19 sickened with E. coli O157 from chicken salad: Source not IDed but fast recall by Costco may have limited outbreak

The U.S. Centers for Disease Control, the U.S. Food and Drug Administration (FDA), the U.S. Department of Agriculture Food Safety and Inspection Service, and public health officials in several states investigated an outbreak of Shiga toxin-producing Escherichia coli O157:H7 (STEC O157:H7) infections.

chicken_salad_sandPublic health investigators used the PulseNet system to identify illnesses that were part of this outbreak. PulseNet, the national subtyping network of public health and food regulatory agency laboratories, is coordinated by CDC. DNA fingerprinting is performed on E. coli bacteria isolated from ill people by using a technique called pulsed-field gel electrophoresis, or PFGE. PulseNet manages a national database of these DNA fingerprints to identify possible outbreaks.

One DNA fingerprint (outbreak strain) was included in this investigation. A total of 19 people infected with the outbreak strain of Shiga toxin-producing STEC O157:H7 were reported from seven states. The majority of illnesses were reported from the western United States. The number of ill people reported from each state was as follows: California (1), Colorado (4), Missouri (1), Montana (6), Utah (5), Virginia (1), and Washington (1).

Among people for whom information was available, illnesses started on dates ranging from October 6, 2015 to November 3, 2015. Ill people ranged in age from 5 years to 84, with a median age of 18. Fifty-seven percent of ill people were female. Five (29%) people were hospitalized, and two people developed hemolytic uremic syndrome, a type of kidney failure. No deaths were reported.


The epidemiologic evidence collected during this investigation suggested that rotisserie chicken salad made and sold in Costco stores was the likely source of this outbreak.

State and local public health officials interviewed ill people to obtain information about foods they might have eaten and other exposures in the week before their illness started. Fourteen (88%) of 16 people purchased or ate rotisserie chicken salad from Costco.

On November 20, 2015, Costco reported to public health officials that the company had removed all remaining rotisserie chicken salad from all stores in the United States. This voluntary action taken by Costco may have prevented additional illnesses. Costco also worked in collaboration with public health officials during the investigation by providing records and information related to ingredient suppliers to try to determine the source of the outbreak.

The Montana Public Health Laboratory tested a sample of celery and onion diced blend produced by Taylor Farms Pacific, Inc. and collected from a Costco store in Montana. Preliminary results indicated the presence of E. coli O157:H7. This product was used to make the Costco rotisserie chicken salad eaten by ill people in this outbreak. According to the FDA, further laboratory analysis was unable to confirm the presence of E. coli O157:H7 in the sample of celery and onion diced blend.

As a result of the preliminary laboratory results and out of an abundance of caution, on November 26, 2015, Taylor Farms Pacific, Inc. voluntarily recalled the celery and onion diced blend and many other products containing celery because they might be contaminated with E. coli O157:H7.

The FDA conducted a traceback investigation of the FDA regulated ingredients used in the chicken salad to try to determine which ingredient was linked to illness. However, the traceback investigation did not identify a common source of contamination.

This outbreak appears to be over.

Chapman wins (but no one wins in foodborne outbreaks) it was the celery: Taylor Farms Pacific, Inc. recalls celery, E. coli linked to Costco outbreak

Taylor Farms Pacific, Inc. of Tracy, CA, is recalling the products listed below because they may include celery which could potentially contain E. coli O157:H7.

costco.chicken.salad.nov.15The products listed below are being recalled out of an abundance of caution due to a Celery and Onion Diced Blend testing positive for E. coli O157:H7 in a sample taken by the Montana Department of Health. The Celery and Onion Diced Blend tested by the state of Montana was used in a Costco Rotisserie Chicken Salad that has been linked to a multi-state E. coli 0157:H7 outbreak.

Consumers may call 209-830-3141 for any further information Monday to Friday, exclusive of holidays, between the hours of 8am-5pm (PST). Consumers with concerns about an illness from consumption of any of the recalled products should contact a health care provider.

Taylor Farms produce mixture fingered in Costco chicken salad/E. coli O157 outbreak

A retailer or food service operator is only as good as the ingredients they use. Even with the best internal food safety programs, a good food safety culture includes supplier standards and verifications. Audits and inspections are never enough.

According to the Associated Press, Costco believes that contamination of their rotisserie chicken salad is linked to produce.costco.chicken.salad_.nov_.15

Costco officials say testing has pointed toward a vegetable mix from a California food wholesaler as the source of E. coli in the company’s chicken salad that has been linked to an outbreak that has sickened 19 people in seven states.

Craig Wilson, Costco vice president of food safety and quality assurance, said Wednesday he was told by the Food and Drug Administration that the strain of E. coli seems to be connected to an onion and celery mix.

Wilson says the company uses one supplier for those vegetables in the chicken salad sold in all its U.S. stores.

He says one additional test is needed to confirm that the vegetables carried the same E. coli strain connected with the outbreak.

Wilson identified the supplier as Taylor Farms in Salinas, California.

Minnesota vs. California: Investigators can’t identify source of E. coli O157 outbreak; celery or caterers suspected

The root of last summer’s E. coli outbreak linked to California grown celery remains a mystery. After six months of inspections and testing, investigators found no local sources of E. coli contamination – good news for Salinas Valley growers and packers.

celery.farmExcept testing proves not much.

Last July, 57 people were sickened and nine were hospitalized in Minnesota with E. coli O157:H7. All of the victims ate celery or potato salad made with celery at events catered by the same company. Government investigators traced the celery to Martignoni Ranch just north of Gonzales, grown by Costa Farms of Soledad. The celery was cooled and packed by Mann Packing in Salinas.

An attorney representing the victims believes the E. coli contamination started with the caterer, not the growers or packers.

“This report will help get the case resolved,” said William Marler, managing partner of the Marler Clark law firm in Seattle. “We believe the caterer is likely to settle,” he said, since the company won’t be able to point the finger at anyone else.

In late January, the California Department of Public Health completed its initial inquiry into the incident, which state officials conducted in cooperation with the federal Food and Drug Administration. Investigators found no E. coli in seven soil and water samples taken from the ranch. During their inspection, they didn’t see any problems that might have contributed to cross-contamination. And the investigators could not find signs of contamination from a defunct dairy operation next door.

Tainted celery linked to Gonzales farm

An outbreak of E. coli in Minnesota has been linked to celery grown in Gonzales, but the attorney representing many of the sickened people said Thursday that he is not, yet, targeting the grower.

celery.potato.saladAccording to a recently released report by the Minnesota Department of Health, 57 people were sickened and nine were hospitalized. The victims were members of a band of the Lake Superior Chippewa called Fond du Lac. Fortunately, none of the victims developed a potentially deadly kidney condition common to the identified strain: E. coli O157:H7, according to documents obtained from the MDH.

MDH found that the most common food items were the celery and onions. Potato salad, which included celery and onions, was found to be tainted with E. coli O157:H7. Cases were also identified at events where potato salad was not served, but celery was. The celery was traced back to a field adjacent to a defunct dairy operation near Gonzales, according to the MDH.

MDH concluded that the common server at five Fond du Lac events – including an Elder picnic and a wedding ceremony – between July 1 and July 17 on the reservation was Jim-N-Joe’s Northland Katering. The catering business produced invoices showing the celery was purchased from Upper Lakes Foods Inc., which provided bills of lading from Pro*Act, a Vancouver produce distributor, and Salinas-based Mann Packing.

The two distributors worked together to identify the “field of interest,” and the celery was traced back to Martignoni Ranch block 5c outside of Gonzales. Aerial views of the field show it butting up against a dairy operation, which Bill Marler, the attorney for several of the victims, described as “defunct.”

But a call placed to the dairy, M and M Dairy Inc., and to Rocci Martignoni, who is listed as president of M and M, was not immediately returned Thursday. But inspectors for the California Department of Public Health took water and soil samples from the field and did not find the pathogen.

Michael Needham, chief of the Emergency Response Unit for the California Health Department, said Thursday that his understanding was that no E.coli was discovered on the farm, but added that his report is not yet complete.

Because there is no scientific smoking gun connecting the celery in the potato salad to the farm the celery was grown on, Marler said he is reluctant to file a lawsuit against Martignoni. He is, however, filing a lawsuit against the caterer.

“I don’t feel like I have enough evidence to bring a lawsuit against the celery grower,” Marler said Thursday from his Seattle office. “But that may change as discovery proceeds and new evidence surfaces.”

Was it the celery? 74 sickened with E. coli O157:H7 associated with Jim-N-Jo’s Northland Katering, Minnesota:, July 2014

Bill Marler has kindly made public the final health report regarding the E. coli O157:H7 outbreak that sickened at least 74 people attending a July picnic for Elders of the Fond du Lac Band of Lake Superior Chippewa, in Minnesota.

CeleryOn July 17, 2014, a physician called the Minnesota Department of Health (MOH) to report that five individuals had been treated in the emergency department at Community Memorial Hospital in Cloquet for bloody diarrhea. All five cases had reported attending a picnic for Elders of the Fond du Lac Band of Lake Superior Chippewa on July 11that was catered by Jim-N-Jo’s Northland Katering. The caterer is licensed by the University of Minnesota (UMN) and operated out of a kitchen located at the Cloquet Forestry Center. MOH Environmental Health (EH), UMN EH, Fond du Lac Human Services, and MOH Tribal Relations were notified and an investigation was initiated.


Cases were identified through routine laboratory surveillance and interviews with event attendees identified through contact information provided by event hosts. A case was defined as an individual who attended an event catered by Jim-N-Jo’s Northland Katering and subsequently developed diarrhea (3 loose stools in a 24- hour period) that was either bloody or at least 3 days in duration, or an individual who had E. coli 0157:H7 isolated from a stool culture with a pulsed-field gel electrophoresis (PFGE) pattern indistinguishable from or within 3 bands of the main outbreak pattern by at least 1enzyme (Xbal or Bin i ). All Shiga toxin-producing E. coli cases reported to MOH are interviewed about potential exposures, including food consumption, as part of routine enteric disease surveillance. Event attendees identified through event hosts were interviewed about food consumption at the event and illness history.

Stool samples from consenting patrons and food workers were submitted to the MDH Public Health Laboratory (PHL} for bacterial and viral testing.

A UMN sanitarian visited the catering facility on July 18 to evaluate food preparation and handling procedures, interview employees, collect food invoices, and gather contact information and menus for catered events.

The Minnesota Department of Agriculture (MDA) conducted traceback investigations of food items of interest to determine the source and possible routes of contamination of those items. MDA also collected samples of suspected products from the caterer for E. coli 0157:H7 testing by the MDA Laboratory. All E. coli 0157:H7 isolates recovered from food were forwarded to the MOH PHL for PFGE subtyping.


A total of 199 individuals from seven catered events were interviewed. Of these, 74 (37%) reported recent gastrointestinal illness, including 57 (29%) who met the case definition. Seventeen individuals were excluded from analysis; 16 attendees reported i!!ness that did not met the case definition, and 1individual possibly represented a secondary infection to an ill household contact. The state of residence was reported as Minnesota for 48 cases, Wisconsin for 4, Alabama for 2, Illinois for 1, Indiana for 1, and Ohio for 1.

celeryThirty-seven (65%) of the cases were female; the median case age was 62 years (range, 4 to 85 years). All cases reported diarrhea, 55 {96%) cramps, 35 (61%) bloody stools, 21 (37%) vomiting, and 11(19%) fever. The median incubation for cases was 91 hours (range, 9 to 174 hours); the median duration of illness was 157 hours (range, 52 to 288 hours) for the 11cases who had recovered by the time of interview. Illness onset dates ranged from July 8 to July 23. Twenty-one {37%) cases sought medical care at a clinic, 18 (32%) were seen at an emergency department, and 9 (16%) were hospitalized. Hospitalizations ranged from 2 to 6 days. !’Jo cases were diagnosed with hemolytic uremic syndrome or died.

Twenty-seven laboratory-confirmed cases representing three different catered events were identified, including seven ill individuals who originally tested negative for Shiga toxin by Meridian lmmunoCard STAT! EHEC at a clinical laboratory. Multiple closely related Xbal and Bin i patterns were observed among attendees of each event. Nineteen (70%) isolates were indistinguishable by Xbal from the subtype designated EXHXOl.0238 by the Centers for Disease Control and Prevention (CDC) (Minnesota pattern designation MN1393), five (19%) isolates were designated as EXHXOl.0074 (Minnesota pattern designation WAl), and one isolate each was designated as EXHXOl.0696, EXHXOl.0344, and EXHXOl.0248. Each of these patterns was two or fewer bands different from the main pattern Xbal with the exception of EXHXOl.0344, which was four bands different from the main pattern and two bands different from WAl. By Bini, 20 (74%) isolates were designated as EXHA26.1045, 6 (22%) isolates were designated as EXHA26.0621, and 1isolate was designated as EXHA26.1577.

During the initial follow-up with the Fond du Lac Band, it was discovered that many of the attendees of the Elder Picnic also might have had attended a Veteran’s powwow held July 12-13 on the reservation. The food for this event was provided by several licensed operators, but did not include Jim-N-Jo’s Northland Katering. The powwow was ruled out as the source of illness because only two ill individuals reported only attending the Veteran’s powwow. All other attendees of the powwow also attended an event catered by Jim-N-Jo’s.

Jim-N-Jo’s catered at least 12 events from July 5 to July 17. Menus and contact information for attendees were available for six events. Illness that met the case definition was identified at four of these events (July 11, picnic on the Fond du Lac Reservation; July 12, wedding; July 14-16, 3-day conference for a private company; and July 16, focus group on the Fond du Lac Reservation), and an additional case was identified through routine surveillance that attended an event hosted by Carlton County on July 17 that was also catered by Jim-N-Jo’s.

Of the 199 individuals interviewed, 122 (61%) attended the picnic on July 11; among these, 43 (35%) cases were identified. One culture-confirmed case reported onset of illness on July 8 before attending the picnic and could not recall attending any other catered events. However, the case did report taking part in other activities sponsored by the tribe that may have been catered by Jim-N-Jo’s . The food served at the picnic inciuded hamburgers, hot dogs, brats, chicken breasts, buns, condiments,onion, lettuce, tomato, cheese slices, sauerkraut, baked beans, potato salad, fruit salad (watermelon, cantaloupe, pineapple, honeydew, and strawberries), corn, chips, cookies, and packaged beverages. In the univariate analysis including attendees of the picnic, consumption of potato salad (37 of 38 cases vs. 44 of 66 controls; odds ratio [OR], 18.5; 95% confidence interval [Cl], 2.4 to 143.9; p < 0.001) was associated with illness.

Twenty-two of the individuals interviewed attended the focus group on Ju!y 16; two (9%) met the case definition (both were culture-confirmed). Of these, one case also attended the Elder picnic and reported onset of illness before the focus group. The menu for the focus group included a build-your-own salad buffet with several types of cut leafy greens, chicken, numerous vegetable toppings, bread and butter, strawberries, cookies, and water. Fresh celery and onions were available as vegetable toppings.

The wedding on July 12 was attended by approximately 300 people. Only a partial list of wedding attendees was provided. Of the 20 people interviewed, 9 (45%) met the case definition (including 5 cases who were culture­ confirmed). The menu for the wedding included pulled pork sandwiches, buns, cheese, onions, fruit salad (watermelon, cantaloupe, pineapple, honeydew and strawberries), vegetable tray (carrots, celery, broccoli, and cauliflower), dill dip, ranch dip, cheesy potatoes, baked beans, corn, packaged beverages, and cupcakes not provided by the caterer. Among wedding guests, no food was statistically associated with illness. However, consumption of celery sticks (5 of 9 cases vs. 2 of 8 controls; OR, 3.75; 95% Cl, 0.5 to 29.8; p = 0.33), and cantaloupe (6 of 8 cases vs. 3 of 7 controls; OR, 4.0; 95% Cl, 0.4 to 35.8; p = 0.31) had elevated odds ratios. The original menu provided to MOH did not include chopped onions that were available as a sandwich garnish. Five of nine cases were re-inten1iewed about onion consumption; no cases reported consuming onions at the event.

Twelve of the 21 people who attended the 3-day conference (July 14-16) were interviewed; three cases were identified. Lunch was served each day (July 14: pulled pork sandwiches, cheese, onions, potato salad, fruit salad, and cookies; July 15: salad, wild rice, red potatoes, beef tips, grapes, bread, and cookies; and July 16: chicken wild rice soup, make-your-own sandwich buffet, cookies, and banana bread). The small number of cases and controls precluded a meaningful statistical analysis among conference attendees.

No list of attendees was provided for the meeting held on July 17. One case was identified through routine surveillance who attended the event. The case reported eating ham, turkey, sausage, lettuce, tomato, cucumber, potato salad, strawberries, and a cookie.

Raw celery and onions were the only food items served at all five events with identified cases. Three events (picnic, 3-day conference, and meeting) were served the same batch of potato salad that contained raw celery and onions. The celery was also served as part of a vegetable tray at the wedding and a chopped garnish on the salad bar for the focus group. Chopped onions were also available at all events. In the univariate analysis including all events, consumption of celery (46 of 52 cases vs. 55 of 95 controls; OR, 5.6; 95% Cl, 2.2 to 14.3; p <0.001) was significantly associated with illness, and onions (42 of 51 cases vs. 61of 90 controls; OR, 2.2; 95% Cl, 1.0 to 5.2; p = 0.08) approached a statistically significant association with illness. In a multivariate model, only consumption of celery (adjusted OR, 10.1;p = 0.004) was significantly associated with illness.

UMN sanitarians visited the catering kitchen on July 18. All five employees were interviewed. One employee reported onset of diarrhea on July 14 and recovery on July 16 and worked while ill during July 15-16. A stool specimen submitted by the employee was positive for E. coli 0157:H7 with the main outbreak PFGE pattern. The employee reported sampling or tasting food during preparation.

Ingredients and preparation procedures for menu items were reviewed. The sanitarian noted inconsistent glove use and issues with date marking. No improper practices or procedures were noted with regard to cooking, cooling, or cross-contamination. The ingredients for the potato salad that was served at the picnic, 3-day conference, and meeting were prepared over a 3 day period. On July 7, the potatoes were boiled and cooled; on

July 8, celery and onions were washed and cut; and on July 9, potatoes were peeled and cut, and potato salad ingredients (potatoes, celery, onions, hard boiled eggs, mayonnaise, mustard, dried dill, sugar, pickle juice, vinegar, salt, pepper, and commercially prepared potato salad) were assembled and mixed separately into four 5-gallon bins. The celery that was served at the wedding was cut into sticks on July 10, stored in water, and added to the vegetable tray on July 12. The celery that was served at the focus group was chopped sometime during July 7-15 and stored in water before the event.

On July 21, an MDA inspector picked up leftover food from the caterer that was served at the implicated events, including potato salad, strawberries, honeydew, pineapple, and cantaloupe . The potato salad was positive for E. coli O157:H7; all other food samples were negative. Multiple PFGE subtypes were isolated from the potato salad, including the two main patterns isolated from the cases and two other closely related patterns that were not found among the case isolates. Additionally, on July 28, leftover celery and onions from the same shipment as what had been served in the potato salad, at the wedding, and the focus group were collected from the caterer and tested. Both products were negative.

The caterer ordered all fresh produce from Upper Lakes Foods, Inc. The celery that was served at all of the events was received by the caterer on June 25 in a case of 24 heads. MDA worked with Pro*Act distributing and Mann Packing to identify the field in California where the celery was grown as Martignoni Ranch block Sc. The California Department of Public Health {CDPH) was notified of the outbreak and traceback investigation and was able to confirm that the field was owned by Costa Farms and harvested by Mann Packing. The field is adjacent to a defunct dairy operation north of Gonzales, California in the Salinas Valley. CDPH notified the California Food Emergency Response Team {CalFERT) which conducted an inspection of the field and collected five water and soil samples on August 13. No potential cross-contamination issues or positive environmental samples were detected. The inspectors reported that grazing cattle are occasionally present in the adjacent field, but were not in sight at the time of inspection.

Nationally, one additional E. coli O157:H7 case with an isolate that was indistinguishable by PFGE was identified in Indiana. The case reported onset of illness on July 2 and no travel to Minnesota. No connection was found to the Minnesota outbreak.


This was a foodborne outbreak of E. coli O157:H7 infections associated with multiple events catered by Jim-N­ Jo’s Katering. Cases were associated with five events that took place from July 11to July 17. Potato salad served at three events was found to be contaminated with E. coli 0157:H7 that was indistinguishable from case isolates by PFGE. Cases were also identified at two additional events that did not serve the potato salad, but served celery that was from the same shipment as the celery in the potato salad. Contaminated celery that was served in some form at all five events was the most likely vehicle of transmission. The source of contamination was not identified, but sampling in the field was limited. It is still plausible that celery could have become contaminated during production.

Listeria monocytogenes transfer during mechanical dicing of celery and growth during subsequent storage

The transfer of Listeria monocytogenes to previously uncontaminated product during mechanical dicing of celery and its growth during storage at various temperatures were evaluated. In each of three trials, 275 g of retail celery stalks was immersed in an aqueous five-strain L. monocytogenes cocktail to obtain an average of 5.6 log CFU/g and then was diced using a celery.fresh.cuthand-operated dicer, followed by sequential dicing of 15 identical 250-g batches of uninoculated celery using the same dicer. Each batch of diced celery was examined for numbers of Listeria initially and after 3 and 7 days of storage at 4, 7, and 10°C. Additionally, the percentage by weight of inoculated product transferred to each of 15 batches of uninoculated celery was determined using inoculated red stems of Swiss chard as a surrogate. Listeria transfer to diced celery was also assessed after removing the Swiss chard. L. monocytogenes transferred from the initial batch of inoculated celery to all 15 batches of uninoculated celery during dicing, with populations decreasing from 5.2 to 2.0 log CFU/g on the day of processing. At 10°C, Listeria reached an average population of 3.4 log CFU/g in all batches of uninoculated celery. Fewer batches of celery showed significant growth during storage at 4 and 7°C (P < 0.05). Swiss chard pieces were recovered from all 15 batches of celery, with similar amounts seen in batches 2 to 15 (P > 0.05). L. monocytogenes was also recovered from each batch of uninoculated celery after the removal of Swiss chard, with populations decreasing from 4.7 to 1.7 log CFU/g. Storing the diced celery at 10°C yielded a L. monocytogenes generation time of 0.87 days, with no significant growth observed during storage at 4 or 7°C. Consequently, mitigation strategies during dicing and proper refrigeration are essential to minimizing potential health risks associated with diced celery.

Journal of Food Protection®, Number 5, May 2014, pp. 696-863 , pp. 765-771(7)

Kaminski, Chelsea N.1; Davidson, Gordon R.2; Ryser, Elliot T.3

Texas fresh-cut plant shut after links to 5 listeria deaths in celery

Sometime in Jan. 2010, someone in Texas got really sick with listeria.

By mid-May, 2010, five were sick and two were dead – all from the same strain of listeria. By Oct. 20, 2010, five were sick and five had died from the same strain of listeria. Most of the listeriosis patients were elderly with serious underlying health problems, and many were hospitalized before and during the onset of their infection.

Health types said six of the 10 cases were conclusively linked to chopped celery sold by Sangar Fresh Cut Produce of San Antonio, so yesterday, the Texas Department of State Health Services ordered Sangar to stop processing food and recall all products shipped from the plant since January. The order was issued after laboratory tests of chopped celery from the plant indicated the presence of Listeria monocytogenes.

Sangar President Kenneth Sanquist Jr. took issue with the state, adding in a statement,

“The state’s claim that some of our produce now fails to meet health standards directly contradicts independent testing that was conducted on the same products. This independent testing shows our produce to be absolutely safe, and we are aggressively fighting the state’s erroneous findings.”

DSHS inspectors say that in the Sanger plant, they found a condensation leak above a food product area, soil on a preparation table and hand washing issues.

The recalled products – primarily cut fresh produce in sealed packages – were distributed to restaurants and institutional entities, such as hospitals and schools, and are not believed to be sold in grocery stores.

For a glimpse of the Sanger plant, see the video below from Aug. 13, 2010, when Sanquist told KENS5 TV in San Antonio there should be tougher standards in the fresh-cut industry, adding,

"All we’re saying is everyone should have that standard. There is an entire process that we have to follow on a daily basis, if you miss a step or two steps or try to take a short cut…children could get very sick."

Sanquist said many businesses only require their produce company have a recall program in place and that’s simply not enough prevention.

Dirty dozen food warnings are simplistic and suck

It’s end-of-year, so lists are big, and I’m fond of my Top-5 Records label list.

But some are just dumb, and it’s good to see the science types in New Zealand calling out some BS.

The Dominion Post reports tomorrow that toxicologists have accused a food safety campaigner of a lack of understanding after she advised people to eat organic celery to avoid pesticides.

Alison White has ranked celery at the top of a list of foods likely to contain pesticide residue, but scientists say that does not mean indulging in the vegetable will cause any harm.

Ms White, who is a researcher and co-convenor of the Safe Food Campaign, said consumers wanted information about whether their food contained pesticide residues.

Canterbury University toxicology professor Ian Shaw said Ms White’s table, which she published on the group’s website, displayed "naughtiness" in referencing research about cancer risks among people who sprayed vegetables, not those who ate them.

Ms White’s comments also showed she did not understand the difference between how dangerous a chemical was, and the actual chance or risk of it causing any harm.

The Food Safety Authority’s principal toxicology adviser, John Reeve, dismissed Ms White’s suggestion that pesticide residues could be making our food unsafe.

"Alison White and her colleagues have no expertise in toxicology and don’t understand the science."

Dr Reeve said pesticide limits were determined by how much of a chemical growers needed for it to work.

That limit was hundreds of times lower than the levels that would have any impact on human health, he said.