For questions regarding this draft document contact the Center for Food Safety and Applied Nutrition (CFSAN) at 240-402-2022.

This draft guidance, when finalized, will represent the Food and Drug Administration's (FDA's) current thinking on this topic. It does not create or confer any rights for or on any person and does not operate to bind FDA or the public. You can use an alternative approach if the approach satisfies the requirements of the applicable statutes and regulations.

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Table of Contents

1. Introduction
2. Discussion
   1. Considerations for Evaluating the Effectiveness of Certain Salmonella Control Measures
   2. Recommendations
3. References
   1. FDA Web Site References
   2. References Without Web Site Addresses
   3. Non-FDA Web Site References

I. Introduction

This draft guidance is intended for manufacturers who use a pistachio-derived product as an ingredient in a food product. Pistachio-derived products include roasted in-shell pistachios and shelled pistachios (also called kernels) that are roasted or raw. We are issuing this guidance in light of a recent investigation by FDA and the California Department of Public Health of Salmonella species (Salmonella spp.) contamination in pistachio-derived products (Refs. 1 and 5). The producer issued a voluntary recall involving a substantial quantity of its products. Because the recalled pistachio-derived products were used as ingredients in a variety of foods, this recall affected many products and resulted in additional recalls.

Salmonella can cause serious and sometimes fatal infections in young children, frail or elderly people, and others with weakened immune systems. Healthy persons infected with Salmonella often experience fever, diarrhea (which may be bloody), nausea, vomiting, and abdominal pain. In rare circumstances, infection with Salmonella can result in the organism getting into the blood stream and producing more severe illnesses such as arterial infections (i.e., infected aneurysms), endocarditis, and arthritis.

FDA may take enforcement action, including pursuing product seizure, where food has tested positive for Salmonella species spp. (Refs. 2 and 3). The circumstances under which food is deemed adulterated are set forth in section 402 of the Federal Food, Drug, and Cosmetic Act (FFDCA), and related prohibitions applicable to adulterated food are contained in section 301 (21 U.S.C. 342 & 331). Consequences for violations of the FFDCA include seizure, injunction, and criminal prosecution. (See, e.g., sections 301(a) through (c) and section 303(a) of the FFDCA).

This guidance does not provide recommendations for producers of pistachio-derived products. Importantly, this guidance does not diminish the responsibility of producers of pistachio-derived products to ensure that foods that they produce are not "adulterated" under the FFDCA or otherwise in violation of the law. FDA has contacted producers of pistachio-derived products to remind them that our current good manufacturing practice (CGMP) regulations apply to them (Ref. 4)

FDA's guidance documents, including this guidance, do not establish legally enforceable responsibilities. Instead, guidances describe the Agency's current thinking on a topic and should be viewed only as recommendations, unless specific regulatory or statutory requirements are cited. The use of the word should in Agency guidances means that something is suggested or recommended, but not required. 

II. Discussion

A. Considerations for Evaluating the Effectiveness of Certain Salmonella Control Measures

Salmonella spp. are bacteria that ordinarily are sensitive to heat and high acidity. This sensitivity is often the basis for food processing used to control the presence of the organism. For example, it takes only 3 seconds to achieve a 5-log reduction in Salmonella at 71 °C (equivalent to 160 °F) in fruit juices (Ref. 6).

While considered heat sensitive, Salmonella spp. can become heat resistant in dry food products such as powdered milk (Ref. 7) or in low water activity products such as chocolate syrup and peanut butter (Refs. 8 and 9). The water activity of pistachios is generally low; for example, pistachio nuts may be dried to a water activity of 0.82 for short-term or 0.70 for long-term storage to prevent mold growth and aflatoxin contamination (Ref. 10). The relationship of Salmonella heat resistance to water activity has been well-studied at water activities between 0.99 and 0.85. Generally, Salmonella becomes more heat resistant as the water activity of a food becomes lower (Refs. 11 and 12). For example, it takes less than 5 minutes to achieve a 5-log reduction of Salmonella at 140 °F in a food with a water activity of 0.99 (Ref. 13). However, it takes 50 minutes to achieve the same reduction of Salmonella at 140 °F in a food with a water activity of 0.85 (Ref. 14).

The effectiveness of processing conditions used to reduce Salmonella spp. in a particular food containing a pistachio-derived product as an ingredient may depend on whether, and to what extent, the water activity of the pistachio-derived product changes within the food matrix to which it is added. Any Salmonella in the pistachio-derived product would be expected to become relatively less heat resistant if the ingredient attained a higher water activity within the food matrix, whereas it would not be expected to respond in this manner if the pistachio-derived product retained its initial water activity. Similarly, any Salmonella that might move into a higher water activity portion of the food matrix and rehydrate would be expected to become less heat resistant. Therefore, the heat resistance of Salmonella spp. introduced through a pistachio-derived product, will, upon incorporation into a food matrix, depend upon the nature of the food and the way in which the food is handled during manufacture. For example, Salmonella spp. originally present in a pistachio-derived product, which is added and thoroughly mixed into a food such as a bakery product mix, has the potential to move uniformly in the mix, rehydrate, and become less resistant to heat. However, factors affecting the rehydration, such as the amount of time between preparing the bakery product mix and cooking it, could affect the susceptibility to heat of the Salmonella spp. during the baking process. In addition, knowing that a baked good is heated at an oven temperature such as 375 °F for a fixed time (such as 10 minutes) does not provide information about the temperature actually achieved at the coldest point in the bakery product, the uniformity of the temperature achieved in the bakery product, and the actual duration of time that the bakery product experienced its final temperature.

B. Recommendations

Because procedures used to manufacture finished products containing a pistachio-derived product as an ingredient may or may not adequately reduce² the presence of Salmonella spp., FDA recommends that:

• Manufacturers of foods containing a pistachio-derived product as an ingredient obtain pistachio-derived product only from suppliers with validated processes in place to adequately reduce the presence of Salmonella spp. (e.g., by 5 logs).
• Manufacturers purchasing a pistachio-derived product as an ingredient in a form for which no such validated process is available (e.g., raw shelled pistachios), and manufacturers that have purchased a pistachio-derived product about which questions have been raised concerning the potential presence of Salmonella spp. in a particular lot or lots, ensure that their own manufacturing process would adequately reduce the presence of Salmonella spp. (e.g., by 5 logs) (based upon a combination of time and temperature, or other means). In evaluating the ability of their manufacturing processes to reduce the presence of Salmonella spp. in the finished product, such manufacturers should take the following considerations into account:
  • Based on the available data and information, the processing conditions appropriate to adequately reduce Salmonella spp. in a particular food product vary depending on the specific characteristics of the food product.
  • Determining the processing conditions appropriate to adequately reduce Salmonella spp. in a particular food product involves considerable expertise in both food microbiology and the physics of heat transfer.
  • The most reliable way to determine whether a manufacturing process would reduce the presence of Salmonella spp. in a food product containing a pistachio-derived product as an ingredient is to conduct a scientific study to determine the death rate of Salmonella spp. in the product using microbiological challenge studies, taking into account properties of the food.
  • A history of negative microbiological tests for Salmonella spp. in the finished product, while useful in a verification program for a process, is not sufficient, by itself, to determine the adequacy of a process in reducing the presence of Salmonella.

FDA is aware that the Grocery Manufacturers Association (GMA), collaborating with other food industry organizations in a Salmonella Control Task Force, has very recently published an industry guidance document reviewing and synthesizing information about industry programs in place to control Salmonella spp. and help ensure the safety of low-moisture food products (Refs. 15 and 16). Manufacturers that use a pistachio-derived product as an ingredient in a food product may find GMA's document useful. Please be aware that FDA is not responsible for the content of GMA's document, which FDA did not create and has not verified.

FDA is continuing to work closely with the pistachio industry to help it understand the risk of Salmonella and its regulatory obligations under the laws administered by the agency.

III. References

A. FDA Web Site References

The following references were available on FDA's Web site as of June 9, 2009. We also have placed these references on display in the Division of Dockets Management, Food and Drug Administration, 5630 Fishers Lane, rm. 1061, Rockville, MD 20852. You may see them at that location between 9 a.m. and 4 p.m., Monday through Friday.

1. FDA. 2009. Safety. Update on Pistachio Product Recall. As of the date of this guidance, this Web site is an active site that adds information over time to provide the most current information about the recall. Persons who access this Web site after June 9, 2009, may find different information than the information we placed in the Division of Dockets Management.
2. FDA. 2005. Compliance Policy Guide Sec. 527.300 Pathogens in Dairy Products (7106.08).
3. FDA. 1995. Compliance Policy Guide Sec. 555.300 Foods, Except Dairy Products - Adulteration with Salmonella (7120.20).
4. FDA. 2009. April 3, 2009 FDA Letter to Processors About Current GMPs.

B. References Without Web Site Addresses

We have placed the following references on display in the Division of Dockets Management, Food and Drug Administration, 5630 Fishers Lane, rm. 1061, Rockville, MD 20852. You may see them at that location between 9 a.m. and 4 p.m., Monday through Friday.

5.  FDA. 2009. Pistachio Product Recalls: Salmonella. Updated: April 16, 2009.
6.  Mazzotta, AS. 2001. Thermal Inactivation of Stationary-Phase and Acid-Adapted Escherichia coli O157:H7, Salmonella, and Listeria monocytogenes in Fruit Juices. Journal of Food Protection 64 (3): 315-320.
7.  Dega, C. A., J. M. Goepfert, and C. H. Amundson. 1972. Heat Resistance of Salmonellae in Concentrated Milk. Applied Microbiology 23:415-420.
8.  Goepfert JM, Biggie, and RA. 1968. Heat Resistance of Salmonella Typhimurium and Salmonella seftenberg 775W in Milk Chocolate. Applied Microbiology 16: 1939-1940.
9.  Shachar D, and Yaron S. 2006. Heat Tolerance of Salmonella enterica Serovars Agona, Enteritidis, and Typhimurium in Peanut Butter. Journal of Food Protection 11: 2687-2691.
10.  Aktas, T and Polat, R. 2007. Changes In The Drying Characteristics And Water Activity Values Of Selected Pistachio Cultivars During Hot Air Drying. Journal of Food Process Engineering 30:607-624.
11.  Corry J. 1976. The Safety of Intermediate Moisture Foods with Respect to Salmonella. In Intermediate Moisture Foods, eds R Davies, G Birch and K Parker, 215-238. London: Applied Science Publishers Ltd.
12.  D'Aoust J-Y. 1989. Salmonella. In Foodborne Bacterial Pathogens, ed M Doyle, 327-445. New York: Marcel Dekker.
13.  Baird-Parker AC, Boothroyd M, and Jones E. 1970. The Effect of Water Activity on the Heat Resistance of Heat Sensitive and Heat Resistant Strains of Salmonellae. Journal of Applied Bacteriology 33: 515-522.
14.  Gibson B. 1973. The Effect of High Sugar Concentrations on the Heat Resistance of Vegetative Microorganisms. Journal of Applied Bacteriology 36: 365-376.

C. Non-FDA Web Site References

The following references were available on the Internet on the date identified in the reference list. As of April 16, 2009, FDA had verified the Web site addresses it makes available as a hyperlink from the Internet copy of this guidance, but FDA is not responsible for any subsequent changes to the Web sites after posting this guidance on its Web site. We have placed these references on display in the Division of Dockets Management, Food and Drug Administration, 5630 Fishers Lane, rm. 1061, Rockville, MD 20852. You may see them at that location between 9 a.m. and 4 p.m., Monday through Friday.

15.  Grocery Manufacturers Association. 2009. Control Of Salmonella In Low-Moisture Foods. (available in PDF) Accessed on April 16, 2009.
16.  Grocery Manufacturers Association. 2009. Annex to Control Of Salmonella In Low-Moisture Foods. (available in PDF) Accessed on April 16, 2009.

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1. This guidance has been prepared by the Division of Plant and Dairy Food Safety in the Center for Food Safety and Applied Nutrition at the U.S. Food and Drug Administration.

2. In this document, we use the phrase "adequately reduce" to mean capable of reducing the presence of Salmonella to an extent sufficient to prevent illness. The extent of reduction sufficient to prevent illness usually is determined by the estimated extent to which Salmonella spp. may be present in the food combined with a safety factor to account for uncertainty in that estimate. For example, if it is estimated that there would be no more than 1000 (i.e., 3 logs) Salmonella organisms in the food, and a safety factor of 100 (i.e., 2 logs) is employed, a process adequate to reduce Salmonella spp. would be a process capable of reducing Salmonella spp. by 5 logs.

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Related Information

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