Listeria Tracking and Whole Genome Sequencing - How Close is Close

As the CRF frozen produce recall has resulted in a cascade of recalls and millions of pounds of produce being pulled from shelves across the country, one can look at what triggered this - an Ohio Lab finding Listeria in frozen foods and an investigation of a frozen food plant that led to finding the organism in the plant.

According to CDC: Epidemiological and laboratory evidence available at this time indicates that frozen vegetables produced by CRF Frozen Foods of Pasco, Washington and sold under various brand names are one likely source of illnesses in this outbreak. This is a complex, ongoing investigation, and updates will be provided when more information is available.

Further in that report

Whole genome sequencing showed that the Listeria isolate from the frozen corn was closely related genetically to seven bacterial isolates from ill people, and the Listeria isolate from the frozen peas was closely related genetically to one isolate from an ill person. This close genetic relationship provides additional evidence that some people in this outbreak became ill from eating frozen vegetables produced by CRF Frozen Foods.

Whole genome sequencing has had a huge impact on outbreak investigations.  It allows investigators to match the organism involved in an outbreak back to the organisms found in the plant.  Using this output, one can look in time to past illness and do the same matching, what is termed retrospective analysis. But just because that organism is found in food or in the food plant, does that implicate that food? And how close is close when CDC says there is a close genetic relationship? We asked Dr. Edward Dudley of Penn State to provide some insight.

"A 5 base pair difference (or 5 SNPs) is strong evidence that the two are related. [Listeria has 3 million base pairs]  Even within an outbreak, it isn’t unusual for clones to vary by a few SNPs. This is one of the reasons the FDA is sequencing large collections of food borne pathogens including Listeria, in order to get a handle on how much genetic variation exists in natural populations. As we collect more of this data, it will tell us how quickly the DNA of these pathogens change in foods, food processing environments or during an outbreak, informing us how many SNPs should be allowed for us to still make strong case that two isolates are related."

"Keep in mind though, that genome sequencing should not be used by itself to make any conclusions. We still need the epidemiological (epi) data that provides a statistical link between the patient and an event, for example "did patients with Listeria eat frozen vegetables more commonly than healthy individuals during the time frame of the outbreak?”. The genome sequencing of isolates obtained from patient and foods is used to support the conclusions of the epi investigation when isolates from linked sources are found to be highly related on the DNA level."

So in the end, old fashion epidemiological evidence is still needed.   And there is still understanding is needed.  As for produce, many of the companies forced into a recall are doing so without knowing if there is actually Listeria in their product and in the absence of illnesses associated with their product.

Chipotle Retains Food Safety Gurus as Board Wants Ability to Pick Executive Board

Chipotle shareholders approved a proposal to give the chain's board approval to be able to nominate directors to the board.  At the same time, the chain acknowledge that it had hired two additional food safety experts.

Reuters
http://www.reuters.com/article/us-chipotle-shareholders-idUSKCN0Y2049
Business | Wed May 11, 2016 6:22pm EDT
Chipotle shareholders vote for more power to pick board
LOS ANGELES | By Lisa Baertlein

CRF Recall Triggers Recalls by Additional Processors and Retailers

A number of other packers of frozen foods issued recalls after an ingredient supplier, CRF issued a recall last week.  What started off as a massive recall continues to get bigger as product produced by CRF was repacked by other frozen food companies.

The list below in includes recalls from Stahlbush Island Farms, Harris Teeter, Twin Cities, Pictsweet, and NORPAC.

Walnuts Recalled Due to Listeria

A Woodstock, NJ company is recalling various Walnut products purchased from Gibson Farms after a sample of that product tested positive for Listeria monocytogenes.   This comes after another recall last week for sunflower seeds, although there does not appear to be any real connection.

Makes you wonder whether people will start testing the heck out of nut products for Listeria?  These products, because of low moisture / water activity, will not support the growth of Listieria.  And because they are produced in a dry environment, one would expect that environmental contamination would be minimal.  That being said, one would expect levels to be very low.

The biggest risk for these nuts would be if they were added as an ingredient to a product that supported growth.  And depending on the level, which would be expected to be very low, would only be a risk to those with a highly impaired immune system.

With two recalls, more research is needed to understand how Listeria is getting onto nuts, the levels present, and what real risk it poses.


FDA Recall Notice
http://www.fda.gov/Safety/Recalls/ucm500345.htm
United Natural Trading LLC Announces Voluntary Recall of Walnuts
For Immediate Release
May 10, 2016

Hoijicha Tea Recalled Due to Salmonella in Ingredient

Frontier Natural Product Co-op based in and a self proclaimed 'major supplier in the booming natural products industry', is recalling Organic Hojicha Tea due to potential to be contaminated with Salmonella. The recall indicates the recall was initiated after an ingredient tested positive for Salmonella. (While it seems the supplier did the testing, it is hard to determine from how the notice was written.)..

So what is Hojicha tea? Good question.  Well, Hojicha tea is a roasted tea that is more mild and has less caffeine. The roasting process makes the tea leaves reddish in color and gives the tea a ' a toasty, slightly caramel-like flavor'. Because of the lower caffeine level, it is often served with dinner.

So how would Salmonella get in the Hojicha?  Another good question.  If the tea supplier was responsible, and being the leaves were roasted, it would have to be a case of cross contamination in the post-roasting environment.


FDA Recall Notice
http://www.fda.gov/Safety/Recalls/ucm500342.htm

Frontier Co-op Initiates Voluntary Recall of Organic Hojicha Tea Due to Possible Health Risk

CRF Vegetables Leads to Recall of Fried Rice Product Which Leads to Recall of Chicken Fried Rice Product

In a series of recalls following the CRF vegetable recall - Ajinomoto Windsor, Inc recalled its fried rice products because they had CRF as a supplier of the vegetables used in the rice mixes.  This then triggered Garland Ventures LTD, a Garland, Texas establishment to recall 114,870 pounds of chicken fried rice products.  Both items are considered not ready-to-eat.

FDA Recall Notice
http://www.fda.gov/Safety/Recalls/ucm499858.htm
Ajinomoto Windsor Recall of Products Related to CRF Frozen Vegetable Recall
For Immediate Release
May 7, 2016

Sunflower Seed Recall Forces a Large Cascade of Recalls

After SunOptima issued a recall for Listeria in sunflower seed, a number of their customers issued recalls.  Probably more to come?

One this that would be good to know is how the sampling / testing occurred after product had shipped and was utilized by their customers.

Recalls listed below:

Related Frozen Foods Recalls Point to Weakness in Supply Chain Controls - Only as Good as Your Supplier's Supplier

Two recalls for Listeria have been announced in wake of the CRF frozen produce recall, with probably more to come,   One is from ConAgra Foods for organic frozen corn and peas sold under the Trader Joe's and Watts Brother labels.  The other issued recall was by a Texas firm that is recalling fresh corn relish and bean salad.  There will no doubt be more recalls to come as companies evaluate their supply chain.

At the heart of this is a very complex supply chain. CRF and Oregon Potato, two frozen food companies based in the Northwest are ground zero.  The problem is that these companies produce product not only for retailers, but also for other manufactures through sales of bulk frozen product.  What happens is this...as these seasonal produce items are harvested, much of it goes into bulk.  Bulk allows manufacturers to repack product as needed to meet customer demand throughout the year. Within a given season, one company may pack more corn than they have sales for, so they sell bulk product to someone else who needs that product to fill their own orders.  These transfers occur throughout the year and allow companies to be efficient in meeting the demand of their customers.  That is the good part.

The problem arises when one of the companies has an issue, say Listeria, that then affects the whole chain.   For example, Company A is repacking some mixed vegetable product and needs to purchase bulk peas or onions form Supplier B to help fill the order..  Now Company A, who has a great internal Listeria program, purchases Supplier B who may or may not have a good Listeria Program.. Supplier B provides a COA showing that lot was good (Listeria negative).  But FDA makes a visit to Supplier B and in conducting environmental testing, they find Listeria in Supplier B's facility..  It could even be that Supplier B sold product to another company who is then implicated in an outbreak that traces back to Supplier B.  In these cases, Company A must conduct a recall.

This can even go further back.  Supplier B was a little short on onions and purchased onions from Supplier C to help fill their order to Company A. And it is found that Supplier C has an issue.  That issue now becomes a problem for Supplier B as well as Company A.  And if Company A is producing product for 10 different retailers, now you have a whole lot of retailers having to recall product.  And if Supplier C was also selling bulk product to two other repacking companies who were producing product for a dozen more retailers, we can easily see how this can expand.

It is difficult to ensure that suppliers are adequately controlling risk, it can even be harder to make sure that the supplier's supplier is adequately controlling risk.  Unfortunately, as logistics / purchasing people look to take advantage of co-packing opportunities, the true cost of risk control may not be considered.  These costs can include extensive product testing, on-site visits, insistence that supplier institute aggressive Listeria control programs, etc.  To be fair, Listeria control was probably not on many people mind when these deals were made.  However, moving forward, it must become a part of the picture.


FDA Recall Notices
http://www.fda.gov/Safety/Recalls/ucm499623.htm
Company Announcement
When a company announces a recall, market withdrawal, or safety alert, the FDA posts the company's announcement as a public service. FDA does not endorse either the product or the company.
Watts Brothers Farms Organic Mixed Vegetables, Organic Super Sweet Corn, And Organic Peas And Trader Joe's Organic Super Sweet Corn Recalled Because Of Possible Health RiskFor Immediate Release

Nut Products Recalled After Sunflower Seed Supplier Notifies of Potential Listeria Contamination

Tree House Foods is recalling a wide variety of snack bars and nut / trail mixes after receiving notification from their supplier that the sunflower seed may contain Listeria monocytogenes.  Sun Optima, a Canadian firm, is also recalling sunflower seed products.

Sunflower seed would be considered a low risk product since they would not support growth, however the ingredient would be added as a RTE ingredient.

 
PRN Newsire
http://www.prnewswire.com/news-releases/treehouse-foods-issues-voluntary-product-recall-due-to-possible-health-risk-300262111.html
TreeHouse Foods Issues Voluntary Product Recall Due to Possible Health Risk