Assessment of the virulence of clinical and food isolates of <i>L</i>. <i>monocytogenes</i>.

<p>Parallel testing of the clinical isolates of <i>L</i>. <i>monocytogenes</i> (A) LS660 (designated with gray square) and food pairs isolated from chicken salad LS661 (designated with black square) and celery (□), (B) LS414 (designated with black square) and food pair isolated from coleslaw LS413 (designated with white square), (C) LS412 (designated with black square) and food pair isolated from cheese LS411 (designated with white square) at the doses of 10⁴, 10⁵ and 10⁶ CFU/larva, a > b (P<0.05).</p

LT₅₀ of <i>G</i>. <i>mellonella</i> larvae after inoculation with <i>L</i>. <i>monocytogenes</i> isolates^* related to the major listeriosis outbreaks^**.

<p>LT₅₀ of <i>G</i>. <i>mellonella</i> larvae after inoculation with <i>L</i>. <i>monocytogenes</i> isolates^{<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0184557#t004fn001" target="_blank">*</a>} related to the major listeriosis outbreaks^{<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0184557#t004fn002" target="_blank">**</a>}.</p

<i>L</i>. <i>monocytogenes</i> isogenic mutants with deletion in <i>inlA</i>, <i>inlB</i> and <i>inlAB</i> in <i>Galleria</i>.

<p>Mortality of larvae infected with the wild type <i>L</i>. <i>monocytogenes</i> strain LS1209 (designated with black square) and isogenic mutants with deletion in <i>inlB</i> LS1214 (designated with white square), <i>inlAB</i> LS 1215 (designated with light gray square) and <i>inlA</i> LS1222 (designated with dark gray square) at the doses of (A) 10⁶ CFU/larva (B) 10⁵ CFU/larva, (C) 10⁴ CFU/larva, a > b (P<0.05). Presented results are average of three independent trials.</p

Comparison between wild type <i>L</i>. <i>monocytogenes</i> and deletion mutants in <i>virR</i> and <i>virS</i> genes in <i>Galleria</i> model.

<p>Virulence of the wild type strain LS1223 (designated with white square), <i>virR</i> LS1224 (designated with black square) and <i>virS</i> LS1225 (designated with gray square) at the doses of (A) 10⁶CFU/larva (B) 10⁵CFU/larva, (C) 10⁴CFU/larva, a > b (P< 0.05).</p

Change of <i>Listeria</i> population following inoculation^*.

<p>Change of <i>Listeria</i> population following inoculation^{<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0184557#t002fn001" target="_blank">*</a>}.</p

LT₅₀ values for non-pathogenic and pathogenic <i>Listeria</i> spp. employed in this study^*.

<p>LT₅₀ values for non-pathogenic and pathogenic <i>Listeria</i> spp. employed in this study^{<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0184557#t001fn001" target="_blank">*</a>}.</p

Comparison of virulence of <i>L</i>. <i>monocytogenes</i> isogenic mutants in <i>G</i>. <i>mellonella</i>.

<p>Comparison between wild type <i>L</i>. <i>monocytogenes</i> strain LS1209 (designated with black square) and isogenic mutants with deletion in <i>prfA</i> LS496 (designated with white square) <i>hly</i> LS1212 (designated with light gray square), <i>plcA</i> LS1210 (designated with dark gray square), <i>plcB</i> LS1211 (designated with dark upward diagonal square) and <i>actA</i> LS1213 (designated with dark narrow horizontal square) in larvae infected at the doses of at the doses of (A) 10⁶ CFU/larva (B) 10⁵ CFU/larva, (C) 10⁴ CFU/larva > b >c (P<0.05). Presented results are average of three independent trials.</p

Comparison of the virulence potential of clinical and food isolates of <i>L</i>. <i>monocytogenes</i> strains related to listeriosis outbreaks with invasive and non-invasive (gastroenteritis) symptoms.

<p>Parallel testing of the clinical isolates of the same serotype related to non-invasive (LS405 –designated with black square and LS403- designated with dark gray square) and invasive (LS740-designated with white square and LS414-designated with light gray square) outbreaks at the inoculum concentrations of 10⁶CFU/larva (6A), 10⁵ CFU/larva (6B) and 10⁴ CFU/larva (6C); Paired food isolates related to non-invasive (LS404- designated with black square and LS402- designated with dark gray square) and invasive (LS670- designated with white square and LS413- designated with light gray square) outbreaks have also been compared at the inoculum concentrations of 10⁶CFU/larva (6A1), 10⁵CFU/larva (6B1) and 10⁴CFU/larva (6C1); a < b (P<0.05), c < d (P<0.05).</p

LT₅₀ of <i>G</i>. <i>mellonella</i> larvae at 37°C after inoculation with <i>L</i>. <i>monocytogenes</i> isogenic mutant ^#.

<p>LT₅₀ of <i>G</i>. <i>mellonella</i> larvae at 37°C after inoculation with <i>L</i>. <i>monocytogenes</i> isogenic mutant ^{<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0184557#t003fn001" target="_blank">#</a>}.</p

Survey of undeclared egg allergen levels in the most frequently recalled food types (including products bearing precautionary labelling)

<p>Since the number of recalls involving undeclared allergens is commonly associated with bakery and snack foods, we aimed to determine the frequency of egg allergens in a large number of these products using two commercial enzyme-linked immunosorbent assay (ELISA) methods. Samples were chosen that either had no egg identified on the product label or which had an egg precautionary statement. Among all samples, egg protein was detected in 5% of products using a Morinaga (MO) kit and 1% of products using a R-Biopharm (RB) kit. For bakery samples, egg protein was detected in 6% of 363 samples with no precautionary labelling (6% by MO and 1% by RB kit) and 12% of 80 samples which had precautionary labelling. For snack samples, egg protein was detected in 2% of 371 samples with no precautionary labelling (2% by MO and < 1% by RB kit) and 5% of 21 samples which had precautionary labelling. The disagreement rates between two methods were 5.2% for bakery products and 2.6% for snack products. The sample repeatability was at an acceptable level for bakery (< 12.5%) and snack foods (< 7.5%) for each method. The relative standard deviation between test kits was high (103.1%) for bakery foods. Four bakery products without precautionary labelling had a higher level of egg protein per serving compared with the eliciting dose (ED₁₀ of 3.7 mg protein) for egg allergic patients. These results highlight the fact that detection methodology plays a vital role for accurate labelling control and mitigation of risk for egg allergic consumers.</p