approved uses for the treatment of food using ionizing radiation and the limitations. Antimicrobial Fumigation. The guidance specifies this use for almond treatment in California, with reference to the Almond Board of California funded research projects demonstrating that fumigation with propylene oxide (PPO) is an effective treatment for achieving a minimum 4-log reduction of Salmonella in almonds. Time/Temperature Control. With temperature being an essential factor that affects the growth of bacteria, FDA discusses the temperature ranges of growth for four types of bacteria (thermophiles, mesophiles, psychrophiles, and psychrotrophs), noting that most pathogenic bacteria are mesophiles for which the optimum growth temperature corresponds to human body temperature. Additionally, typically, the higher the temperature, the more rapid the growth of the microorganism. As such, the section discusses this in relation to refrigeration, cooling after cooking, and freezing. (The use of time/temperature control as a process control also is to be the topic of FDA’s upcoming Chapter 7.) Product Formulation. While most food preservation techniques used by processors employ knowledge of factors (such as water activity, pH, temperature, nutrients, chemical inhibitors, competitive microflora, and atmosphere) that affect the growth of bacteria, FDA focuses the section on factors that are frequently used as formulation process controls – water activity (aw), pH, and preservatives. The section explains defines and explains water activity and classifies foods and control requirements based on their water activity (high, medium, low). Later in the chapter, FDA then discusses the two primary methods of reducing water activity; by product formulation and by dehydration. It also discusses pH (acidity) in-depth, noting growth-limiting pH ranges for microorganisms, but explaining that lowering the pH is considered primarily a method of inhibiting the growth of bacteria rather than a method for killing bacteria. Although many microorganisms held at low pH for an extended time will be killed, processors should keep in mind that some pathogenic bacteria, in particular E. coli O157:H7, can survive acidic conditions for extended periods of time, even if their growth is inhibited. But because an acid pH can inhibit the growth of many bacteria, acidification of foods is a common formulation process control. Preservatives also can be used to prevent the growth of microorganisms by denaturing protein, inhibiting enzymes, or altering or destroying the cell walls or cell membranes of microorganisms. Some of the most common preservatives are acetic acid, benzoates, natamycin, nisin, propionates, sorbates, and sulfites. FDA lists fresh, refrigerated, RTE deli salads as a food category that can benefit from the use of preservatives. Dehydration/Drying. As one of the oldest methods of food preservation, there are three primary methods used in the U.S.: freeze drying (for various foods), forced-air drying (for solid foods like vegetables and fruit), and spray drying (for liquids and semi-liquids like milk. These are usually considered shelf stable because of their low water activity, but when used, a packaging material should be used that will prevent rehydration of the product under the expected conditions of storage and distribution. (Further information will be forthcoming in Chapter 9.) Recipe Management. This can be used as a process control for a food ingredient (such as a food or color additive or GRAS substance) which can be a chemical hazard if added in excess of a maximum use level. Storage Conditions. Used as a process control for mycotoxins (e.g., molds) that can infect and proliferate on raw agricultural commodities in the field or during storage or transportation due to improper drying or re-wetting of the crop from rain or condensation. The principal process control for prevention of mold growth in storage conditions is the control of moisture, as large-scale storage generally takes place in structures that generally are not well adapted for temperature control. Physical Sorting. Again being a process control for mycotoxins, the mechanical removal of contaminated seeds or kernels is considered to be a practical and effective process control to reduce the mycotoxin content of the bulk raw agricultural commodity. Process Controls for Physical Hazards While FDA intends to devote a full chapter to Preventive Controls for Physical Hazards (Chapter 13), it addresses exclusion strategies as a process control for metals and glass in this chapter. Metal Hazards. Metal-to-metal contact during processing (e.g., fragments breaking off of equipment) can introduce metal fragments into products. This can be controlled with the use of physical separation techniques (such as magnets, sieves, screens, or flotation tanks); electronic or X-ray metal detection devices; and regular inspection of at-risk equipment for signs of damage. Additionally, when calibrating and using equipment, it is important to consider the nature of the food, processing factors, such as ambient humidity or product acidity, and any other factors that could affect the detection/separation of the metal. Glass Hazards. Glass fragments can be introduced into food whenever processing involves the use of glass containers. Normal handling and packaging methods, especially mechanized methods, can result in breakage. While not discussed in this chapter, processors also should address other potential glass hazards (such as overhead light breakage, etc.) through GMPs. X-ray can be a good option to detect both glass and other non-metal foreign objects as well as for metal detection. As you can see from the details discussed above, FDA is going to a lot of trouble to give us all a good idea of what they regard as appropriate preventive controls. Keep in mind that your HACCP plan and CCPs are all likely going to be in your Food Safety Plan. However, as we keep saying at TAG, there is a need to think beyond HACCP and attack this issue more broadly through the lens of risk-based preventive controls. About The Acheson Group (TAG) Led by Former FDA Associate Commissioner for Foods Dr. David Acheson, TAG is a food safety consulting group that provides guidance and expertise worldwide for companies throughout the food supply chain. With in-depth industry knowledge combined with real-world experience, TAG’s team of food safety experts help companies more effectively mitigate risk, improve operational efficiencies, and ensure regulatory and standards compliance. www.AchesonGroup.com
