Food Protection Trends - July 2009 - 447

Dr. Donald Zink, Senior Science Advisor for FDA’s Center for Food Safety and Applied Nutrition, offered a talk titled, “Salmonella in Peanut Products: Understanding the Risk and Controlling the Process – The FDA Perspective.” Dr. Zink provided an overview of FDA activities related to outbreaks in general and the PCA salmonellosis outbreak specifically. In spite of the difficulties encountered due to the “ingredient nature” of peanut butter, the investigation was organized and orderly due to the use of an effective incident command system at FDA. Ultimately, thousands of products from hundreds of companies have been recalled. He noted that many companies deemed recalls easier than attempting to validate their processes to maintain product on the market. Validation obstacles are due to the significant heat resistance of salmonellae at low water activity and existence of limited data on this topic. One issue of interest from the investigation was the difficulty in notifying vending companies of recalls. Dr. Zink noted that some wholesale club stores are capable and willing to provide recall information to customers, such as vending companies, who purchase recalled products. Dr. Zink mentioned that Salmonella testing can be product and strain specific thereby creating difficulties in detecting the organism in foods. Salmonellosis outbreaks and illnesses from foods, other than eggs, have not declined in recent years. Observations from investigations of outbreaks include notable items such as: • Failure to appreciate the importance of Salmonella control in certain high risk foods • Too much reliance on finished product testing • Poor implementation of GMPs • Ineffective implementation of appropriate system monitoring • Inadequate qualification of critical ingredient suppliers • Inadequate cleaning, sanitation and pest control • Inadequate response to Salmonella findings in finished products and the environment Peanut product manufacturers need to learn more about control of Salmonella including process validation, limitations of testing, and environmental monitoring. Dr. Zink noted that salmonellae in the manufacturing environment will eventually find its way into the product. Exceptional GMPs and SSOPs are necessary to reduce likelihood of pathogen contamination. A recent FDA analysis of a food processing facility found seven serotypes of salmonellae whereas the company’s own monitoring program had found nothing. This illustrates that training on testing methodology and knowing where to look for Salmonella is needed. Dr. Zink concluded his remarks by stating that companies need to plan on how to respond if Salmonella is found in the product or immediate environment. Production should be terminated, the pathogen harborage found and eliminated, and status of lots produced since last cleanup determined. In a presentation titled, “Impact of Processing Environments on Control of Salmonella in Low Moisture Food Plants,” manager of the ConAgra peanut plant in Sylvester, GA, Mr. Earl Ehret, provided an account on measures needed to renovate and reopen the facility after the 2006–2007 salmonellosis outbreak from peanut butter. He provided a brief timeline of events beginning with the voluntary recall announced in February 2007, through April when the likely causes of the contamination were announced and August when the facility was reopened and shipped product. It is likely that contamination events occurred due to the presence of Salmonella in the processing environment, possibly from raw peanuts and peanut dust, combined with moisture from roof leaks. ConAgra invested $33 million in facility renovations including new roof, walls and sealed floors. Physical separation of raw peanuts and finished product was built into the new facility with new walls and coded door locks. Separate clean-out-of-place areas for raw and finished processes were built along with a new HVAC system to create appropriate positive or negative air pressures and manage peanut dust. Equipment and personnel traffic control with color coding was implemented to prevent crosscontamination. Although water is used in the processing portion of the plant, Mr. Ehret indicated that all other areas are cleaned manually using sanitizer and hand wiping. Other changes include training employees in SQF, surprise corporate audits, at least 50 routine environmental tests per week to monitor critical areas, extensive contractor training in food safety, and increased frequency of finished product testing with a five day hold-andrelease. His final advice is that food safety must be thoroughly integrated into all aspects of your business rather than a separate part of the business. Dr. Larry Beuchat, Distinguished Research Professor from the University of Georgia provided an overview titled, “Behavior of Salmonella in Foods with Low Water Activity.” General characteristics of the organism, the disease state, survival in low water activity products, heat tolerance and other microbiological concerns were discussed. Dr. Beuchat mentioned outbreaks from other products with low water activity and from other peanut products. These include paprika on potato chips, breakfast cereals, soft cheeses, infant formula, ice cream, pastry, cooked ham, peanut flavored snacks, peanut butter, peanut sauce and inshell peanuts. Salmonellae are very hardy and can grow at temperatures as low as 2°C, water activity as low as 0.93, and pH between 3.9 and 9.5. This pathogen can adapt to extreme environmental conditions such as desiccation, pH and temperature stress. Survival is enhanced at refrigeration and freezing temperatures as well as at low water activity. Studies have shown survival of salmonellae in milk chocolate for >9 months, in almonds for >550 days, and in peanut butter and spreads for more than 24 weeks. Factors affecting heat tolerance include prior growth conditions, composition of foods, stationary vs. log phase cells, and growth in an environment with limited nutrients. Tolerance of certain salmonellae increases if cells are grown at elevated temperatures prior to application of heat stress. Studies indicate that log reductions between 1.8 and 3.0 occur after various Salmonella serotypes are exposed to 20 minutes at 70, 80 and 90°C in peanut butter. In addition to Salmonella, other pathogens have been shown to survive in peanut products. Clostridium botulinum can grow in peanut spread at high water activities. Listeria monocytogenes survives in peanut butter and chocolate peanut spread for 16 to 24 weeks at 20°C. In summary, Dr. Beuchat indicated that Salmonella remains viable in peanut products for extended time periods and survival is enhanced in high fat and low water activity foods. JULY 2009 | FOOD PROTECTION TRENDS 447

Food Protection Trends - July 2009

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