It ain’t happening at retail: Cut cantaloupe needs to be stored at 4C to control Listeria growth

Cantaloupes, marketed as “Rocky Ford,” were implicated in the U.S. multistate outbreak of listeriosis in 2011, which caused multiple fatalities. Listeria monocytogenes can survive on whole cantaloupes and can be transferred to the flesh of melons.

fresh-cut.cantaloupeThe growth of L. monocytogenes on fresh-cut “Athena” and “Rocky Ford” cantaloupe cultivars during refrigerated storage was evaluated. Fresh-cut cubes (16.4 cm3) from field-grown cantaloupes were each inoculated with 5 log10 CFU/mL of a multi-strain mixture of L. monocytogenes and stored at 4°C or 10°C. Inoculated fresh-cut cubes were also: (1) continuously stored at 4°C for 3 days; (2) temperature-abused (TA: 25°C for 4 h) on day 0; or (3) stored at 4°C for 24 h, exposed to TA on day 1, and subsequently stored at 4°C until day 3. L. monocytogenes populations on fresh-cut melons continuously stored at 4°C or 10°C were enumerated on selected days for up to 15 days and after each TA event. Brix values for each cantaloupe variety were determined. L. monocytogenes populations on fresh-cut cantaloupe cubes stored at 4°C increased by 1.0 and 3.0 log10 CFU/cube by day 7 and 15, respectively, whereas those stored at 10°C increased by 3.0 log10 CFU/cube by day 7.

Populations of L. monocytogenes on fresh-cut cantaloupes stored at 10°C were significantly (p < 0.05) greater than those stored at 4°C during the study. L. monocytogenes showed similar growth on fresh-cut “Athena” and “Rocky Ford” cubes, even though “Athena” cubes had significantly higher Brix values than the “Rocky Ford” fruit.

L. monocytogenes populations on fresh-cut cantaloupes exposed to TA on day 1 and then refrigerated were significantly greater (0.74 log10 CFU) than those stored continuously at 4°C for 3 days. Storage at 10°C or exposure to TA events promoted growth of L. monocytogenes on fresh-cut cantaloupe during refrigerated storage.

Survival and growth of Listeria monocytogenes on fresh-cut “Athena” and “Rocky Ford” cantaloupes during storage at 4°C and 10°C

Nyarko Esmond, Kniel Kalmia E., Reynnells Russell, East Cheryl, Handy Eric T., Luo Yaguang, Millner Patricia D., and Sharma Manan. Foodborne Pathogens and Disease. August 2016, ahead of print. doi:10.1089/fpd.2016.2160.

EFSA advises on meat spoilage during storage and transport

Continuing in the advice vein, the European Food Safety Authority is trying to balance safety and quality when transporting meat. had previously advised on the implications for meat safety if two parameters – time and temperature – varied and provided several scenarios for ensuring safety of meat during storage and transport of meat. The Commission subsequently asked EFSA to consider what implications such scenarios would have for the growth of bacteria that cause meat to spoil.

“If the sole consideration was safety, policy makers would have more options on the table to pick from. However, scenarios that are acceptable in terms of safety may not be acceptable in terms of quality,” said Dr. Marta Hugas, Head of EFSA’s Biological Hazards and Contaminants unit.

Current legislation requires that carcasses are chilled to no more than 7C and that this temperature is maintained until mincing. The European Commission wants to revise this legislation to provide industry with more flexibility and asked EFSA’s scientific advice on safety and quality aspects.

Experts also said that effective hygienic measures during slaughter and processing help control contamination with spoilage bacteria.

How do you like them tamales: Variations in storage and reheating procedures

Once made, quickly refrigerate tamales to limit spore growth, and frying may not be the best reheating option. Microwaves are lousy for cooking but great for reheating.

tamalesThis study analyzed the behavior of Clostridium perfringens in individual ingredients and tamales containing different pathogen concentrations upon exposure to different temperatures and methods of cooking, storage, and reheating.

In ground pork, C. perfringens cells were inactivated when exposed to 95°C for 30 min. Three lots of picadillo inoculated with 0, 3, and 5 log CFU/g C. perfringens cells, respectively, were exposed to different storage temperatures. At 20°C, cell counts increased 1 log in all lots, whereas at 8°C, counts decreased by 2 log. Four lots of tamales prepared with picadillo inoculated with 0, 2, 3, and 7 log CFU/g prior to the final cooking step exhibited no surviving cells (91°C for 90, 45, or 35 min). Four lots of tamales were inoculated after cooking with concentrations of 0, 0.6, 4, and 6 log CFU/g of the pathogen and then stored at different temperatures. In these preparations, after 24 h at 20°C, the count increased by 1.4, 1.7, and 1.8 log in the tamales inoculated with 0.6, 4, and 6 log inoculum, respectively. When they were stored at 8°C for 24 h, enumerations decreased to <1, 2.5, and 1.9 log in the tamales inoculated with 0.6, 4, and 6 log of C. perfringens cells, respectively. However, when the lots were exposed to 20°C and then 8°C, 0.8, 1.8, and 2.4 log changes were observed for the tamales inoculated with 0.6, 4, and 6 log, respectively.

how.tamalesMicrowaving, steaming, and frying to reheat tamales inoculated with 6 log CFU/g C. perfringens cells showed that the pathogen was inactivated after 2 min of exposure in the microwave and after 5 min of exposure to steam. In contrast, no inactivation was observed after 5 min of frying. The tamales inoculated with spores (7 log most probable number [MPN]/g) showed a decrease of 2 log after steaming or frying, and no survival was observed after microwaving. Tamales inoculated with spores (7 log MPN/g) after cooking were susceptible to microwaves, but 2.4 and 255 MPN/g remained after frying and steaming, respectively.

Behavior and inactivation of enterotoxin-positive Clostridium perfringens in pork picadillo and tamales filled with pork picadillo under different cooking, storage, and reheating conditions

Journal of Food Protection®, Number 5, May 2016, pp. 696-889, pp. 741-747(7)

Villarruel-López, A.; Ruíz-Quezada, S. L.; Castro-Rosas, J.; Gomez-Aldapa, C. A.; Olea-Rodríguez, M. A.; Nuño, K.; Navarro-Hidalgo, V.; Torres-Vitela, M. R.

33 dead after eating insecticide on sweets in Pakistan

Some 33 people including five children have now died in central Pakistan after eating sweets accidentally tainted with insecticide, officials said Sunday.

pakistansweetsgettyimages-471166594The mass poisoning occurred in the Karor Lal Esan area of Punjab province last month.

“The death toll from poisonous sweets has risen to 33 and 13 other victims are still in hospital,” district police chief Muhammad Ali Zia told AFP.

Local resident Umar Hayat bought the baked confectionery on April 17 to distribute among friends and family to celebrate the birth of his grandson.

Police were investigating how the chemicals were introduced into the sweets preparation process, he said.

Police last week said the worker may have inadvertently added pesticide to the sweet mix since there was a pesticide shop close by which was being renovated, and the owner had left his products at the bakery for safe keeping.

Fish fraud and safety in EU

Deficiencies in food safety controls governing the production and sale of Irish fishery products have been highlighted in an audit by the European Commission’s Food and Veterinary Office.

coffs.harbour.trawlerThe audit, in May, included inspections of two fishing vessels, five landing sites and 11 facilities handling fishery products, as well as meetings with the Food Safety Authority of Ireland and the Sea Fisheries Protection Authority.

Some 296,000 tonnes of fishery products were landed in Ireland in 2012. The audit noted that, between 2012 and 2013, there were six alerts to the international rapid alert system for food and feed involving Irish fishery products. Listeria was found in smoked salmon four times and once in crab, while there was also an alert about parasites in mackerel.

The audit team found that the official control system was not applied consistently.

“The control system presents some gaps with regard to registration/approval of cold stores, inspection of vessels, temperature recording devices, drafting and implementing food safety management systems . . .” it stated.

Cold storage

The audit team found that although two cold stores used for fishery products had been approved by the Department of Agriculture, the approval did not include the storage of fishery products. Also, the approval conditions were not satisfactory because they did not require a temperature of -18 degrees.

The authorities had not inspected some premises handling fishery products as often as stipulated. This was explained by “staff constraints”.

The cold stores and processing establishments inspected were found to have broadly met the hygiene and structural requirements.

“However, one establishment could not be considered compliant with EU requirements. There were structural deficiencies … and it was in a poor state of maintenance,” the report stated.

It found shortcomings in other establishments, such as storing exposed and packaged products in the same room and a lack of temperature-recording devices in some cold stores on vessels.

The audit made six recommendations, including the regular inspection of all fishing vessels.

It said authorities should ensure all food business operators maintained procedures based on HACCP principles and that facilities comply with requirements such as the use of temperature control devices in cold stores before being approved.

Fate of Escherichia coli O157:H7 and Salmonella on whole strawberries and blueberries of two maturities under different storage conditions

Strawberries and blueberries harvested at or near full-ripe maturity tend to be less firm and more susceptible to bruising during harvest and transport. The objective of this research was to determine the fate of Escherichia coli O157:H7 and Salmonella on bruised and intact surfaces of whole strawberries and blueberries at shipping (2°C) and retail display (15.5°C) temperatures.

pick-your-own-strawberriesStrawberries and blueberries were either purchased from a supermarket or were harvested immediately prior to use; they were bruised using established protocols, were spot inoculated, and were incubated at 2 and 15.5°C. Strawberries, subjected to modified atmospheres, were further transferred to bags and were sealed in with an initial atmosphere of ca. 10% CO2 and 5% O2. Strawberries were sampled at 0, 2, 5, and 24 h and on days 3 and 7; blueberries were sampled on days 0, 1, 3, and 7. After stomaching, samples were enumerated on nonselective and selective media, and populations were recorded as log CFU per berry. At both storage temperatures, population declines for both E. coli O157:H7 and Salmonella were seen under all conditions for strawberries. At 2 ± 2°C, E. coli O157:H7 and Salmonella populations on blueberries declined over 7 days under all conditions. At 15.5 ± 2°C, E. coli O157:H7 populations declined; however, Salmonella populations initially declined but increased to populations near or above initial populations over 7 days on blueberries. No overall significant differences were observed between bruised and intact treatments or between the two maturity levels for strawberries and blueberries. Modified atmospheric conditions did not affect the behavior of E. coli O157:H7 and Salmonella on strawberries at both temperatures.

blueberryThis research indicates that E. coli O157:H7 and Salmonella do not grow on strawberries at shipping or retail display temperatures, even when they are harvested at a maturity prone to bruising; however, Salmonella growth may occur on bruised full ripe blueberries under retail display temperatures.

Journal of Food Protection®, Number 7, July 2014, pp. 1052-1240, pp. 1093-1101(9)

Nguyen, Thao P.1; Friedrich, Loretta M.1; Danyluk, Michelle D.2

Abuso de temperature fue uno de los factores causantes del brote de Salmonella del 2008

Traducido por Gonzalo Erdozain

Resumen del folleto informativo mas reciente:

– El brote de Salmonella que enfermó a 1,500 personas en el 2008 fue causado por pimientos
– Platos con tomates y pimientos dejados a temperatura ambiente pueden haber empeorado el brote
– Refrigere platos con tomates a temperaturas iguales o menores a 41°F

Los folletos informativos son creados semanalmente y puestos en restaurantes, tiendas y granjas, y son usados para entrenar y educar a través del mundo.

Si usted quiere proponer un tema o mandar fotos para los folletos, contacte a Ben Chapman a
Puede seguir las historias de los folletos informativos y barfblog en twitter
@benjaminchapman y @barfblog.


Pre-packaged sandwiches stored at wrong temps in Ireland

Almost one in three pre-packed sandwiches are stored or displayed at the wrong temperature, increasing the risk of food poisoning, the Food Safety Authority of Ireland (FSAI) has warned.

The authority has just published a study into the microbiological safety of pre-packed sandwiches. While the findings show that 99% of sandwiches were satisfactory when tested for the foodborne bacteria, Listeria, there was concern over the storage of these food items.

Altogether, 29% of pre-packed sandwiches were being stored or displayed at temperatures higher than five degrees Celsius. Pre-packed sandwiches should be stored at five degrees Celsius or cooler, as this stops or slows down the growth of bacteria.

Meanwhile the study found that four of the five sandwiches, which were classified as unsatisfactory or unacceptable/potentially hazardous, were stored above eight degrees Celsius, with one sandwich displayed unrefrigerated at almost 18 degrees Celsius.

The study involved the testing of 948 pre-packaged sandwiches from retailers and caterers across the country. Sandwiches made to order, unwrapped sandwiches and sandwiches which receive heat-treatment, e.g. toasted sandwiches and paninis. were excluded from study.

Do you feel lucky? Some food good long past expiration date

A new survey sponsored by, a food storage reference website that estimates U.S. consumers unnecessarily discard billions of dollars of food a year, found that three in four U.S. consumers believe certain foods are unsafe to eat after the date on the packaging has passed.

But, according to Andy Miller of, experts say that if most foods are stored properly, they can be safe for days after the ‘use by’ date.

Ira Allen, a Food and Drug Administration spokesman, said the food date does not equate to safety, adding,

“If something is past its date, and stored properly, often it’s OK."

Michael Doyle, director of the University of Georgia’s Center for Food Safety, said foods that can last far beyond an expiration date with proper storage include flour, sugar, rice and cake mixes, adding.

“There’s no reason that dry goods wouldn’t be safe except if it becomes wet.’’

Waste not, want not: food safety, discarding food, and tough times

Whenever I think of leftover pizza, I recall my teenage years listening to Rolling Stones on vinyl at George’s apartment, I wonder whatever happened to that stray puppy one of the visitors brought home until the fleas were discovered, and I wonder how long the pizza would be good. I’ve probably eaten pieces of pizza that spent the night on the turntable.

So when Susan Reef, president of US Food Safety Corp., says eating pizza that has spent a few hours at room temperature is a no-no, I sorta scoff (low water activity, no epidemiological history of outbreaks from morning-after pizza consumption, she probably doesn’t like the Stones).

Kim Painter reports in USA Today tomorrow that if Maribel Alonso, a food safety specialist at the U.S. Department of Agriculture’s Meat and Poultry Hotline, brings home a broken egg, she discards it.

Doug Powell, a food safety person at Kansas State University, says he would cook with the egg, probably into a batch of pancakes, adding,

"It’s just messy, but if it’s been kept cold, it should be OK.”

(Messy means, be careful of cross-contamination).