Microbial Biofilms at Meat-Processing Plant as Possible Places of Bacteria Survival

Abstract

Biofilm contamination in food production threatens food quality and safety, and causes bacterial infections. Study of food biofilms (BF) is of great importance. The taxonomic composition and structural organization of five foods BF taken in different workshops of a meat-processing plant (Moscow, RF) were studied. Samples were taken from the surface of technological equipment and premises. Metagenomic analysis showed both similarities in the presented microorganisms dominating in different samples, and unique families prevailing on certain objects were noted. The bacteria found belonged to 11 phyla (no archaea). The dominant ones were Actinobacteria, Bacteroidetes, Firmicutes, and Proteobacteria. The greatest diversity was in BFs taken from the cutting table of raw material. Biofilms’ bacteria may be the cause of meat, fish and dairy products spoilage possible representatives include Pseudomonas, Flavobacterium, Arcobacter, Vagococcus, Chryseobacterium, Carnobacterium, etc.). Opportunistic human and animal pathogens (possible representatives include Arcobacter, Corynebacterium, Kocuria, etc.) were also found. Electron-microscopic studies of BF thin sections revealed the following: (1) the diversity of cell morphotypes specific to multispecies BFs; (2) morphological similarity of cells in BFs from different samples, micro-colonial growth; (3) age heterogeneity of cells within the same microcolony (vegetative and autolyzed cells, resting forms); (4) heterogeneity of the polymer matrix chemical nature according to ruthenium red staining.

Forms of Bacterial Survival in Model Biofilms

“…The present study emphasizes the role of age-related heterogeneity of biofilms, namely the coexistence of not only dividing vegetative cells, but also stationary and dormant ones, as one of the causes of stress resistance in BFs. Earlier, coexistence of vegetative (dividing and stationary) cells and dormant forms (DF) with the specific ultrastructural organization was shown in BFs isolated in meat processing plants [42].…”

“…The determining characteristics of DFs, besides their high stress resistance, in particular, thermal resistance, are distinctive features of the ultrastructural organization: thickened cell wall and bio-crystallized nucleotide developing as a result of the interaction of the stationary phase protein (Dps) with DNA, which leads to the development of the condensed nucleotide in the central part of DFs. When studying biofilms isolated in meat processing plants, we systematically found DFs in them, which were well-diagnosed using electron microscopy of thin sections of DFs [42]. In the present work, we studied the organization of the 6-day mono-species BFs (Figure 7) and cell ultrastructure of 2-and 28-day BFs of the model bacteria (Figure 8).…”

Ways of Long-Term Survival of Hydrocarbon-Oxidizing Bacteria in a New Biocomposite Material—Silanol-Humate Gel

“…Interestingly, some cells possessed membrane projections, which were converted into membrane vesicles ( Figure 6 d,e). Such structures are typical of the biofilm state of bacteria [ 21 , 22 , 23 , 24 , 25 ]. Some stationary cells possessed a pronounced capsule ( Figure 6 f), which is also characteristic of the biofilm phenotype.…”

Microbial Biofilms in a Meat Processing Environment

“…This resistance is mediated by the physical barrier provided by EPS, efflux systems, differentiation of bacterial cells to an inactive state or modification of the microenvironment that may make a particular sanitizer less effective (Giaouris et al, 2014;Yang et al, 2023). In addition, bacteria growing in biofilms have an increased exchange of genetic information, which can result in the rapid spread of genes encoding, e.g., antibiotic resistance, between bacterial populations (Hausner and Wuertz, 1999;Ch´ng et al, 2019;Nikolaev et al, 2022a).…”