Functional Perspective of Leeks: Active Components, Health Benefits and Action Mechanisms

Leek (Allium fistulosum L.), a common and widely used food ingredient, is a traditional medicine used in Asia to treat a variety of diseases. Leeks contain a variety of bioactive substances, including sulfur compounds, dietary fiber, steroid compounds and flavonoid compounds. Many studies have shown that these active ingredients produce the following effects: promotion of blood circulation, lowering of cholesterol, relief of fatigue, anti-inflammation, anti-bacteria, regulation of cell metabolism, anti-cancer, anti-oxidation, and the lowering of fat and blood sugar levels. In this paper, the main bioactive components and biological functions of leeks were systemically reviewed, and the action mechanisms of bioactive components were discussed. As a common food, the health benefits of leeks are not well known, and there is no systematic summary of leek investigations. In light of this, it is valuable to review the recent progress and provide reference to investigators in the field, which will promote future applications and investigations of leeks.

Modification of the existing maximum residue levels for metazachlor in leeks and honey

In accordance with Article 6 of Regulation (EC) No 396/2005, the applicant BASF SE submitted a request to the competent national authority in the Netherlands to modify the existing maximum residue levels (MRLs) for the active substance metazachlor in leeks and honey. The data submitted in support of the request were found to be sufficient to derive MRL proposals. Adequate analytical methods for enforcement are available to control the residues of metazachlor metabolites 479 M04, 479 M08 and 479 M16 in plant matrices and honey at the validated limit of quantification (LOQ) of 0.01 and 0.02 mg/kg for each analyte. Based on the risk assessment results, EFSA concluded that the short-term and long-term intake of residues resulting from the use of metazachlor according to the reported agricultural practice is unlikely to present a risk to consumer health.

Modification of the existing maximum residue levels in leeks and spring onions/green onions/Welsh onions resulting from the use of potassium phosphonates

In accordance with Article 6 of Regulation (EC) No 396/2005, the applicant BASF Agro B.V. Arnhem (NL) Freienbach Branch submitted a request to the competent national authority in the Netherlands to modify the existing maximum residue levels (MRLs) for the active substance potassium phosphonates in leeks and spring onions/green onions/Welsh onions. The data submitted in support of the request were found to be sufficient to derive MRL proposals for the commodities under assessment. Adequate analytical methods for enforcement are available to control the residues of potassium phosphonates in accordance with the proposed residue definition 'phosphonic acid and its salts expressed as phosphonic acid' on the commodities under consideration. Based on the risk assessment results and assuming that the exiting MRLs will be amended as proposed by EFSA in previous outputs, EFSA concluded that the long-term intake of residues resulting from the use of potassium phosphonates according to the reported agricultural practices is unlikely to present a risk to consumer health. Considering the toxicological profile of the active substance, a short-term dietary risk assessment was not required. The risk assessment shall be regarded as indicative because some MRL proposals derived by EFSA in the framework of the MRL review according to Articles 12 and 43 of Regulation (EC) No 396/2005 require further consideration by risk managers.

Modification of the existing maximum residue levels for pendimethalin in peas (with pods), beans (with pods) and leeks

In accordance with Article 6 of Regulation (EC) No 396/2005, the applicant BASF Agro B.V. submitted a request to the competent national authority in France to modify the existing maximum residue levels (MRLs) for the active substance pendimethalin in peas (with pods), beans (with pods) and leeks. The data submitted in support of the request were found to be sufficient to derive MRL proposals for the commodities under assessment. Adequate analytical methods for enforcement are available to control the residues of pendimethalin on the commodities under consideration at the validated LOQ of 0.01 mg/kg. Based on the risk assessment results, EFSA concluded that the short-term and long-term intake of residues resulting from the use of pendimethalin according to the reported agricultural practices is unlikely to present a risk to consumer health.

Modification of the existing maximum residue levels for benzovindiflupyr in leeks and spring onions/green onions/Welsh onions

In accordance with Article 6 of Regulation (EC) No 396/2005, the applicant Syngenta Crop Protection AG submitted a request to the competent national authority in France to modify the existing maximum residue levels (MRLs) for the active substance benzovindiflupyr in leeks and spring onions, green onions and Welsh onions. The data submitted in support of the request were found to be sufficient to derive MRL proposals for the crops under assessment. Adequate analytical methods for enforcement are available to control the residues of benzovindiflupyr on the commodities under consideration at the validated limit of quantification (LOQ) of 0.01 mg/kg. Based on the risk assessment results, EFSA concluded that the short-term and long-term intake of residues resulting from the use of benzovindiflupyr according to the reported agricultural practices is unlikely to present a risk to consumer health.

Modification of the existing maximum residue levels for spirotetramat in leeks, spring onions and honey

In accordance with Article 6 of Regulation (EC) No 396/2005, the applicant Bayer S.A.S. - Crop Science division submitted a request to the competent national authority in Austria to modify the existing maximum residue levels (MRLs) for the active substance spirotetramat in leeks, spring onions and in honey. The data submitted in support of the request were found to be sufficient to derive MRL proposals for all these crops and honey. Adequate analytical methods for enforcement are available to control the residues of spirotetramat and its metabolites in plant matrices on the commodities under consideration and in honey at the validated limit of quantification (LOQ) of 0.01 mg/kg for each analyte. Based on the risk assessment results, EFSA concluded that the short-term and long-term intake of residues resulting from the use of spirotetramat according to the reported agricultural practices is unlikely to present a risk to consumer health.

Outbreak of Clostridium perfringens food poisoning linked to leeks in cheese sauce: an unusual source

Between 11-13 December 2018, local public health authorities in the West Midlands, England were alerted to 34 reports of diarrhoea with abdominal cramps. Symptom onset was ~10 h after diners ate Christmas meals at a restaurant between 7-9 December 2018. A retrospective case-control study, environmental and microbiological investigations were undertaken to determine the source and control the outbreak. An analytical study was undertaken with odds ratios (OR) and 95% confidence intervals (CI). Forty persons were recruited to the analytical study (28/40 cases). Multivariable analysis found that leeks in cheese sauce was the only item associated with illness (aOR 51.1; 95% CI 4.13-2492.1). Environmental investigations identified significant lapses in food safety, including lapses in temperature control during cooking and hot holding, likely cross-contamination between raw and cooked foods and the reuse of leftover cheese sauce for the next day's service. No food samples were taken during the exposure period. Two faecal samples were positive for Clostridium perfringens with one confirming the enterotoxigenic gene. Cheese sauce is an unusual vehicle for the organism and the first time this has been reported in England.

Modification of the existing maximum residue levels for clopyralid in spring/green/Welsh onions and leeks

In accordance with Article 6 of Regulation (EC) No 396/2005, the Agriculture and Horticulture Development Board (AHDB) submitted a request to the competent national authority in the United Kingdom, to modify the existing maximum residue levels (MRL) for the active substance clopyralid in spring onions and leeks. The data submitted in support of the request were found to be sufficient to derive MRL proposals for spring onions/green onions and Welsh onions and for leeks based on the residue definition for enforcement in Regulation (EC) No 396/2005. An adequate analytical method for enforcement is available to control the residues on the commodities under consideration at the validated limit of quantification (LOQ) of 0.01 mg/kg. Based on the available information, EFSA concluded that the long-term intake of residues resulting from the use of clopyralid according to the reported agricultural practices is unlikely to present a risk to consumer health. The reliable end points, appropriate for use in regulatory risk assessment, are presented.

Setting of a maximum residue level for cyantraniliprole in leeks

In accordance with Article 53 of Regulation (EC) 1107/2009, the United Kingdom granted a 120-day emergency authorisation for the use of cyantraniliprole in leek. In order to accommodate for the new use, the Agriculture & Horticulture Development Board submitted an application to raise the existing maximum residue level (MRL) for the crop concerned. The United Kingdom, as evaluating Member State, summarised the data provided by the applicant in an evaluation report which was submitted to the European Commission and forwarded to EFSA. Sufficient residue trials are available to derive an MRL proposal of 0.6 mg/kg for leeks in accordance with the emergency authorised good agricultural practice (GAP). Adequate analytical methods for enforcement are available to control the residues of cyantraniliprole in the commodities under consideration. Based on the risk assessment results, EFSA concluded that intake of residues resulting from the use of cyantraniliprole according to the reported agricultural practice is unlikely to present a risk to consumer health.