Microbial and biochemical characterisation of fermented house crickets (Acheta domesticus) and mealworm larvae (Tenebrio molitor)

Jamnik, Polona (author), Mahnič, Nik (author), Ekselenski, Simon (author), Pogačnik da Silva, Lea (author), Čadež, Neža (author), Membrino, Valentina (author), Poklar Ulrih, Nataša (author), Plateis, Zala (author), Toplak, Nataša (author), Koren, Simon (author), Kulma, Martin (author), Kouřimská, Lenka (author), Škvorová, Petra (author), Jeršek, Barbara (author)

Edible insects have a large potential to be an alternative source of proteins for human consumption. Lactic acid fermentation can further increase availability of proteins as well as increase functional value of substrates. Thus, the study aimed to microbiologically and biochemically characterise house crickets (Acheta domesticus) and mealworm larvae (Tenebrio molitor) before and after lactic acid fermentation. Both insects were shown as a suitable substrate for fermentation which lasted 48 hours. Results of microbiological characterisation using culture-dependent microbiological methods show that reared, lyophilized and milled insects have fairly high viable microbial counts determined as aerobic (>7.00 log CFU/g) and anaerobic (>6 log CFU/g) mesophilic bacteria, lactic acid bacteria (>6 log CFU/g) and enterococci (>5 log CFU/g) prior fermentations and all counts were even higher after fermentations, but no pathogens were detected in any sample. High-throughput 16S ribosomal RNA gene sequencing revealed that most of bacteria (>96% relative abundance) in insects’ prior fermentation are represented by Proteobacteria, Firmicutes, Bacteroides and Actinobacteria and at genus level Enterococcus, Lactonifactor, Clostridium and Klebsiella dominated in house crickets, while in mealworm larvae Enterococcus, Erwinia and Pantoea were the most abundant along with Salmonella which relative abundance was reduced by nearly 100× with fermentations. Regardless of the type of insect, fermentations using the Lb. plantarum starter culture or meat starter culture resulted in the dominance of Lactobacillus, Pediococcus and Enterococcus. In samples fermented with no addition of starter culture, the same bacterial genera still prevailed, suggesting that the native bacteria (Ped. pentosaceus, Lb. graminis, Lb. sakei in both insects, and Ent. faecalis in house crickets and Ent. avium in mealworm larvae) played an important role in all fermentations. In spite of this both fermented insects differed in lactic acid concentration, free amino groups level and antioxidative activity, which were higher for mealworm larvae.

• Language: English
• Keywords: antioxidative activity, fermentation, insect raring, microbial counts, microbiome
• Work type: Article
• Typology: 1.01 - Original Scientific Article
• Organization: BF - Biotechnical Faculty
• Publication status: Published
• Publication version: Version of Record
• Publication date: 01.01.2025
• Year: 2025
• Number of pages: Str. 3033-3053
• Numbering: Vol. 11, iss. 16
• PID: 20.500.12556/RUL-181662
• UDC: 579.67:595.71/.79
• ISSN on article: 2352-4588
• DOI: 10.1163/23524588-bja10246
• COBISS.SI-ID: 239454979
• Publication date in RUL: 10.04.2026

Record is a part of a journal

• Title: Journal of insects as food and feed
• Publisher: Wageningen Academic Publishers
• ISSN: 2352-4588
• COBISS.SI-ID: 526891289

Licences

• License: CC BY 4.0, Creative Commons Attribution 4.0 International
• Link: http://creativecommons.org/licenses/by/4.0/
• Description: This is the standard Creative Commons license that gives others maximum freedom to do what they want with the work as long as they credit the author.

Secondary language

• Language: Slovenian
• Keywords: užitne žuželke, insekti, fermentacija, antioksidativna aktivnost, mikrobiom fermentiranih žuželk

Projects

• Funder: ARIS - Slovenian Research and Innovation Agency
• Project number: P4-0116
• Name: Mikrobiologija in biotehnologija živil in okolja

• Funder: Czech Science Foundation
• Project number: GF21-47159L
• Name: INPROFF: Quality, Safety and Authenticity of INsect PROtein-Based Food and Feed Products