mardi 28 février 2017

Semi-dried tomatoes and foodborne virus

In February 2017, RASFF (Rapid Alert System for Food and Feed) published an alert implicating semi-dried tomatoes contaminated with norovirus. Originating from Italy, semi-dried tomatoes in sunflower oil were delivered to the Czech Republic who detected foodborne viruses (Norovirus). Both genogroups GI and GII, according to the report, were found in the samples tested.

This is unfortunately not the first time that Foodborne Viruses are to be found in Semi-dried tomatoes :

England, 2011

In October 2011, two primary cases of hepatitis A virus (HAV) infection with identical HAV genotype IB strains to those seen in other outbreaks associated with semi-dried tomatoes were reported in England. Both cases had consumed semi-dried tomatoes. Epidemiological investigations revealed 2 additional cases of genotype IB strains with different sequences who also reported having consumed semi-dried tomatoes. In November, 5 cases of HAV infection with closely related strains were identified in the Netherlands.

Netherlands, 2010

Between 31 December 2009 and 10 February 2010, 13 patients were infected by an identical hepatitis A virus strain not previously detected in the Netherlands. They had not been abroad and were widely distributed over the Netherlands. A case-control study including 12 cases and 44 controls identified semi-dried tomatoes in oil as the source of the outbreak.

France, 2010

In January 2010, two clusters of nontraveler-associated hepatitis A were reported in 3 districts of southwestern France. A single IB strain of hepatitis A virus (HAV) was isolated. An investigation was conducted to describe the outbreak, identify the vehicle of transmission and source of infection, and propose appropriate control measures. Twenty-four (51%) reported eating semidried tomatoes, 20 of 566m reported purchasing semidried tomatoes in 1 of 3 different sandwich shop chains.

Australia, 2009

A large outbreak of hepatitis A affected individuals in several Australian states in 2009. Two peaks of infection occurred, with surveillance data suggesting locally acquired infections from a widely distributed food product. The results of both case-control studies and food testing implicated the novel vehicle of semidried tomatoes as the cause of this hepatitis A outbreak. Hepatitis A RNA was detected in 22 samples of semidried tomatoes. Hepatitis A virus genotype IB was identified in 144 of 153 (94%) patients tested from 2009, and partial sequence analysis showed complete identity with an isolate found in a sample of semidried tomatoes.

Production of semi-dried tomatoes

Oven dried

Sun dried

Prevention and control of Foodborne Virus in ready-to-eat semi-dried products

Manufacturers should consider enteric viruses as a major public health risk in their Hazard Analysis and Critical Control Point (HACCP) plans, says FAO. 

Recommendations on prevention and control of HAV 

In addition to safety regulations already in place, measures need to be taken to ensure provision of virus-safe foods in order to prevent contamination. Considering the high prevalence of foodborne infections by viruses, one should exercise precaution. Proper hand hygiene should be maintained, personally and during food preparation, to prevent contamination of food and spread to other persons. Once contamination of foods has occurred, the following mitigation strategies can be employed: (i) disposal of contaminated foods; or (ii) heat treatment (at ≥ 90° C for ≥ 90 seconds and pasteurization at ≥70° C for ≥ 15 minutes). Learn More from FAO.

Persistance and eliminination of Norovirus

NoV & HAV, major vectors of food contamination 

Microbiological hazards associated with fresh produce

Viruses are not likely to grow on contaminated vegetables and fruits but can survive long enough to cause life-threatening illness in humans. Consumption of fresh and lightly processed produce, coupled with an increase in importation of produce from regions where standards for growing and handling produce may be compromised should be an incentive to producers, importers to better monitor this viral risk.

Sources:

Learn more about Food- and Water-borne viruses :

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