Tag Archives: salmonella

Scanning electron micrograph shows a colony of Salmonella typhimurium bacteria. Photo courtesy of CDC, Janice Haney Carr

State of Salmonella: Technology and Industry Trying to Reduce Rates

By Maria Fontanazza
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Scanning electron micrograph shows a colony of Salmonella typhimurium bacteria. Photo courtesy of CDC, Janice Haney Carr

By 2020, the CDC has targeted a reduction in Salmonella cases at 11.4 per 100,000 people (last year’s rate was 15.4 per 100,000). Considering that the number of cases has not declined in the past 10+ years, regulators and industry will need to work together more closely on utilizing methods and technologies that provide effective pathogen detection.

Scanning electron micrograph shows a colony of Salmonella typhimurium bacteria. Photo courtesy of CDC, Janice Haney Carr
Scanning electron micrograph shows a colony of Salmonella typhimurium bacteria. Photo courtesy of CDC, Janice Haney Carr

It is a well-known fact within the food safety industry that Salmonella is the second most common foodborne illness in the United States, and the bacteria comes in first place in the category of foodborne illnesses that lead to hospitalization or death.  Unfortunately, there has been no change in the number of confirmed infections between the 2006-2008 period and last year, according to the CDC’s Foodborne Diseases Active Surveillance Network (FoodNet) 2014 Food Safety Progress Report. 

“The major threat Salmonella poses is that its public health impact has remained largely unchanged despite many years of regulatory oversight and technological improvements,” says Evan Chaney, Ph.D., senior manager, scientific affairs at Roka Bioscience. “Reducing the existing public health burden of Salmonella is a complex challenge that will require new and innovative thought, research, and technological developments or processes.”

Each year Salmonella makes its way into the food supply through a variety of sources, sickening more than 1 million people in the United States and costing the country nearly $3.7 billion, according to the USDA. Although it is most commonly found in contaminated animal-derived products, the level of serious outbreaks over the past few years is cause for concern, as the bacteria have appeared in processed foods such as peanut butter and fresh produce, including cucumbers, cantaloupes, alfalfa sprouts and jalapeno peppers.

USDA’s Food Safety and Inspection Service (FSIS) proposed federal measures in January to lower the rate of Salmonella in poultry, including a pathogen reduction performance standard for chicken parts, and ground chicken and turkey. FSIS began the sample project for raw chicken parts in March (only for firms that produce more than 1,000 lbs of chicken parts daily) and a verification testing program for poultry carcass inspection, using a moving window of sampling results, in May (view the full Federal Register notice).

Technologies Taking Down Salmonella

Providing rapid pathogen detection for Salmonella in less than 24 hours has been a priority for industry. Companies want to both prevent contaminated foods from entering the market as well as ensure that products can be quickly tested so that they are not sitting in a warehouse for days awaiting results. With this focus comes a need to provide testing in the processing environment.

“I think we will see an increase in testing related to the Food Safety Modernization Act, and there’s a trend toward environmental testing as opposed to finished product testing,” says Meredith Sutzko, Product Manager, Food Pathogens of Romer Labs North America. “Processors are looking to identify contamination very early in the process. To do that, they need simple and cost-effective methods, especially ones that will deliver a fast time-to-result and can be used at the production facility so they don’t have to wait to obtain test results.”

From enzyme immunoassays (EIA) and enzyme-linked immunosorbent assays (ELISA) to PCR assays, there are a large variety of established testing and identification technologies on the market. However, in taking a different approach to lowering the risk of Salmonella from entering the market, companies can employ limits testing as an additional tool to verify process control within a production shift. Salmonella limits testing is a semi-quantitative method that provides a “positive” or “no-go” result based on initial contamination levels of a sample, and does so within a day.

Limits testing provides a semi-quantitative approach to lowering Salmonella levels. Image courtesy of Roka Bioscience
Limits testing provides a semi-quantitative approach to lowering Salmonella levels.
Image courtesy of Roka Bioscience

“A key difference in this testing approach is the utilization of a pathogen test as a means of process control or intervention, an example of a tool utilized in a new manner,” says Chaney, adding that in most cases, pathogen testing is conducted on finished product or on lots of product in concordance with COA requirements. While it is important to provide results that indicate both qualitative (presence or absence) and quantitative (estimates concentration), having insight into actual concentration levels provides another layer of risk mitigation. “We need tools to help us understand what Salmonella loads are in the system in a rapid manner so that action can be taken. This is the purpose of limits testing.”

As a case example of limits testing being used in the field, Cargill asked Roka Bioscience to develop a limits-based approach for testing its ground turkey for Salmonella. Roka was required to provide Salmonella detection levels at about 1 CFU/g in a 375 g sample size of ground meat in less than eight hours (total time to result). Roka successfully developed the limits application, and Cargill now uses the tool to make product disposition decisions prior to shipping its ground turkey. Roka is also looking at other areas in which limits testing can be used, from the pre-harvest to live production environments.

Calling on industry to push harder to innovate in foodborne pathogen detection, FDA announced its 2014 Food Safety Challenge last fall. The agency is offering a hefty prize—$500,00—to the team that can develop a technique or technology that creates “significant improvements” in the speed at which FDA can detect Salmonella in fresh, minimally processed produce. The finalists, announced last month, have received $20,000 to further develop their concepts and are being mentored by FDA in food safety and pathogen testing.

Technology contenders for the challenge include:

  • A handheld magnetoelastic biosensor and surface-scanning detector that can be passed over food to detect surface contamination. The portable device can be used both in a process facility as well as remote locations in which produce is being harvested and delivers results in minutes, according to the team’s leader, Bryan Chin, director of the Auburn University Detection and Food Safety Center.
  • Patented high-throughput technology for capturing Salmonella in large sample volumes. Developed by UC Davis School of Veterinary Medicine and scientists from Mars, Inc., the test uses fluidized bed technology to detect bacteria in less than four hours and presents potential for larger food processors. View the UC Davis video
  • DNA aptamer-magnetic bead sandwich assay, for use with a handheld florescence reader. Developers of the assay are from Pronucleotein, Inc. and Xgenex
  • Method for concentrating salmonella to detectable levels using automated microfiltration, developed by Purdue University.
  • Portable system for multiplexed detection of foodborne pathogens in microfluidic biochips through isothermal DNA amplification and electrical detection, developed by University of Illinois and Purdue University.

On July 7, FDA is holding a Demo Day at the Center for Food Safety and Applied Nutrition in Maryland where the finalists will present their refined concepts to judges from the FDA, USDA, and CDC, and a live audience. The winner of the Food Safety Challenge will also be announced sometime next month.

Risk Assessment in Pathogen Testing Methods

By Food Safety Tech Staff
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A Certificate of Analysis (COA) provides a level of confidence in the quality and purity of its product. Companies should take this document a step further and assess what the results mean. Using Failure Modes and Effects Analysis (FMEA) can help a company identify, quantify and assess risks associated with pathogen detection methods, giving them the background information they need to trust the results. FMEA can help companies understand the differences between testing methods by individually identifying the risks associated with each method on its own. Maureen Harte, President and CEO at HartePro Consulting, and Lean Six Sigma Master Black Belt, talks about the challenges a company faces when assessing results on a Certificate of Analysis and the role of FMEA.

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Recent recalls: Glass in Baby Food, Staphylococcal Enterotoxin Contaminated Pork, Salmonella in Whole Foods Macadamia Nuts

By Food Safety Tech Staff
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The latest recalls are affecting Beech-Nut Nutrition, B & R Meat Processing, and Whole Foods Market.

Whole Foods Market recalls packaged raw macadamia nuts due to possible salmonella

Whole Foods Market voluntarily recalls packaged raw macadamia nuts due to possible Salmonella contamination. Recalled items were sold in AR, AZ, CA, CO, HI, KS, LA, NM, NV, OK, TX, and UT Whole Foods Market Stores. No illnesses have been reported to-date. Based upon routine testing conducted by an FDA-contracted laboratory, it was determined that the raw macadamia nuts tested positive for Salmonella.

Beech-Nut Nutrition recalls Sweet Potato & Chicken Baby Food Product due to possible glass contamination

Beech-Nut Nutrition recalls approximately 1,920 pounds of baby food products that may be contaminated with small pieces of glass… The baby food product was produced on December 12, 2014: 4-oz. glass jars containing “Stage 2 Beech-Nut CLASSICS sweet potato & chicken. The problem was discovered after the firm received a complaint from a consumer who found a small piece of glass in the product. The company has received a report of an oral injury associated with consumption of these products. FSIS has received no additional reports of injury or illness from consumption of these products.

Beech-Nut responds: “At Beech-Nut, we strive to make baby food with the best ingredients nature has to offer – freshly prepared and packaged in clean, safe and environmentally-friendly packaging. So, when any product of ours falls short of those standards, we take swift action to correct it.”

B & R Meat Processing recalls 2000+ pounds of pork due to possible processing deviation and staphylococcal enterotoxin contamination

The cured and uncured pork items were produced on various dates between August 7, 2014 and April 1, 2015… The problem was discovered when an FSIS inspector was conducting a Food Safety Assessment and observed a processing deviation.

Latest posted recalls from FDA

115 Sickened: Multistate Outbreak of Salmonella Enteritidis Infections Linked to Bean Sprouts

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So far, 61 outbreaks have been associated with raw sprouts, sickening at least 11,179.

The U.S. Centers for Disease Control reports this outbreak appears to be over.

barfblog-raw-sprouts-Aug-2014A total of 115 people infected with the outbreak strains of Salmonella Enteritidis were reported from 12 states. Twenty-five percent of ill persons were hospitalized. No deaths were reported.

Collaborative investigation efforts of state, local, and federal public health and regulatory agencies indicated that bean sprouts produced by Wonton Foods, Inc. were the likely source of this outbreak.

In interviews, 61 (72 percent) of 85 ill persons reported eating bean sprouts or menu items containing bean sprouts in the week before becoming ill.

In November 2014, Wonton Foods Inc. agreed to destroy any remaining products while they conducted a thorough cleaning and sanitization and implemented other Salmonella control measures at their firm. The firm resumed shipment of bean sprouts on November 29, 2014.

Contaminated bean sprouts produced by Wonton Foods, Inc. are likely no longer available for purchase or consumption given the maximum 12-day shelf life of mung bean sprouts.

Although this outbreak appears to be over, sprouts are a known source of foodborne illness. CDC recommends that consumers, restaurants, and other retailers always follow food safety practices to avoid illness from eating sprouts.

Be aware that children, older adults, pregnant women, and persons with weakened immune systems should avoid eating raw sprouts of any kind (including alfalfa, clover, radish, and mung bean sprouts).

We count 61 outbreaks associated with raw sprouts, sickening at least 11,179.

Salmonella – Most Expensive Pathogen

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The top 15 pathogens, which includes Salmonella, Listeria monocytogenes, Campylobacter and E. coli O157:H7, make up 95 percent of illnesses and deaths from food in the U.S.

Salmonella ranks first among the top 15 most costly foodborne illnesses, raking up around $3.7 billion every year in medical costs for Americans.

According to the latest estimates from USDA’s Economic Research Service, the top 15 pathogens, which also include Listeria monocytogenes (ranked third), Campylobacter (ranked 5) and E. coli O157:H7 (ranked 9), make up 95 percent of illnesses and deaths from food in the U.S.

Salmonella’s cost is $3.7 billion, with 1,027,561 total cases, 19,336 hospitalizations and 378 deaths.

Listeria monocytogenes’s cost is $2.8 billion, with 1,591 cases, 1,173 hospitalizations and 306 deaths.

Campylobacter’s is $1.9 billion, with 845,024 cases, 8,463 hospitalizations and 76 deaths.

E. coli O157’s is $271 million, with 63,153 cases, 2,138 hospitalizations and 30 deaths.

Deaths tend to account for the bulk of the total costs. Death associated with salmonella, for example, cost nearly $3.3 billion, or almost 90 percent, of its $3.7 billion cost.

Click here to see more details.

Thomas R. Weschler, Founder and President, Strategic Consulting, Inc (SCI)

High False Positive Rates for Pathogen Food Safety Testing

By Thomas R. Weschler
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Thomas R. Weschler, Founder and President, Strategic Consulting, Inc (SCI)

This article looks at proficiency testing (PT) for pathogen analysis, and the recent finding by the the American Proficiency Institute (API) of a 6.6 percent false-negative rate on food safety PT samples (14-year average for the 1999-2012 period).

While at IAFP this year, I met with Heather Jordan, who directs food PT programs at API. The proficiency testing programs are used at many food labs in conjunction with lab accreditation programs. Proficiency testing is done at food plant labs (FPLs) and corporate labs, as well as at food contract testing labs (FCLs) as a way to demonstrate quality results in their food micro and chemistry testing.

More proficiency testing but less proficiency?

In fact, the use of PTs is increasing in food labs, which is probably tied in part to the push for lab accreditation by FSMA and non-government groups like GFSI. Yet it seems to me that the current use of PTs doesn’t go far enough to enable an FPL or FCL to demonstrate overall laboratory competency, and gain or maintain accreditation (ISO 17025).

In most labs, PTs are done just a few times a year. And really, they test the competency of the lab technician and protocols used in analyzing the PT samples. They are not a holistic measure of the lab and its ability to consistently generate quality results on every test run by every operator in the lab.

In a previous life I ran a group of environmental testing labs, which also are required to run PT samples during the year. From this experience, I know that lab personnel are aware that PTs are in-house: The sample-receiving group logs them in, and then alerts management. As a result, the best operators usually are assigned to run the PTs. This kid-glove treatment is not representative of day-to-day practices and processes. If we really want to validate and accredit the proficiency of an entire lab, shouldn’t every operator be tested on all protocols in use?

Plus, if labs know when they are running PT samples, and likely have their best operators running them, shouldn’t there be few, if any, false-negative or false-positive results? Surprisingly, that’s not what the API research found…

API study: Performance accuracy for food pathogens remains problematic

In a retrospective study, “Pathogen Detection in Food Microbiology Laboratories: An Analysis of Proficiency Test Performance,” API analyzed the results from 39,500 food proficiency tests conducted between 1999 and 2012 to see how U.S. labs are doing in detecting or ruling out contamination of four common food pathogens.

Over the 14-year period, “False negative results ranged from 3.3 percent to 14.0 percent for E. coli O157:H7; 1.9 percent to 10.6 percent for Salmonella spp; 3.4 percent to 11.0 percent for L. monocytogenes; and 0 percent to 19.8 percent for Campylobacter spp.” Most concerning is that while both false positive and false negative rates were down in the last year of the study, the cumulative false negative rate for the 14-year period was 6.6 percent.

As we know, false positive results (in which a sample that does not contain pathogens is incorrectly shown as positive) are a nuisance. But false negative test results—which fail to detect true pathogenic organisms in the sample—are not unacceptable.

Tom-Weschler-False-Negatives-Sep-2014

The cumulative average false positive rate was 3.1 percent, less than half of the false negative rate for the same period.

The objective of the study—and, I would think, of proficiency testing in general—is to demonstrate improvement in lab performance year over year. The results of the API report concluded to the contrary, however: “Performance accuracy for food pathogens remains problematic with the recent cumulative trend showing a slight decrease for false positive and false negative results.”

Clearly if false negatives happen in proficiency programs, they happen in the course of regular testing at food labs. I’m told that many FCLs and FPLs rely on other parts of their QA systems to make sure testing is being conducted properly. Even so, the documentation of ongoing and unacceptably high false negative rates in PT testing is a big concern for everyone. It also points to a number of follow-on questions:

  • Would the false negative and false positive results be even higher if every technician, rather than the best operator, performed the analysis?
  • PT samples are created in only a couple of sample matrices. Would results be even worse if performed on the myriad of sample matrices present in the food industry?
  • What are the performance results among all of the pathogen methods available? Are some methods better than others when measured in real world conditions? Do the more complex protocols of some pathogen diagnostic systems result in poorer PT performance results?
  • Would PT results and, even more important, lab proficiency improve if the frequency of PTs increased, and were required of every technician involved with real food samples?
  • How can proficiency testing be used to isolate problem areas, whether in the pathogen diagnostic method or the competency of lab operators and processes?
  • And finally, is the performance data different between food contract labs and food plant labs? And are all FCLs are equal, or are some more able to deliver quality results?
Bob Savage, President and Founder of the HACCP Consulting Group

FSQA: Creating HACCP Excellence

By Michael Biros
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Bob Savage, President and Founder of the HACCP Consulting Group

For a successful Food Safety and Quality Assurance program, there must be management commitment and measurable expectations set. Senior management has to be committed to the program. They are the foundation for everything in food safety. They have to provide resources to develop and implement the plans across different departments as well as provide for training and encourage communication, advises Robert A. Savage, President and Founder of The HACCP Consulting Group.

Sharing some lessons learned from decades of HACCP implementation experience, Savage spoke at a recent webinar on FSQA: Creating HACCP Excellence, presented by SafetyChain Software. We present excerpts below. 

A few years ago, there was a very serious Salmonella outbreak in peanut butter. It appears that company shopped around for negative salmonella results and then shipped the product. It’s a worst case scenario, but in this case, short term profitability at the expense of food safety resulted in the over 600 illnesses and a few deaths as well as the bankruptcy of the company, described Savage.

Role of GMPs in Creating and Minimizing CCPs

Without good GMPs, facilities tend to have more CCPs than necessary. There has to be a good balance between GMPs and CCPs. When companies understand the the relationship between HACCP, GMPs, and CCPs, typically the HACCP plan would not have more than 3 or 4 CCPs and everything else is covered by GMPs. 

Best practices for HACCP management must be committed from the beginning and throughout the process. GMPs should be in place prior to even beginning to revamp the HACCP plan. Multidisciplinary HACCP teams, including QC, QA, Lab, Sanitation, Product Development and Sales, experts, should contribute to the process in developing the plan. Having a multidisciplinary team helps with achieving buy-in or company-wide commitment to the plan. 

Companies have been pretty good with monitoring, but there’s still some confusion between verification and validation. Verification is a check of the checkers. When CCPs are identified and monitored, verification is making sure that the company says what it’s doing and is doing what it says. Validation asks if the company has the right CCPs and how can they prove it. 

Best Practices for Audit Prep

USDA regulated plants have routine inspections to verify what the companies do on an everyday basis. Separate from these routine inspections, USDA also performs food safety assessments which can take days or weeks to complete. Companies under USDA jurisdiction should do their own food safety inspection to prepare for these FSIS audits. FDA regulated plants may go months or years between inspections. These facilities should have third party audits such as SQF or other audits. 

GFSI schemes have taken hold in the US and around the world. The popular one in the U.S. is SQF. Companies that meet SQF standards should have no problem meeting new FDA FSMA regulations.