Effect of acid adaptation and acid shock on thermal tolerance and survival of Escherichia coli O157:H7 and O111 in apple juice

Posted on October 7, 2014 by Douglas Powell

Gradual exposure to moderate acidic environments may enhance the thermal tolerance and survival of Escherichia coli O157:H7 in acid and acidified foods. Limited studies comparing methodologies to induce this phenomenon have been performed.

The effects of strain and physiological state on thermal tolerance and survival of E. coli in apple juice were studied. The decimal reduction time (D-value) at 56°C [D 56° C] was determined for E. coli O157:H7 strains C7927 and ATCC 43895 and E. coli O111 at four physiological states: unadapted, acid-shocked (two methodologies used), and acid-adapted cells. The effect of acidulant was also evaluated by determining the D 56° C for the O157:H7 strains subjected to acid shock during 18 h in Trypticase soy broth (TSB), with pH 5 adjusted with hydrochloric, lactic, and malic acids. Survival of the three strains at four physiological states was determined at 1 ± 1°C and 24 ± 2°C.

Experiments were performed in triplicate. For thermal inactivation, a significant interaction was found between strain and physiological state (P < 0.0001). Highest thermal tolerance was observed for the 43895 strain subjected to acid shock during 18 h in TSB acidified with HCl (D 56° C of 3.0 ± 0.1 min) and the lowest for the acid-shocked C7927 strain treated for 4 h in TSB acidified with HCl (D 56° C of 0.45 ± 0.06 min). Acidulants did not alter the heat tolerance of strain C7927 (D 56° C of 1.9 ± 0.1 min; P > 0.05) but significantly affected strain 43895 (P < 0.05), showing the greatest tolerance when malic acid was used (D 56° C of 3.7 ± 0.3 min).

A significant interaction between strain, storage temperature, and physiological state was noted during the survival experiments (P < 0.05). E. coli O111 was the most resistant strain, surviving 6 and 23 days at 24 and 1°C, respectively. Our findings may assist in designing challenge studies for juices and other pH-controlled products, where Shiga toxin–producing E. coli represents the pathogen of concern.

Journal of Food Protection®, Number 10, October 2014, pp. 1656-1833, pp. 1656-1663(8)

Usaga, Jessie, Worobo, Randy W., Padilla-Zakour, Olga I.

http://www.ingentaconnect.com/content/iafp/jfp/2014/00000077/00000010/art00001

Shigellosis or sunstroke?

Posted on September 11, 2014 by Ben Chapman

This one time, when I was working at a greenhouse as a summer student, I called in sick and told the boss I had sunstroke (from working outside the previous day).

And then I went to a free lunch-time Red Hot Chili Peppers concert on Yonge St (that’s in Toronto, which is in Canada). I’ve matured since then.

According to the UK Mirror a per 250 Brits who visited a resort in Egypt were told by management that they were suffering from sunstroke – but it was actually shigellosis.

The Mirror revealed last month how First Choice customers caught the bug, thought to be shigella, at Coral Sea Waterworld, Sharm el Sheikh.

Victim Tracy Roscoe, 51, said she got a letter two days before she and her family were due to leave after spending most of the trip laid up.

“It stinks,” said Mrs Roscoe. “They tried to blame the sun when they knew it was a bug doing the rounds in the hotel.”

The letter – “Sunstroke And How To Stay Healthy” – referred to heat above 40C and how over-exposure and low fluids can cause sunstroke.

But many sick guests complained of poor food hygiene by staff.

Nick Harris of lawyers Simpson Millar – handling claims from 250 of them – said: “It’s outrageous if there was an attempt to intimate to customers that the massive sickness outbreak was caused by sunstroke, which is what the letter seems to imply.”

Fancy food ain’t safe food: California vegan True Food Kitchen edition

Posted on September 7, 2014 by Douglas Powell

An upscale restaurant at Fashion Island, California, that bills itself as a healthy living establishment is at the center of a suspected foodborne illness outbreak involving at least six victims, county officials said Thursday.

The sickened diners tested positive for shigella, an intestinal bacteria that triggers severe diarrhea. The “common factor” for each victim was they ate a meal at True Food Kitchen in Newport Beach on Aug. 21, 23, 24 and 25, county healthy officials said.

The county shut the restaurant Aug. 28 to investigate the outbreak. None of the victims ate the same dish, leading investigators to believe that the bacteria was spread “person to person,” said Denise Fennessy, director of Environmental Health at the county’s Health Care Agency.

“There was no common food item to focus on,” she said.

Though the case is still under investigation, True Food was allowed to reopen Saturday night after meeting certain criteria, including sanitizing the entire restaurant and bringing in replacement staff, Fennessy said.

Anita Walker, vice president of marketing for parent company Fox Restaurant Concepts in Arizona, said the “health and safety of our guests and employees are our first priority.”

150 suffer Shigella poisoning in Jordan

Posted on August 12, 2014 by Douglas Powell

The Ministry of Health has dealt with over 150 cases of food poisoning in a recent incident in the Shihabieh area in Karak, 140km south of the capital, a Health Ministry official said on Monday.

Bashir Qasir, head of the ministry’s communicable diseases department, said the results of an analysis of stool samples taken from the patients proved the presence of Shigella bacteria.

Samples taken from a popular restaurant in the area that serves hummus, and stool samples from restaurant workers also point to the presence of Shigella bacteria.

“The ministry’s health team took precautions by closing the suspected restaurant on Saturday morning until the results of the samples taken from there are fully tested,” Qasir told The Jordan Times over the phone, noting that tests of the food samples are not fully conclusive.

The official said the poisoning is not related to water pollution.

Shigella leaves 100 British tourists sick in Egypt resort

Posted on August 4, 2014 by Douglas Powell

Up to 100 British tourists have fallen ill after a sickness bug swept through an Egyptian holiday resort.

Several were still on intravenous drips in their hotel rooms last night at the four-star Coral Sea Waterworld complex.

Angry holidaymakers blamed the virulent bug on dirty buffet food containers, utensils and tables and poor hygiene.

It has spread so fast that resort bosses have had to draft in extra doctors to cope with the sickness outbreak.

Legal firm Simpson Millar, acting for holidaymakers staying at the hotel, say they have already had 50 cases of illness reported to them in the last 24 hours alone.

Lawyer Nick Harris said: “I have been inundated with people contacting me about ruined holidays. Some of the reports I have heard are horrific.

“Bedridden families with intravenous drips in their arms and taking it in turns to be sick and use the toilet. We strongly suspect it’s a bacterial poisoning. It looks like up to 100 Brits are affected.

“They have spent the majority of their stay confined to their bedrooms and many of them on IV drips”.

Staff have been kitted out with latex gloves and hand sanitisers to try and stem the spread of infection.

Victims have been diagnosed with Shigella – a bug commonly associated with food poisoning and poor hygiene.

It is closely related to salmonella, which doctors in the resort have also been testing for.

Angry tourists have posting about their ordeal on travel site TripAdvisor.

Food safety culture? Walmart restaurant linked to Shigella outbreak ready to reopen

Posted on July 16, 2014 by Douglas Powell

Salsarita’s Restaurant in the Walmart Home Office Café will reopen Wednesday following a Shigella outbreak that made hundreds sick.

The email said Eurest, the third-party company in charge of managing the kitchen, will hire a quality assurance manager and will retrain staff on the company’s safety protocols.

Shigella outbreak in Arkansas linked to Walmart?

Posted on June 24, 2014 by Douglas Powell

The Salsarita’s Restaurant at the Walmart Home Office Cafe in Bentonville is closed while the Arkansas Health Department works to figure out how people got sick with Shigella.

According to health department conducted an inspection last Wednesday right after people started getting sick.

Inspectors found nine violations on that inspection.

Of those nine violations, five were marked priority, meaning they were concerns that needed to be fixed fast.

Some violations included, employees not washing their hands or touching cooked food without wearing gloves.

The report said raw chicken had been dripping on bottled drinks.

A second inspection was done Monday. Inspectors found seven violations, some of them are the same.

The follow-up report said employees were out of the kitchen’s service containers and are still not washing their hands enough.

Eurest, the company responsible for managing the Home Office Cafe, said they are continuing to work with the health department and Walmart to figure out how the sickness spread.

Antibacterial soaps can reduce risk of foodborne illness

Posted on April 16, 2014 by Douglas Powell

Friend of the blog Don Schaffner has published some new research that shows the use of antibacterial soaps can reduce the spread of harmful bacteria – that often leads to foodborne illness – more effectively than using non-antibacterial soaps.

The research, published in the peer-reviewed Journal of Food Protection (Vol. 77, No. 4, 2014, pp. 574-582), used new laboratory data, together with simulation techniques, to compare the ability of non-antibacterial and antibacterial products to reduce the risk of the infectious disease shigellosis, which is often spread during food preparation.

Lead researcher Donald Schaffner of Rutgers University’s Department of Food Science says the data show that the use of three antibacterial wash products result in a statistically significant reduction in the presence of Shigella (the bacterium that causes shigellosis) compared to the use of the non-antibacterial soaps.

“This exciting research blends quantitative microbial risk assessments with an impressive set of laboratory data to show that antibacterial treatments are more effective than non-antibacterial treatments in reducing disease,” said Dr. Schaffner.

In the study, 163 subjects were used to compare two non-antibacterial products and three antibacterial products, with a study design intended to simulate food handling. The participants’ hands were exposed to Shigella and then treated with one of the five products before handling food melon balls. The resulting levels of Shigella on the food were then measured.

The levels of Shigella were then used to predict the outcome from an event in which 100 people would be exposed to Shigella from melon balls that had been handled by food workers with Shigella on their hands.

The data show all three antibacterial treatments significantly lowered the concentration of Shigella compared to the non-antibacterial treatments. Based on this model, the paper predicted that by washing with the antibacterial treatments, the number of illnesses could be reduced tenfold.

“This research provides strong evidence that antibacterial soaps are significantly more effective than non-antibacterial soaps in reducing Shigella on the hands and its subsequent transfer to ready-to-eat foods,” the authors write.

The American Cleaning Institute (www.cleaninginstitute.org) and the Personal Care Products Council (www.personalcarecouncil.org) provided funding for the research as part of the groups’ ongoing commitment to product and scientific stewardship to affirm the safety and benefits of these products.

An abstract summarizing the paper, “Quantitative Microbial Risk Assessment of Antibacterial Hand Hygiene Products on Risk of Shigellosis,” can be found online athttp://www.ingentaconnect.com/content/iafp/jfp/2014/00000077/00000004/art00006#aff_3

46 sickened; Shigella outbreak traced to imported basil in Norway, 2011

Posted on December 18, 2013 by Douglas Powell

While the U.S. extends a comment period for something about improving spice safety (raw herbs have been a known food safety risk for decades), Norway reports on a 2011 outbreak of Shigella sonnei linked to basil that sickened at least 46 people updating previous reports.

On 9 October 2011, the University Hospital of North Norway alerted the Norwegian Institute of Public Health (NIPH) about an increase in Shigella sonnei infections in Tromsø. The isolates had an identical ‘multilocus variable-number tandem repeat analysis’ (MLVA) profile. Most cases had consumed food provided by delicatessen X. On 14 October, new S. sonnei cases with the same MLVA-profile were reported from Sarpsborg, south-eastern Norway. An outbreak investigation was started to identify the source and prevent further cases. All laboratory-confirmed cases from both clusters were attempted to be interviewed.

In addition, a cohort study was performed among the attendees of a banquet in Tromsø where food from delicatessen X had been served and where some people had reported being ill. A trace-back investigation was initiated. In total, 46 cases were confirmed (Tromsø= 42; Sarpsborg= 4). Having eaten basil pesto sauce or fish soup at the banquet in Tromsø were independent risk factors for disease. Basil pesto was the only common food item that had been consumed by confirmed cases occurring in Tromsø and Sarpsborg. The basil had been imported and delivered to both municipalities by the same supplier. No basil from the specific batch was left on the Norwegian market when it was identified as the likely source. As a result of the multidisciplinary investigation, which helped to identify the source, the Norwegian Food Safety Authority, together with NIPH, planned to develop recommendations for food providers on how to handle fresh plant produce prior to consumption.

Food companies not allowed to sue Ottawa over mistaken recalls, B.C. court rules

Posted on February 5, 2013 by Douglas Powell

On Aug. 17, 2007, the Canadian Food Inspection Agency issued two warnings about LA Salad baby carrots sold at Costco because they may have been contaminated with Shigella. The Agency said at the time that the carrots had already made four people sick, which triggered a subsequent recall in the United States.

The company responded by saying CFIA’s allegations weren’t supported by scientific fact and accused them of shoddy testing. In documents filed in B.C. Supreme Court, the company claimed damages due to a continued loss of business.

Six years later, a B.C. court ruled that it and other such companies cannot sue the federal government over mistaken recalls, saying CFIA inspectors owe a legal duty to the public, not the food producers they might wrongly accuse.

The National Post reports that with regulators more often criticized for failing to keep on top of foodborne illness, the case offers a rare view from the other side: producers who, deservedly or not, suffer hugely from public alerts.

If they don’t face any liability ever, they can make mistakes and never find out which food product was actually making people sick

The food-inspection agency should be held accountable in court when it points the finger at the wrong culprit, if only to ensure the real sources of outbreaks are uncovered, said Dale Sanderson, L.A. Salad’s Vancouver lawyer.

“If they don’t face any liability ever, they can make mistakes and never find out which food product was actually making people sick,” said Mr. Sanderson. “There should be an incentive to do a really good job. … I can’t believe the CFIA won’t recall food because they might get sued.”

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