It’s been one year since perhaps the largest recall in United States history due to Salmonella contamination. For months, headlines were teeming with news of affected peanut products and the scandal behind the outbreak. In the end, more than 400 products were recalled and consumer illnesses were reported in nearly every state across the country.
Unfortunately, this event is not a freak accident. It seems there is at least one large Salmonella contamination incident every year that causes stores to pull recalled products off their shelves and consumers to raid their pantries for affected food.
There are about 40,000 reported cases of Salmonellosis, or Salmonella poisoning, in the United States each year and more than 500 people die from complications from the illness. Since many mild cases are not reported, the Centers for Disease Control and Prevention estimates that the actual number of affected people may be closer to two million.
So, what exactly is Salmonella and what can the food industry do to help prevent future incidents from occurring?
THE FACTS. There are more than 2,300 types of Salmonella bacteria; however the two most common types, Salmonella enteritidis and Salmonella typhimurium, account for half of all human infections. Any raw animal products, such as meat, poultry, dairy products, eggs, and seafood, as well as some produce may carry Salmonella bacteria. However, Salmonella outbreaks have been increasingly linked to low-moisture food products.
These microscopic organisms are usually transmitted by eating foods contaminated with animal feces, causing diarrhea, fever and abdominal cramps. In most cases, the illness lasts no longer than a week and does not require medical intervention. However, there are severe cases where the patient needs to be hospitalized and treated with antibiotics to prevent the infection from spreading from the intestines to the blood stream and other body sites. Salmonella infections in infants, children, pregnant women, and older adults can be especially dangerous because these people are more prone to complications due to their weakened immune systems.
PREVENTION. The only way to reduce Salmonella contamination is to adopt food safety practices as a way of life throughout the food supply chain. A comprehensive farm-to-table approach to food safety is needed to protect food from the time it is picked from the field to the time it reaches the consumer’s mouth. All who are involved in the process must be aware of the effects of Salmonella and be committed to doing their part to prevent contamination from occurring.
The key to preventing Salmonella contamination is to stop the bacteria from growing, to protect against cross-contamination, and to destroy the bacteria. There are several important Prerequisite Programs that food companies need to have in place to make sure these prevention steps are carried out.
PERSONAL PRACTICES. Food company employees can be a source of contamination since they are in constant contact with food products and product contact surfaces. Poor personal hygiene is a leading reason for microbiologically contaminated products. Every company should have a Personnel Practices Program in place that outlines basic measures that must be taken to help prevent contamination. These include:
Handwashing. Outbreaks of illnesses are often associated with persons in close contact with one another who contaminate their hands by touching common surfaces, such as doorknobs, and then touch their mouth, nose or eyes. The same concept applies in the food industry, but rather than personal infection, the concern is product contamination. One of the most important activities a food handler can perform is hand washing and sanitizing.
Although undoubtedly employees have been washing their hands since they were very young, adequate techniques and frequencies may not yet be routine. It is important that both of these factors are addressed in the hand washing policy and training. Hand washing must include warm water and soap. Personnel should scrub their hands for 20-30 seconds. Not only is the time of scrubbing important, but focusing on cracks and crevices, such as around knuckles and fingernail beds, is also crucial.
Hand sanitizing can be accomplished by using a soap containing sanitizer or by applying a sanitizer after washing and drying the hands. Many facilities have installed waterless sanitizers at workstations where sinks may not be practical. This allows for a final sanitizing of hands after washing and prior to handling product or product contact surfaces.
The hand-washing policy must also address when hands are to be washed. Typical policies will require that hands be washed after using the restroom, after eating, after smoking, and before handling product. Basically, hands should be washed any time they become unsanitary or after any absence from the workstation. Hand washing also may be required when moving from one part of an operation to another, such as from raw to finished product or from an allergen area to a non-allergen area.
Uniforms/Outer Garments. The type of outer garment to be worn depends on many factors. Facilities that are considered microbiologically sensitive, such as meat, dairy, or cut produce operations, may require employees to change into uniforms, including shoes, at the plant.
A good uniform policy addresses all personnel, not just production personnel. Special considerations may be required for maintenance or laboratory personnel. For example, if microbiological testing is conducted on-site, the garment worn by the microbiologist should not be worn out of the testing lab, particularly not into processing areas.
MICROBIAL CONTROL PROGRAM. The Microbial Control Program identifies quality and food safety issues and implements steps to proactively control microorganisms. The Microbial Control Program also addresses concerns with conducting on-site microbial testing and assurances that the test methods and results are valid.
The goal of the Microbial Control Program is to know the types of bacteria associated with the products, the process, and finished product requirements and to verify that effective controls are in place to prevent quality and food safety issues in the marketplace.
The first step in establishing a Microbial Control Program is to conduct a risk assessment to identify the types of microorganisms that will be a concern for the plant. The assessment is based on raw materials, processing environment, and finished product testing requirements.
Once the risk assessment is completed and the organisms of concern have been identified for their relative sources (raw material or finished goods), a sampling program must be established. Sampling must be done in a way that does not compromise product or the sample. For example, the sampling tools, such as a scoop, must not introduce contaminants (microorganisms, allergens, etc.) to the product or sample. Personnel responsible for sampling must be trained to handle the sampling materials so they do not contaminate the sample. Sterile utensils should be used for product sampling so that the sample is not contaminated.
The check sample component of the Microbial Control Program is designed to identify testing methods that are not in agreement with the standard. It is based on sharing a sample among multiple technicians. Each technician performs the analysis and results are compared. While the results are not expected to be exact, they are expected to fall within a reasonable range. Results for multiple tests should also be evaluated. For example, if a particular technician always reports the highest or lowest result, even if reasonably close to the others, this may be an indication of a variance in test method and should be investigated.
SANITATION. Maintaining a sanitary environment is essential to the success of any food company. The Sanitation Program is designed to maintain the sanitary condition of food contact surfaces and the facility environment. An effective Sanitation Program includes the identification of required cleaning tasks and frequencies, effective cleaning methods and required materials, and training. Cleaning of the equipment and the environment will help to protect product from Salmonella contamination.
Written cleaning procedures are needed to ensure that cleaning is consistent from person to person. A well-written procedure will provide enough detail for someone to complete the task by strictly following the instructions.
EQUIPMENT & UTENSILS. Equipment and tools can be potential sources of Salmonella contamination if not properly sanitized. Seams on food-contact surfaces need to be smoothly bonded or maintained because rough surfaces support product buildup and bacterial growth. They are also difficult to clean.
Equipment and utensils that are approved for food contact should be clearly identified to help prevent unwanted contamination. Food contact equipment and utensils should be segregated so that contamination does not occur during storage. Only clean repair parts and equipment should be placed in the storage area.
Process control devices are needed to monitor time, temperature, moisture levels, pressures, and flow rates of food products in various process phases. Sensitive food requiring either hot or cold processes or storage conditions to prevent food safety issues need to be monitored closely. This can be done using continuous recording devices or systems that must be manually checked at pre-determined intervals. Either way, these critical devices must be routinely calibrated against a standard to make sure they are accurate. Many facilities prefer automated systems with alarms that notify when temperatures exceed the limits imposed. If repairs are needed to restore the system to the established limits, they must be a top priority.
TEMPERATURE CONTROL. Temperature control is one of the best ways to control the growth of Salmonella. Storing, transporting and cooking products at appropriate temperatures to prevent the growth of Salmonella are essential. An effective Temperature Control Program identifies temperature sensitive materials, establishes time and temperature control parameters, monitors temperature, and takes corrective action for temperature deviations outside the control limits. Temperature control may include cooking, refrigeration, freezing, cooling, and tempering (thawing).
Most microorganisms have ideal growth between the temperatures of 40oF and 140oF. This is referred to as the temperature danger zone. While growth will occur outside these temperatures, it is significantly slowed.
In the United States, the cGMPs address temperature control in the Code of Federal Regulations as follows:
• Raw materials, ingredients, and rework are held at a specific temperature and relative humidity to prevent the food from becoming adulterated by undesirable bacteria growth.
• Frozen raw materials and other ingredients are kept frozen. If thawing is required prior to use, it is done in a way that prevents the raw materials and other ingredients from becoming adulterated.
• Each freezer and cold storage compartment used to store, hold, or transport food capable of supporting growth of microorganisms is fitted with devices that confirm that temperature requirements have been met. Examples include indicating thermometers, time/temperature-measuring devices, alarm systems, or documented manual checks to confirm that time/temperature requirements have been met during handling, storage, or delivery of food products.
• Instruments and controls used for measuring, regulating, or recording temperatures that control or prevent the growth of undesirable microorganisms in food are accurate and adequately maintained and sufficient in number for the product and area to be controlled. The devices and instruments used to monitor temperature should be under a calibration program to ensure that the data being recorded is accurate.
• During the modernization of the GMPs, it was determined that further discussions were needed to identify appropriate revisions to the temperature control requirements as our knowledge about food microbiology continues to improve. Government agencies are developing more prescriptive guidance to the entire food chain to ensure the food supply is as safe as possible.
CONCLUSION. In March 2009, the Grocery Manufacturers Association published an extensive study on the Control of Salmonella in Low-Moisture Foods. In a nutshell, the paper outlines seven elements that food facilities should apply to minimize the risk of Salmonella contamination. These include:
- Prevent the introduction or spread of Salmonella in the facility.
- Enhance the stringency of hygiene practices and controls in the Primary Salmonella Control Area.
- Apply hygienic design principles to building and equipment design.
- Prevent or minimize growth of Salmonella within the facility.
- Establish a raw materials/ingredients control program.
- Validate control measures to inactivate Salmonella.
- Establish procedures for verification of Salmonella controls and corrective actions.
With well-developed Prerequisite Programs and employees who understand their roles in preventing food product contamination, the spread of Salmonella bacteria will be greatly reduced. AIB
The author is Publications Coordinator for AIB International.