Poop in the field

Two new studies assess the risk of various manures in broccoli and spinach respectively.

cow.poop2In 2011 and 2012, trials consisting of experimental plots were carried out to evaluate the presence of pathogenic (Listeria monocytogenes, Salmonella) and prevalence of indicator (Escherichia coli) microorganisms in broccoli fertilized with liquid hog manure or mineral fertilizers and irrigated zero, one, or two times with E. coli–contaminated water.

In 2011, results showed that E. coli contamination in broccoli heads was affected by the interval between irrigation and sampling (P = 0.0236), with a significant decrease between the first and third day following irrigation (P = 0.0064). In 2012, irrigation frequency significantly increased E. coli prevalence in broccoli samples (P = 0.0499). In 2012, E. coli counts in the soil were significantly influenced by the type of fertilizer applied, as plots receiving liquid hog manure showed higher bacterial counts (P = 0.0006). L. monocytogenes was recovered in one broccoli sample, but geno-serogrouping differentiated the isolate from those recovered in manure and irrigation water. The L. monocytogenes serogroup IIA, pulsotype 188 strain was found in six soil samples and in irrigation water applied 5 days before soil sampling.

This study highlights the link between E. coli levels in irrigation water, irrigation frequency, and interval between irrigation and harvest on produce contamination. It also demonstrates that L. monocytogenes introduced into the soil following irrigation can persist for up to 5 days.

In the second study, the authors write that concerns about the microbiological safety of fresh produce have attracted attention in the past three decades due to multiple foodborne outbreaks. Animal manure contaminated with enteric pathogens has been identified as an important preharvest pathogen source.

This study investigated the survival of Salmonella enterica in dust particles of dehydrated turkey manure and how association with manure dust may enhance the survival of salmonellae on leafy greens in the field. The survival of a cocktail of multiple Salmonella serotypes in the dried fecal material of various particle sizes (125 to 500 μm) was examined at varying moisture contents (5, 10, and 15%). Survival times of the pathogen were inversely related to moisture content and particle size of manure dust, with viable Salmonella still detectable for up to 291 days in the smallest particle size (125 μm) with 5% moisture. Association with manure dust particles increased the survival of Salmonella when subjected to UV light both under laboratory conditions and on the surface of spinach leaves in a greenhouse setting.

poop ice creamThe results of this study suggest that aerosolized manure particles could be a potential vehicle for Salmonella dispersal to leafy greens if the microorganism is present in the dry manure.



Persistence of indicator and pathogenic microorganisms in broccoli following manure spreading and irrigation with fecally contaminated water: field experiment

Journal of Food Protection®, Number 10, October 2015, pp. 1776-1924, pp. 1776-1784(9)

Généreux, Mylène; Breton, Marie Jo; Fairbrother, John Morris; Fravalo, Philippe; Côté, Caroline



Survival of Salmonella Enterica in dried turkey manure and persistence on spinach leaves

Journal of Food Protection®, Number 10, October 2015, pp. 1776-1924, pp. 1791-1799(9)

Oni, Ruth A.; Sharma, Manan; Buchanan, Robert L



Leafy greens carry risks; at-home rinsing of pre-washed salad mix isn’t doing much

In the quest to get healthier, including losing weight and reducing my body fat percentage, I’ve been paying particular attention to my eating habits and eating a bunch more vegetables.

I’ve become increasingly fond of the convenience of pre-washed, bagged, fresh whatever. A staple of my weekly meals is 4oz of steak, a crumble of blue cheese, grilled mushrooms, sliced pear, a few walnuts all over a bed of 50/50 mix of pre-washed baby spinach and and mesclun mix.img86l

I just open the bag and throw it on the plate. Because there’s not much I can do, safety-wise, to it once it’s in my home. If there’s pathogenic E. coli, Listeria or Salmonella there (or others) I’m stuck with it. I’m following recommendations from a bunch of my food safety friends who reviewed the literature on cut, bagged, washed, ready-to-eat leafy greens from a few years ago. In the abstract, they write:

The panel concluded that leafy green salad in sealed bags labeled “washed” or “ready-to-eat” that are produced in a facility inspected by a regulatory authority and operated under cGMPs, does not need additional washing at the time of use unless specifically directed on the label.

Leafy green food safety risks need to be addressed before they get to me, all I can do by washing it again is increase the chance I cross-contaminate the salad precursor in my home. My purchasing choice is based in trust that growers, packers and processors know what they are doing, and do it. But at best, they can only remove 90% of what is there with a wash.

Last week some research was presented at the American Chemical Society National Meeting & Exposition, prior to peer-review, that states what lots of food safety folks have published over the past decade: washing leafy greens doesn’t result in a sterile salad and the bumpy leaves protect pathogens.


I talked to Korin Miller at Yahoo News about it,

Labels like “thoroughly washed” and “triple washed” make us feel comfortable chowing down on pre-washed baby spinach straight from the container. But researchers from the University of California, Riverside, say we might want to rethink that habit.

They discovered that the small peaks and valleys in baby spinach leaves can harbor bacteria — even during the washing process they often undergo in food-processing plants.

While the news is shocking to most people, “this is not a surprise to many of us in the food safety arena,” Mike Doyle, director of the Center for Food Safety at the University of Georgia, tells Yahoo Health.

Unfortunately, washing your pre-washed baby spinach before eating it doesn’t make a difference, says Benjamin Chapman, PhD, an assistant professor and food safety extension specialist at North Carolina State University.

“Rinsing isn’t going to do a whole heck of a lot for food safety,” Chapman tells Yahoo Health — it just may remove dirt or other physical objects that you can see. Cooking the spinach, however, will kill potentially harmful bacteria.

I don’t agree with this comment, ‘pre-washed baby spinach is typically treated using a bleach disinfectant’

But what about the whole “triple wash” label? Does that make pre-washed spinach safer? Chapman says there’s some confusion about what it means. Companies don’t triple wash spinach to disinfect it, he explains — they do it to reduce the likelihood of cross-contamination from one piece of spinach to another during the washing process.

The water is treated to reduce cross-contamination in the processing water; 2-log reduction, at the very best, is not an effective surface disinfectant.

Food safety culture means employees don’t contaminate food with brooms or forklift tires

If a company making ready-to-eat refrigerated deli-meats has a “strong culture of food safety,” would an employee shake a broom over a line of processed product?

If more inspectors are the answer to safer food, why would the inspectors need publicly reported accounts of foodborne illness and death to try harder?

And if the company and inspectors are doing lots of tests to ensure enhanced food safety, why aren’t they bragging about it instead of requiring an Access to Information request by a media outlet to discover that inspectors continue to find problems with Maple Leaf Foods infamous Bartor Road plant in Weston, Ontario.

Last night, Steve Rennie of The Canadian Press reported that Canadian federal food safety types found a troubling lack of hygiene at Maple Leaf Foods’ Toronto facility just weeks after it reopened last year from a temporary shutdown for cleaning – after 22 people were killed and 53 sickened with listeria linked to deli meat.

A Canadian Food Inspection Agency inspection report dated Oct. 10, 2008, found:

• slime on part of the meat-trimming table in the curing room;
• meat debris on two steel container bins and unidentified debris on the brine tank in the curing room;
•a moist and mouldy cardboard sheet on the base of a skid in the curing room that holds bags of salt;
•mouldy caulking on the walls of the meat-defrosting room;
•a stack of dirty, mouldy and broken skids left in the frozen packoff room during cleaning;
• food debris on knife holders, floor and meat containers in the formulation room; and,
• rust on equipment used to process mock chicken.

The Canadian Press obtained that inspection report and others under the Access to Information Act.

Another report says during visits on Oct. 20 and 21, an inspector watched as "an employee in a grey jacket lifted a floor broom over a finished food product conveyor belt during operation to sweep in between the conveyors." (No additional information as to whether the product was packaged or not).

Then on Oct. 22, the inspector saw a worker using a forklift to move ready-to-eat link sausages from the cooler to a line for packaging. The report notes the meat at the bottom part of the lift "was not protected for the potential wheel over spray or splash cross contamination."

That part is gross. And unacceptable.

On Aug. 23, 2008, (barfblog.com passim ad nauseum) Maple Leaf CEO Michael McCain took to the Intertubes to apologize for an expanding outbreak of listeriosis that would eventually kill 22 people. As part of his speech, McCain said that Maple Leaf has “a strong culture of food safety.”???

On Aug. 27, 2008, McCain told a press conference, ??????“As I’ve said before, Maple Leaf Foods is 23,000 people who live in a culture of food safety. We have an unwavering commitment to keep our food safe, and we have excellent systems and processes in place.

Dr. Randy Huffman, Maple Leaf’s chief food-safety officer, took to his company’s Journey (worst band ever)-inspired Journey to Food Safety Leadership blog to say today,

“The average reader must be wondering how this plant could have so many issues only a month after re-opening from causing one of the worst food safety crises in Canada.”

I’m not sure what he means by average. I consider myself dull and below-average; does that mean I won’t be able to understand what he is saying?

Huffman: Over the past 12 -14 months- since these inspections were conducted – we have invested over $5 million in upgrades at the Bartor Road plant. This includes repair of floors and wall surfaces, air handling systems, caulking, better separation of raw and cooked areas of the plant, new pallets and new slicing and packaging equipment. We have implemented over 200 new operating procedures.

Why did it take 22 deaths and 53 illnesses to make this food safety investment?

Huffman: CFIA generates these reports and so does Maple Leaf, through our own inspections across all our plants. We welcome this government scrutiny.  Canadians hold us to a higher standard, as they should.

So why did the reports have to be obtained through an Access to Information request, and why doesn’t Maple Leaf just sidestep the government and make the reports public, along with other data, as it becomes available, to build trust with the buying consumer?

Would more inspectors have helped? Maybe if they were looking. Federal food inspection union thingy Bob Kingston said,

"In a normal operation that had not been through what they had been through, that might be a common occurrence. But in this facility, it’s very surprising that that would still be there. Because you would expect it to be spotless."

The best food producers, processors, retailers and restaurants will go above and beyond minimal government and auditor standards and sell food safety solutions directly to the public. The best organizations will use their own people to demand ingredients from the best suppliers; use a mixture of encouragement and enforcement to foster a food safety culture; and use technology to be transparent — whether it’s live webcams in the facility or real-time test results on the website — to help restore the shattered trust with the buying public.

And the best cold-cut companies may stop dancing around and tell pregnant women, old people and other immunocompromised folks, don’t eat this food unless it’s heated