Lisa Siekmann

Dr. Lisa Siekmann


Research Focus & Metrics

Academic Career Length

9Years (2018-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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13 March 2021 in Current Clinical Microbiology Reports
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Journal Article
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LSLisa Siekmann
Lisa Siekmann
MPMadeleine Plötz
Madeleine Plötz
CKCarsten Krischek
Carsten Krischek
Purpose of Review: Curing—the treatment of meat products with nitrite and nitrate—is controversially discussed by consumers, as increased consumption of cured foods might negatively influence human health. Recent Findings: However, omitting of curing chemicals might reduce microbiological safety, thereby increasing the risk to consumer health. Also, besides the addition of nitrate/nitrite, meat products are additionally preserved within the hurdle principle by other methods such as chilling, ripening, or heating. Summary: The present article focuses on the addition of plants/plant extracts or plasma-treated water as nitrate sources and the direct treatment of meat products with plasma for nitrate generation. With regard to color and microbial safety of cured meat products, which are relevant to the consumers, promising results were also obtained with the alternative curing methods. Nonetheless, it is doubtful to what extent these methods are viable alternatives, as the curing chemicals themselves and not their origin are problematic for consumer health.

22 May 2023 in Insects
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BLBarbara Lemke
Barbara Lemke
LSLisa Siekmann
Lisa Siekmann
NGNils Th. Grabowski
Nils Th. Grabowski
MPMadeleine Plötz
Madeleine Plötz
CKCarsten Krischek
Carsten Krischek
The use of proteins from insects, plants, microalgae, fungi or bacteria as an alternative to proteins of animal origin such as meat, fish, eggs or milk can meet the worldwide protein demand in the future. As the consumption of whole insects might be problematic or unacceptable for many consumers, especially in European countries, the use of homogenized insects or protein extracts from insects for the production of products might be a possibility to overcome general acceptability problems. However, the quality criteria of these products have to be comparable with consumers’ expectations with regard to known products. Therefore, in the present study, we produced a meat product, replaced 10% and 20% of the pork with homogenized larvae of Tenebrio molitor and Hermetia illucens, and determined different physicochemical and sensory parameters at production and during modified atmosphere storage for 21 days. Additionally, the alteration of different bacteria species during this storage was analyzed in challenge tests. After production, the addition of insects resulted in higher cooking losses and pH values in the products with 20% insects, higher pH and yellowness, lower lightness, protein and hardness results in the Hermetia products, as well as higher yellowness and lower protein and hardness values in the cooked meat products with Tenebrio molitor. During modified atmosphere storage, the color differences principally remained, whereas the concentrations of inoculated Bacillus cereus, Listeria monocytogenes and Escherichia coli were not influenced by the addition of insects to the cooked meat products. The sensory results of the insect products, especially at higher concentrations and with Hermetia illucens, worsened during modified atmosphere storage. The addition of homogenized insect larvae, especially at higher concentrations and particularly of Hermetia illucens, influences different physicochemical and sensory parameters of the cooked meat products.

6 March 2023 in Foods
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VGVanessa Große-Peclum
Vanessa Große-Peclum
LSLisa Siekmann
Lisa Siekmann
CKCarsten Krischek
Carsten Krischek
GAGeorg Avramidis
Georg Avramidis
COChristian Ochs
Christian Ochs
MPMadeleine Plötz
Madeleine Plötz
Foodborne diseases are mainly caused by the contamination of meat or meat products with pathogenic microorganisms. In this study, we first investigated the in vitro application of TRIS-buffered plasma-activated water (Tb-PAW) on Campylobacter (C.) jejuni and Escherichia (E.) coli, with a reduction of approx. 4.20 ± 0.68 and 5.12 ± 0.46 log10 CFU/mL. Furthermore, chicken and duck thighs (inoculated with C. jejuni or E. coli) and breasts (with natural microflora) with skin were sprayed with Tb-PAW. Samples were packed under a modified atmosphere and stored at 4 °C for 0, 7, and 14 days. The Tb-PAW could reduce C. jejuni on days 7 and 14 (chicken) and E. coli on day 14 (duck) significantly. In chicken, there were no significant differences in sensory, pH-value, color, and antioxidant activity, but %OxyMb levels decreased, whereas %MetMb and %DeoMb increased. In duck, we observed slight differences in pH-value, color, and myoglobin redox forms for the Tb-PAW, which were not perceived by the sensory test persons. With only slight differences in product quality, its application as a spray treatment may be a useful method to reduce C. jejuni and E. coli on chicken and duck carcasses.

1 January 2018 in European Poultry Science
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Journal Article
Open access
LSLisa Siekmann
Lisa Siekmann
SJS. Janisch
S. Janisch
RWR. Wigger
R. Wigger
JUJ. Urban
J. Urban
JZJ. Zentek
J. Zentek
CKCarsten Krischek
Carsten Krischek
Introduction Today, more than 40 million day-old cockerels from specialized layer lines in Germany are culled due to their slower growth and less desirable meat characteristics (Koenig et al., 2012; Federal Statistical Office Germany, 2018). This

2 December 2022 in Applied Sciences
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VGVanessa Große-Peclum
Vanessa Große-Peclum
LSLisa Siekmann
Lisa Siekmann
CKCarsten Krischek
Carsten Krischek
GAGeorg Avramidis
Georg Avramidis
LBLars ten Bosch
Lars ten Bosch
MPMadeleine Plötz
Madeleine Plötz
Bovine digital dermatitis is an important infectious claw disease caused by multimicrobial infections with bacteria such as Fusobacterium (F.) necrophorum or Porphyromonas (P.) levii. To analyze the antibacterial effects of a TRIS-buffered plasma-activated water (Tb-PAW) on the bacterial number of F. necrophorum, P. levii, Escherichia (E.) coli, Staphylococcus (S.) aureus and Clostridium (C.) sporogenes 1 mL of each bacterial solution (106–108 CFU/mL) was incubated with 9 mL Tb-PAW up to 15 min. E. coli, F. necrophorum and P. levii were significantly reduced by 5.0 log after 1 min of treatment, while S. aureus and C. sporogenes required 15 min to reach a 3.0 log reduction. The addition of bovine serum albumin did not negatively affect the bactericidal effect. Tb-PAW storage at 7 °C and 21 °C is possible for up to 24 h without any change in the bactericidal effect, while Tb-PAW stored at 30 °C can only be used for a period of 12 h. The present data indicate that Tb-PAW can be used to reduce various bacteria even under the influence of different parameters. However, due to the complexity of Tb-PAW, further studies are required to ensure its microbicidal activity before practical application.

23 March 2024 in Pathogens
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JHJan Bernd Hinrichs
Jan Bernd Hinrichs
AKAntonia Kreitlow
Antonia Kreitlow
LSLisa Siekmann
Lisa Siekmann
MPMadeleine Plötz
Madeleine Plötz
Nicole KemperNicole Kemper
Nicole Kemper
AAAmir Abdulmawjood
Amir Abdulmawjood
In this study, changes in hepatitis E virus (HEV) contamination in the production of liver sausage from naturally contaminated pork liver were investigated. Furthermore, the potential effectiveness of individual production parameters in reducing viral loads was measured. When processing moderately contaminated liver (initial Cq-value 29), HEV RNA persisted in the finished sausages, even after heating for 90 min at 75 °C. A matrix-specific standard curve was created using a spiking experiment to accurately quantify HEV RNA in a particularly challenging matrix like liver sausage. Variations in product-specific production parameters, including mincing and heating times, showed some reduction in contamination levels, but even prolonged heating did not render all finished products HEV negative. The persistence of HEV contamination underscores the importance of ongoing monitoring in the pig population and raw materials to enhance food safety measures and reduce the likelihood of transmission through pork consumption. The detection of HEV RNA within all processing stages of pork liver in the production of liver sausage suggests that further research into the risk of infection posed by this detection and vigilance in managing HEV risks in the food chain, particularly in pork products, are required to protect public health.