Listeria is back in the news thanks to yet another food safety crisis sweeping Europe, this time on Hungarian-sourced frozen vegetables that have also arrived in Italy.
Listeria monocytogenes, the bacterium
La
Listeria monocytogenes
is a potentially very dangerous pathogenic bacterium for both humans and animals. The danger is serious to the health of the most vulnerable consumer groups.
The acronym YOPI, is to identify those at risk, which are preschool children (
Y
oung), the elderly (
O
ld), pregnant women (
P
regnant) and the immuno-depressed (
I
mmunocompromised). Weakness of the immune system, which is physiological in the first three categories (children, the elderly, pregnant women) and pathological in the last (also due to drug treatments, e.g., chemotherapy), exposes such individuals to a real risk of failing to fight off Listeria infection.
In YOPI subjects,
L.
monocytogenes
can cause severe illness, with frequent central nervous system involvement and abortion in pregnant women (invasive listeriosis). In less severe cases, infections cause gastrointestinal complaints accompanied by fever. Which can occur even in people with strong baseline immunity (non-invasive listeriosis).
Listeriosis-according to the most recent data published by EFSA (2017)-ranks fifth among reported zoonoses in Europe. With 2,536 cases reported in 2016 (0.47 cases per 100,000 population) and a 9% increase over 2015. Mortality is mainly seen among the elderly, particularly those above 84 years of age. (1)
Listeria, where it is found and how to eliminate it
Listeria food poisoning is an ‘old’ problem that has periodically plagued the food industry since the 1980s. In fact, Listeria monocytogenes can contaminate raw materials, such as milk produced by animals with mastitis or intestinal carriers of the bacterium, meat during slaughter, or vegetables before harvesting.
Much of the contamination therefore occurs in food processing plants, as listeria has great environmental survivability and can persist in equipment, tools, cold rooms, food preparation and storage rooms. All the more so in that self-control procedures (GHP, GMP, HACCP) are not adopted and effectively executed with due diligence.
Listeria monocytogenes resists freezing very well and can multiply at refrigeration temperatures between +2 and +4°C. Conversely, the bacterium is rapidly inactivated above 70°C, so it can be destroyed through cooking and/or and pasteurization (e.g., milk) of foods.
Listeria, the case of frozen vegetables ‘Made in Hungary‘
The recent food safety crisis related to listeria contamination of frozen vegetables originates from a single manufacturing company based in Hungary.
However, the outbreak of invasive listeriosis due to consumption of frozen corn-and perhaps other vegetables, such as spinach and green beans-has been slow-moving. From 2015 to 2018 in Austria, Denmark, Finland, Sweden and Great Britain. Causing at least 47 diseases, with 9 deaths (mortality rate 19%).
Sequencing of the genome of the bacterium(L. monocytogenes serogroup IVb, sequence type ST6), isolated from patients and from vegetables produced by the Hungarian company, established a definite epidemiological link between the intake of the uncooked frozen vegetables and the disease.
Thus, the primary responsibility falls on the operator who processed the vegetables. Indeed, analysis confirmed persistent L. monocytogenes IVb, ST6 contamination of its production lines. (1)
However, the responsibility is reaffirmed competitor of all downstream players in the supply chain. Under the banner of globalized savings at any cost, the foreign retail and discount store giants such as Lidl, Tesco, Aldi, Waitrose, Sainsbury have in turn used the ‘frozen vegetables to listeria’,(2) thus contributing to the spread of the crisis.
Final reflections
Once again, we are faced with a crisis that could have been predicted, prevented and avoided. And it may be repeated instead, until the European Commission decides to impose an appropriate penalty regime instead of relegating to the ‘
knowledge centers
‘
the treatment of the topic ‘
food safety
‘.
The question remains.
whether effective knowledge of the origin of the primary ingredient–by the consumer–can foster purchasing choices that prioritize not only quality, but also food safety.
From theory to practice, the Italian food supply chain is subject to sanitation controls of an intensity and frequency not comparable to those in use by other member countries. (3) So how many would choose ‘traditional Findus minestrone‘ – as an alternative to similar Orogel product, or Rolli – if they knew that only the former is made from Central European raw materials?
Silvia Bonardi and Dario Dongo
Notes
(1) For more information, see EFSA and ECDC, 2018.
Multi-country outbreak of Listeria monocytogenes serogroup IVb, multi-locus sequence type 6, infections linked to frozen corn and possibly to other frozen
vegetables – first update
(2) For good memory, it is worth mentioning that the same international retail giants were also involved in the giant scandal of horse meat presented as beef(Horsegate). Impunity causes recidivism
(3) This finding has no parochial pretensions, relying instead on the analysis of standards and their application. For more details, see the free ebook ‘
‘Food safety, mandatory rules and voluntary standards.
‘, at
https://www.greatitalianfoodtrade.it/libri/sicurezza-alimentare-regole-cogenti-e-norme-volontarie-il-nuovo-libro-di-dario-dongo
Graduated in Veterinary Medicine and Specialist in Inspection of Food of Animal Origin and in Veterinary Public Health, she is Professor of Inspection and Control of Food of Animal Origin at the University of Parma.
Dario Dongo, lawyer and journalist, PhD in international food law, founder of WIISE (FARE - GIFT - Food Times) and Égalité.
