From the Salmonella-in-low-moisture-foods file: survival for 180+ days in cookie and cracker sandwiches

In 2009 when PCA was distributing Salmonella-contaminated peanut paste products to lots of manufacturers, many were asking questions about how the pathogen survived in the low-moisture environment and whether the outbreak was an indicator that the snack food industry was facing a larger issue. Since then there have been numerous low-moisture food outbreaks (here’s a nice review from Sofia Santillana Farakos and Joe Franks).

Friends of barfblog Larry Beuchat (right, exactly as shown) and Scott Burnett did some work on peanut butter and Salmonella and showed that the pathogen could survive for a long, long time, Larry-Beuchat-28622-105-230x154‘Post-process contamination of peanut butter and spreads with Salmonella may to result in survival in these products for the duration of their shelf life at 5 degrees C and possibly 21 degrees C, depending on the formulation.’

Larry has published another great paper on Salmonella in low moisture foods, Survival of Salmonella in Cookie and Cracker Sandwiches Containing Inoculated, Low-Water Activity Fillings in JFP. From the abstract, ‘The ability of Salmonella to survive for at least 182 days in fillings of cookie and cracker sandwiches demonstrates a need to assure that filling ingredients do not contain the pathogen and that contamination does not occur during manufacture.’


Or in his own words,

“There have been an increased number of outbreaks of diseases associated with consumption of contaminated dry foods. We wouldn’t expect salmonella to grow in foods that have a very dry environment,” said Beuchat, who works with the Center for Food Safety on the UGA campus in Griffin.

Focusing on cookie and cracker sandwiches, the researchers put the salmonella into four types of fillings found in cookies or crackers and placed them into storage. The researchers used cheese and peanut butter fillings for the cracker sandwiches and chocolate and vanilla fillings for the cookie sandwiches.

These “are the kind that we find in grocery stores or vending machines,” Beuchat said.

“The salmonella didn’t survive as well in the cracker sandwiches as it did in the cookie sandwiches,” Beuchat said.

In some cases, the pathogen was able to survive for at least to six months in the sandwiches.“That was not expected,” he said.

Survival of Salmonella during baking of peanut butter cookies

Peanuts and peanut-based products have been the source of recent Salmonella outbreaks worldwide. Because peanut butter is commonly used as an ingredient in baked goods, such as cookies, the potential risk of Salmonella remaining in these products after baking needs to be assessed. This research examines the potential hazard of Salmonella in peanut butter cookies when it is introduced via the peanut-derived ingredient.

The survival of Salmonella during the baking of peanut butter cookies was determined. Commercial, creamy-style peanut butter was artificially inoculated peanut.butter.cookieswith a five-strain Salmonella cocktail at a target concentration of 108 CFU/g. The inoculated peanut butter was then used to prepare peanut butter cookie dough following a standard recipe. Cookies were baked at 350°F (177°C) and were sampled after 10, 11, 12, 13, 14, and 15 min. Temperature profiles of the oven and cookies were monitored during baking. The water activity and pH of the inoculated and uninoculated peanut butter, raw dough, and baked cookies were measured. Immediately after baking, cookies were cooled, and the survival of Salmonella was determined by direct plating or enrichment. After baking cookies for 10 min, the minimum reduction of Salmonella observed was 4.8 log. In cookies baked for 13 and 14 min, Salmonella was only detectable by enrichment reflecting a Salmonella reduction in the range of 5.2 to 6.2 log.

Cookies baked for 15 min had no detectable Salmonella. Results of this study showed that proper baking will reduce Salmonella in peanut butter cookies by 5 log or more.

Journal of Food Protection®, Number 4, April 2014, pp. 528-690 , pp. 635-639(5) ;

Lathrop, Amanda A; Taylor, Tiffany; Schnepf, James

Nestle Toll House cookie dough returns; Linda Rivera still hospitalized

In Room 519 of Kindred Hospital, Linda Rivera can no longer speak.

Her mute state, punctuated only by groans, is the latest downturn in the swift collapse of her health that began in May when she curled up on her living room couch and nonchalantly ate several spoonfuls of the Nestlé cookie dough her family had been consuming for years. Federal health officials believe she is among 80 people in 31 states sickened by cookie dough contaminated with a deadly bacteria, E. coli O157:H7.

The impact of the infection has been especially severe for Rivera and nine other victims who developed a life-threatening complication known as hemolytic uremic syndrome. One, a 4-year-old girl from South Carolina, had a stroke and is partially paralyzed.

But good news. Two weeks ago, Nestle announced, in breathless PR-speak,

After almost two months of being out of the U.S. marketplace, Nestle USA is pleased to announce that Nestle Toll House refrigerated cookie dough is returning to stores this week.

To make it easy for both retail partners and consumers to identify the new batch of cookie dough, a blue "New Batch" label will appear on all new production cookie dough items. Nestle Toll House shipping cases also are marked in blue (rather than the previous black) to denote new production and will contain the statement: "Do not consume raw cookie dough." The adoption of this distinct labeling is the result of helpful discussions between Food & Drug Administration (FDA) officials and Nestle, following reports of E.coli O157:H7 illnesses that appeared to be related to the consumption of raw cookie dough.

I bet the discussions were helpful. Probably similar to the ones ConAgra had with the U.S. Department of Agriculture geniuses who said, safe cooking instructions for frozen $0.50 pot pies should tell consumers to use a thermometer to make sure the pie is safe. Food safety is a shared responsibility apparently means it’s the consumer’s responsibility, especially in foods that may be perceived as ready-to-eat.

This is what the new Nestle cookie label looks like, on a package I picked up at a local store on Saturday (front, above, right; back, below, left).

Labeling is a lousy way to provide information about food safety risks, but better than nothing. I’m sure Nestle and ConAgra, in the best interests of their consumers, will publicly release the evaluative data they (probably? maybe?) acquired to show that these particular labels have a positive impact on consumer food safety behavior.