Rockmelon safety hard to grasp

Contrary to what Australians are being told, cantaloupe – er, rockmelon – is a known source of foodborne illness and many scientists have investigated the many ways nasty bacteria get on or in the melon; along with potential treatments.

red.dirt.melonsIn this paper, researchers from the U.S. Department of Agriculture report surface structure and biochemical characteristics of bacteria and produce play a major role in how and where bacteria attach, complicating decontamination treatments.

Whole cantaloupe rind surfaces were inoculated with Salmonella, Escherichia coli O157:H7, and Listeria monocytogenes at 107 CFU/ml. Average population size of Salmonella, Escherichia coli O157:H7, and L. monocytogenes recovered after surface inoculation was 4.8 ± 0.12, 5.1 ± 0.14, and 3.6 ± 0.13 log CFU/cm2, respectively. Inoculated melons were stored at 5 and 22°C for 7 days before washing treatment interventions. Intervention treatments used were (i) water (H2O) at 22°C, (ii) H2O at 80°C, (iii) 3% hydrogen peroxide (H2O2) at 22°C, and (iv) a combination of 3% H2O2 and H2O at 80°C for 300 s. The strength of pathogen attachment (SR value) at days 0, 3, and 7 of storage was determined, and then the efficacy of the intervention treatments to detach, kill, and reduce transfer of bacteria to fresh-cut pieces during fresh-cut preparation was investigated. Populations of E. coliO157:H7 attached to the rind surface at significantly higher levels (P < 0.05) than Salmonella and L. monocytogenes, but Salmonella exhibited the strongest attachment (SR value) at all days tested. Washing with 3% H2O2 alone led to significant reduction (P < 0.05) of bacteria and caused some changes in bacterial cell morphology. A combination treatment with H2O and 3% H2O2 at 8°C led to an average 4-log reduction of bacterial pathogens, and no bacterial pathogens were detected in fresh-cut pieces prepared from this combination treatment, including enriched fresh-cut samples.

The results of this study indicate that the microbial safety of fresh-cut pieces from treated cantaloupes was improved at day 6 of storage at 5°C and day 3 of storage at 10°C.

Effect of hydrogen peroxide in combination with minimal thermal treatment for reducing bacterial populations on cantaloupe rind surfaces and transfer to fresh cut pieces


Ukuku, Dike O.1; Mukhopadhyay, Sudarsan2; Geveke, David2; Olanya, Modesto2; Niemira, Brendan2

1: U.S. Department of Agriculture, Agricultural Research Service, Eastern Regional Research Center, 600 East Mermaid Lane, Wyndmoor, Pennsylvania 19038, USA;, Email: 2: U.S. Department of Agriculture, Agricultural Research Service, Eastern Regional Research Center, 600 East Mermaid Lane, Wyndmoor, Pennsylvania 19038, USA

Journal of Food Protection, August 2016, Number 8, Pages 1316-1324, DOI:

Food fraud: EU warns Italy to stop treating squid with hydrogen peroxide

Michael Ramsingh of reports European trade officials have warned Italy to stop soaking its squid in hydrogen peroxide (H2O2) and shipping it to markets around the EU.

squid-fish-marketItalian officials were notified by the EU Commission’s Ministry of Health that soaking squid in H2O2 currently violates specific food safety regulations.  The practice is legal in the Italian market but is not approved in other member countries.

“The use of this substance as a food additive, therefore, is not authorized in the EU,” the Commission said in a statement. “The Member States have the responsibility to enforce effectively the Union legislation concerning the food chain, which also includes rules applicable to the use of food additives.”

H2O2 is used to treat squid to increase its marketability since it whitens the product on display. The treatment does not pose a health risk for consumers. However, the practice is considered dubious since it is nearly impossible to tell a treated squid product with a non-treated item, which makes it difficult to verify the actual freshness of the item.