Food Spoilage Microorganisms Research Articles

The complex multicellular morphology of the food spoilage bacteria Brochothrix thermosphacta strains isolated from ground chicken.

Herein we describe a highly structured, filamentous growth phenotype displayed by an isolate of the food spoilage microorganism Brochothrix thermosphacta. The growth morphology of this B. thermosphacta strain (strain BII) was dependent on environmental factors such as the growth media, incubation temperatures, and the inoculum concentration. Inoculation of cultures in highly dilute suspensions resulted in the formation of isolated, tight aggregates resembling fungal growth in liquid media. This same strain also formed stable, mesh-like structures in 6-well tissue culture plates under specific growth conditions. The complex growth phenotype does not appear to be unique to strain BII but was common among B. thermosphacta strains isolated from chicken. Light and electron micrographs showed that the filaments of multiple BII cells can organize into complex, tertiary structures resembling multistranded cables. Time-lapse microscopy was employed to monitor the development of such aggregates over 18 h and revealed growth originating from short filaments into compact ball-like clusters that appeared fuzzy due to protruding filaments or cables. This report is the first to document this complex filamentous growth phenotype in a wild-type bacterial isolate of B. thermosphacta.

Biogenic Amine Contents and Microbial Characteristics of Cambodian Fermented Foods.

Naturally fermented foods are an important part of the typical diet in Cambodia. However, the food safety status of these products has not been widely studied. The aim of this study was, therefore, to provide an overview of the quality of these foods in relation to microbiology and biogenic amines. Additionally, the obtained results were compared to the habits and practices of Cambodians in handling this type of food. A total of 57 fermented foods (42 fishery and 15 vegetable products) were collected from different retail markets in the capital of Cambodia. Pathogenic Salmonella spp., Listeria spp., and Listeria monocytogenes were not detected in 25 g samples. Generally, less than 102 cfu/g of Staphylococcus aureus, Escherichia coli, Pseudomonas spp., Enterobacteriaceae, and molds were present in the fermented foods. Bacillus cereus group members (<102 to 2.3 × 104 cfu/g), lactic acid bacteria (<102 to 1.1 × 107 cfu/g), halophilic and halotolerant bacteria (<102 to 8.9 × 106 cfu/g), sulfite-reducing Clostridium spp. (<102 to 3.5 × 106 cfu/g), and yeasts (<102 to 1.1 × 106 cfu/g) were detected in this study. Still, the presence of pathogenic and spoilage microorganisms in these fermented foods was within the acceptable ranges. Putrescine, cadaverine, tyramine, and histamine were detected in 100%, 89%, 81%, and 75% of the tested products, respectively. The concentrations of histamine (>500 ppm) and tyramine (>600 ppm) were higher than the recommended maximum levels in respectively four and one of 57 fermented foods, which represents a potential health risk. The results suggest that the production process, distribution, and domestic handling of fermented foods should be re-evaluated. Further research is needed for the establishment of applicable preservation techniques in Cambodia.

Evaluation of the Potential of Biofilm Formation of Bifidobacterium longum subsp. infantis and Lactobacillus reuteri as Competitive Biocontrol Agents Against Pathogenic and Food Spoilage Bacteria.

This study proposes to exploit the in vivo metabolism of two probiotics (Bifidobacterium longum subsp. infantis and Lactobacillus reuteri) which, upon adhesion on a solid surface, form a biofilm able to control the growth of pathogenic and food spoilage bacteria. The results showed that pathogenic cell loads were always lower in presence of biofilm (6.5–7 log CFU/cm2) compared to those observed in its absence. For Escherichia coli O157:H7, a significant decrease (>1–2 logarithmic cycles) was recorded; for Listeria monocytogenes, Staphylococcus aureus, and Salmonella enterica, cell load reductions ranged from 0.5 to 1.5 logarithmic cycles. When tested as active packaging, the biofilm was successfully formed on polypropylene, polyvinyl chloride, greaseproof paper, polyethylene and ceramic; the sessile cellular load ranged from 5.77 log CFU/cm2 (grease-proof paper) to 6.94 log CFU/cm2 (polyethylene, PE). To test the potential for controlling the growth of spoilage microorganisms in food, soft cheeses were produced, inoculated with L. monocytogenes and Pseudomonas fluorescens, wrapped in PE pellicles with pre-formed biofim, packed both in air and under vacuum, and stored at 4 and 15 °C: an effective effect of biofilms in slowing the decay of the microbiological quality was recorded.

ОТБОР АНТАГОНИСТИЧЕСКИ АКТИВНЫХ ШТАММОВ МОЛОЧНОКИСЛЫХ БАКТЕРИЙ ИЗ МОЛОКА РАЗЛИЧНЫХ ВИДОВ ЖИВОТНЫХ

Dairy products make up the bulk of functional fermented foods with a wide range of health benefits. One of the beneficial effects of fermented products is the ability of bacteria used as starter cultures to suppress pathogens and food spoilage microorganisms. Milk of various animal species is noted in the scientific literature as a valuable source for the isolation of new types of microorganisms. We selected 28 isolates of biotechnologically valuable lactic acid bacteria from raw mare, camel and goat milk. The antagonistic activity of isolates from raw milk of various animal species and fermented mare's milk (koumiss) in relation to a number of bacterial test cultures was studied. A wide spectrum of antibacterial activity of isolates from koumiss against Escherichia coli, Sarcina flava, S. flava T, Salmonella dublin, Mycobacterium citreum, M. rubrum, I Tsenkovsky vaccine was shown. Molecular genetic identification of 12 selected microorganisms was carried out. Antagonistically active lactic acid bacteria of koumiss are defined as L. paracasei, L. fermentum, L. rhamnosus and L. diolivorans. Selected microorganisms will be used to create starter cultures for table and preventive beveragess and products with directed action. Key words: koumiss, lactic acid bacteria, antagonism, antibacterial activity, molecular genetic identification.

Effect of cold atmospheric pressure plasma-activated water on the microbial safety of Korean rice cake

We evaluated the effect of plasma-activated water (PAW) on the populations of foodborne pathogens and food-spoilage microorganisms on Korean rice cake. PAW was produced by treating distilled water with two atmospheric dielectric-barrier discharges (51.7 W, 14.4 kHz, air discharge) for 20 min. The inactivation effect of PAW on indigenous microorganism and inoculated Escherichia coli O157:H7, Salmonella Typhimurium, Listeria monocytogenes, Penicillium chrysogenum and Candida albicans on Korean rice cake were measured and their effect on the color and texture values of the samples were determined. PAW treatment for 20 min reduced the numbers of the three foodborne pathogens by about 2.0 log CFU/g. PAW treatment for 20 min reduced the numbers of total aerobes, P. chrysogenum, and C. albicans by 2.78, 1.97, and 1.00 log CFU/g, respectively. The antimicrobial effect of PAW was not significantly different from 0.2 ppm of sodium hypochlorite solution, which is used in Korean rice cake production. PAW treatment did not affect the color, texture, or pH of Korean rice cake. Therefore, PAW treatment can be used as an alternative method to reduce safety risk and spoilage of Korean rice cake without deteriorating its quality.

Nutritional Characteristics and Antimicrobial Activity of Australian Grown Feijoa (Acca sellowiana).

The present study determined the chemical composition, bioactive compounds and biological properties of Australian grown feijoa (Acca sellowiana), including whole fruit with peel, fruit peel and pulp, in order to assess the nutritional quality and antimicrobial activity of this emerging subtropical fruit. Polyphenolic compounds and vitamins were determined by UHPLC-PDA-MS/MS, showing that the feijoa fruit not only contains high amounts of antioxidant flavonoids, but is also a valuable source of vitamin C (63 mg/100 g FW (fresh weight)) and pantothenic acid (0.2 mg/100 g FW). Feijoa fruit is also a good source of dietary fibre (6.8 g/100 g FW) and potassium (255 mg/100 g FW). The edible fruit peel possesses significantly (p < 0.05) higher amounts of antioxidant flavonoids and vitamin C than the fruit pulp. This is most likely the reason for the observed strong antimicrobial activity of the peel-extracts against a wide-range of food-spoilage microorganism. The consumption of feijoa fruit can deliver a considerable amount of bioactive compounds such as vitamin C, flavonoids and fibre, and therefore, may contribute to a healthy diet. Furthermore, the potential use of feijoa-peel as a natural food perseverative needs to be investigated in follow-up studies.

Growth Biocontrol of Foodborne Pathogens and Spoilage Microorganisms of Food by Polish Propolis Extracts.

Propolis is a natural mixture produced by bees from plant resin substances. This study focuses on the general characteristics of five samples of Polish extract propolis originating from agricultural areas. Chemical composition with high performance liquid chromatography‒diode array detector method, total content of flavonoids and polyphenols, and antioxidative activity were determined in the ethanol extracts of propolis (EEP) samples. Minimum inhibitory concentration (MIC), minimum bactericidal/fungicidal concentration (MBC/MFC) and time-kill curves were studied for foodborne pathogens and food spoilage microorganisms. In EEPs the predominant flavonoid compounds were pinocembrin, chrysin, pinobanksin, apigenin, and kaempferol and the predominant phenolic acids were p-coumaric acid, ferulic acid, and caffeic acid. A strong antioxidative action of propolis in vitro was observed (IC50 for DPPH radical was at the level of 0.9–2.1 µg/mL). EEPs had MIC values for bacteria in the range of 1–16 mg/mL, whereas MIC for fungi ranged from 2 to 32 mg/mL. Extract of propolis originating from southern Poland was distinguished by higher content of bioactive components, and stronger antioxidative and antimicrobial activity than EPPs from the remaining areas of Poland. The results indicate the possibility of applying ethanol extracts from Polish propolis to protect food against microbiological spoilage.

Ocins for Food Safety.

The food industry produces highly perishable products. Food spoilage represents a severe problem for food manufacturers. Therefore, it is important to identify effective preservation solutions to prevent food spoilage. Ocins (e.g., bacteriocins, lactocins, and enterocins) are antibacterial proteins synthesized by bacteria that destroy or suppress the growth of related or unrelated bacterial strains. Ocins represent a promising strategy for food preservation, because of their antagonist effects toward food spoilage microorganisms, high potency, and low toxicity. Additionally, they can be bioengineered. The most common and commercially available ocins are nisin, plantaracin, sakacin P, and pediocin. Several ocins have been characterized and studied biochemically and genetically; however, their structure-function relationship, biosynthesis, and mechanism of action are not understood. This narrative review focuses primarily on ocins and their relevance to the food industry to help prevent food spoilage. In particular, the applications and limitations of ocins in the food industry are highlighted.

Heterologous expression and functional analysis of the F-box protein Ucc1 from other yeast species in Saccharomyces cerevisiae

The ubiquitin-proteasome system plays an important role in metabolic regulation. In a previous study, we reported that, in Saccharomyces cerevisiae, when glucose is available, the SCFUcc1 ubiquitin ligase complex targets citrate synthase 2 (Cit2) for proteasomal degradation, thereby suppressing the glyoxylate cycle, an anabolic pathway that replenishes the TCA cycle with succinate for the activation of gluconeogenesis. However, the roles of Ucc1 in other yeast species remain unclear. Here, we cloned orthologs of the F-box protein Ucc1 from Zygosaccharomyces bailii, an aggressive food spoilage microorganism that is the most acetic acid-tolerant yeast species, and Candida glabrata, an emerging fungal pathogen. These orthologs were expressed in S.cerevisiae, and their activities were tested genetically and biochemically. The results showed that Z.bailii Ucc1 rescued the ucc1Δ phenotype, suggesting the existence of a similar mechanism regulating the glyoxylate cycle in Z.bailii. By contrast, C.glabrata Ucc1 did not complement the ucc1Δ phenotype or exhibit a dominant negative effect on Ucc1. These results suggest the importance of analysing the regulatory mechanisms of glyoxylate cycle in a broad range of yeast species.

Bioactivity Potentials of Biodegradable Chitosan/Gelatin Film Forming Solutions Combined with Monoterpenoid Compounds

Novel food packaging systems including biodegradable/edible films have been introduced to the market for consumers who desire natural products for their nutrition. Biochemically active plant compounds are added to the biopolymer-based films to improve their functionality. Within the present study, chitosan (1%) and gelatin (4%) biopolymer-based film forming solutions (FFSs) combined with 1, 2, 5 and 10% (v/v) eugenol, pulegone and carvacrol, monoterpenoid compounds, were evaluated for their antimicrobial and antioxidative potential. Antioxidant activities and total phenolic contents (TPC) of the FFSs were determined by 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging activity and Folin–Ciocalteau assays, respectively. Screening the antimicrobial activity of FFSs were performed against food spoilage microorganisms including Bacillus cereus, Escherichia coli, Salmonella typhimurium, Staphylococcus aureus and Listeria monocytogenes and a fungi, Candida albicans by using agar well diffusion method. The chitosan FFS containing 10% carvacrol had greater TPC (3857.3 ± 0.07 mg gallic acid equivalent/L). The highest antioxidative capacity was observed for the chitosan FFS containing 10% eugenol as 97.92 ± 0.01%. FFSs with monoterpenoids showed promising antimicrobial activities against tested microorganisms. Based on antioxidative and antimicrobial potentials of the FFSs, it can be envisaged to use monoterpenoid incorporation to biopolymer films for food packaging applications.

The Preservative Efficacy of Antimicrobial Proteins and Metabolites from Microorganisms, Animals and Plants as Potential Alternative to Chemical Food Preservation: A Review

Food is a source of nutrients and energy for humans and animals. Though food is assumed to be safe for consumption, it is highly susceptible for microbial contamination responsible for health risks and economic loss. This requires the mechanism that keep food fresh and safe for extended period of time. So far, in human history various physical and chemical methods have been employed to extend shelf life. Unfortunately, these methods are found to have a lot of drawbacks that pose problem on the quality and safety of the product beyond consumer need. Biological preservation using microbial, plant and animal derived metabolites and antimicrobial peptides has recently got considerable attention as the safest way of extending shelf life of food with no adverse effects on product quality. The antimicrobial efficiency of antimicrobial peptides and metabolites have been found to significantly inhibit the growth of potent food borne pathogens and spoilage microorganisms. However, the efficacy of biological antimicrobial agents for food preservation is potentiated by combined application with fewer chemical preservatives with smart formulation of a series of hurdle called hurdle technology. In this review, reports on the efficacy of antimicrobial peptides and metabolites of microbes, plants and animals in preserving various food stuffs are well reviewed during independent application and as part of hurdle system. Keywords: Biological preservation, Food, Food quality, Hurdle technology, Microbial/plant/animal metabolites DOI : 10.7176/FSQM/87-05 Publication date :May 31 st 2019

Antioxidant and antimicrobial effect of turmeric oil, boswellia oil and neem oil on pathogenic and food spoilage microorganisms

Antioxidant and antimicrobial effect of turmeric oil, boswellia oil and neem oil on pathogenic and food spoilage microorganisms

A Control Alternative for the Hidden Enemy in the Wine Cellar

Brettanomyces bruxellensis has been described as the principal spoilage yeast in the winemaking industry. To avoid its growth, wine is supplemented with SO2, which has been questioned due to its potential harm to health. For this reason, studies are being focused on searching for, ideally, natural new antifungals. On the other hand, it is known that in wine production there are a variety of microorganisms, such as yeasts and bacteria, that are possible biological controls. Thus, it has been described that some microorganisms produce antimicrobial peptides, which might control yeast and bacteria populations. Our laboratory has described the Candida intermedia LAMAP1790 strain as a natural producer of antimicrobial compounds against food spoilage microorganisms, as is B. bruxellensis, without affecting the growth of S. cerevisiae. We have demonstrated the proteinaceous nature of the antimicrobial compound and its low molecular mass (under 10 kDa). This is the first step to the possible use of C. intermedia as a selective bio-controller of the contaminant yeast in the winemaking industry.

Selection of nerolidol among a series of terpenic and phenolic compounds for its potent activity against Lactobacillus fermentum ATCC 9338

Abstract Essential oil components are widely used for their antibacterial activity against spoilage microorganisms in food. Lactobacillus fermentum is a Gram-positive lactic acid bacteria responsible for the deterioration of various food products, including beverages and dairy products. In this study, 17 terpenic and 11 phenolic compounds were screened against the food spoilage microorganism Lactobacillus fermentum ATCC 9338. The antibacterial activity of the tested compounds was dependent on hydrophobicity and particular chemical features. Nerolidol solubilized in dimethylsulfoxide exhibited the highest antibacterial activity and showed low minimal inhibitory (MIC: 25 μM) and minimal bactericidal (MBC: 50 μM) concentrations. Moreover, no viable cells were detected within 16 h of incubation at 50 μM. The important antibacterial activity of nerolidol against L. fermentum is probably related to the high hydrophobicity, the aliphatic chain length, and the presence of the hydroxyl group. Hydroxypropyl-β-cyclodextrin/nerolidol inclusion complex showed MIC and MBC values of 100 and 200 μM, respectively. The total bacterial kill was observed after 12 h of incubation. The results obtained with the inclusion complex are probably due to the time required to allow nerolidol to be released from the inclusion complex.

Effect of pulsed electric field treatment on shelf life and nutritional value of apple juice

The aim of this study was to assess shelf life and nutritional value of apple juice, including the content of bioactive compounds, after pulsed electric field (PEF) treatment, taking into account different number of cycles: 4, 6, 8 (total 200, 300, and 400 pulses, respectively). Determination of vitamin C and polyphenols concentration, antioxidant activity as well as microbiological analysis were conducted immediately after PEF process and after 24, 48 and 72 h of storage. The results showed that PEF did not affect the content of bioactive compounds. PEF-treated juice did not show changes in the amount of vitamin C and total polyphenols during the storage for 72 h under refrigeration. PEF treatment was effective method for inactivation of a wide range of most common food spoilage microorganisms. PEF process can be used as an effective method of food preservation, allowing prolongation of shelf life and protection of nutritional value. This brings new opportunities for obtaining safe, healthy and nutritious food.

Discovery of novel quaternary ammonium compounds based on quinuclidine-3-ol as new potential antimicrobial candidates

Quaternary ammonium compounds (QACs) are amphiphilic molecules displaying a broad-spectrum of antibacterial activity. QACs are commonly used antiseptics in industrial, home and hospital settings. Given the emergence of the QAC-resistant bacteria, there is an urgent need to design new QACs with good antimicrobial activity, able to escape the host resistance mechanism. Therefore, a series of QACs derived from quinuclidine-3-ol and an alkyl chain of variable length (QOH-C3 to -C14), was designed and synthesized. The antimicrobial potential of the new monoquaternary QACs was surveyed against seventeen strains of emerging food spoilage and pathogenic microorganisms, including clinical multidrug-resistant ESKAPE isolates. The QOH-C14 proved to have the strongest antimicrobial activity. It was highly active against all pathogens tested, particularly against the Gram-positive bacteria with minimal inhibitory concentrations (MICs) ranging from 0.06 to 3.9 μg/mL, and fungi exerting the MIC90 between 0.12 and 3.9 μg/mL. The potency of QOH-C14, confirmed that alkyl chains are an important part of the structure with their lengths playing a critical role in bioactivity of these compounds. The atomic force microscopy images show the disruption of a cell membrane upon the treatment with QOH-C14. These results were additionally confirmed by flow cytometry and fluorescence microscopy. A relatively low toxicity toward healthy human cells underline that QOH-C14 has a potential as new QAC antimicrobial candidate.

Development and validation of a TaqMan RT-PCR method for identification of mayonnaise spoilage yeast Pichia kudriavzevii

Food spoilage and its contamination with yeast and mold is a serious problem of food industry. Despite the high fat content, mayonnaise is an attractive substrate for food spoilage microorganisms. The aim of this study was to develop a method for yeast identification in mayonnaise and to test commercially available mayonnaises for the presence of these contaminating microorganisms. Based on the sequencing of intergenic regions ITS1 and ITS2, we identified a yeast microorganism that causes mayonnaise spoilage. We found that DNA sequences were more than 99% identical to the GenBank DNA sequences from Pichia kudriavzevii. We developed a specific to P. kudriavzevii TaqMan probe and primers. The reaction conditions were optimized regarding to the components concentration and temperature cycle. The minimum amount of P. kudriavzevii DNA that could be detected by developed method was 50 fg. The minimal number of P. kudriavzevii cells that could be detected by developed method without pre-enrichment was 50. We tested verified method with DNAs from microorganisms of different taxonomic groups that were obtained from three collections of microorganisms. Finally, we analyzed 20 different brands of mayonnaise from 14 producers and 10 different brands of mayonnaise sauce from seven producers. We determined the Cq parameter that characterizes transition of the fluorescence curve to the logarithmic phase and, therefore, correlates with the extent of sample contamination with P. kudriavzevii yeast. P. kudriavzevii was detected in six analyzed samples of mayonnaise and one sample of mayonnaise sauce.

Antimicrobial Properties and Mechanism of Action of Some Plant Extracts Against Food Pathogens and Spoilage Microorganisms.

This work aims to evaluate the antimicrobial potential of ethanolic and water extracts of roselle (Hibiscus sabdariffa), rosemary (Rosmarinus officinalis), clove (Syzygium aromaticum), and thyme (Thymus vulgaris) on some food pathogens and spoilage microorganisms. Agar well diffusion method has been used to determine the antimicrobial activities and minimum inhibitory concentrations (MIC) of different plant extracts against Gram-positive bacteria (Bacillus cereus, Staphylococcus aureus), Gram-negative bacteria (Escherichia coli, Salmonella enteritidis, Vibrio parahaemolyticus, and Pseudomonas aeruginosa), and one fungus (Candida albicans). The extracts exhibited both antibacterial and antifungal activities against tested microorganisms. Ethanolic roselle extract showed significant antibacterial activity (P < 0.05) against all tested bacterial strains, while no inhibitory effect on Candida albicans (CA) was observed. Only the ethanolic extracts of clove and thyme showed antifungal effects against CA with inhibition zones ranging from 25.2 ± 1.4 to 15.8 ± 1.2 mm, respectively. Bacillus cereus (BC) appears to be the most sensitive strain to the aqueous extract of clove with a MIC of 0.315%. To enhance our understanding of antimicrobial activity mechanism of plant extracts, the changes in internal pH (pHint), and membrane potential were measured in Staphylococcus aureus (SA) and Escherichia coli (EC) cells after exposure to the plant extracts. The results indicated that the plant extracts significantly affected the cell membrane of Gram-positive and Gram-negative bacteria, as demonstrated by the decline in pHint as well as cell membrane hyperpolarization. In conclusion, plant extracts are of great value as natural antimicrobials and can use safely as food preservatives.

Copper and copper nanoparticles: role in management of insect-pests and pathogenic microbes

Abstract Crop losses mainly occur due to biotic factors, which include soil-borne phytopathogens, insect pests, parasites, and predators. The major loss of food in the food industry is due to its spoilage by various microorganisms. With advancement in nanotechnology, the use of nanoparticles in food and agriculture crop yield can be improved. In this context, copper nanoparticles (CuNPs) have attracted a great deal of attention from all over the world due to their broad-spectrum antimicrobial activity. Copper is one of the key micronutrients, which plays an important role in growth and development of plants. CuNP-based fertilizer and herbicide can be used in agriculture. The small size of CuNPs facilitates their easy absorption by the plants. CuNPs can be promisingly used in the food packaging to avoid the growth of food spoilage microorganisms. The use of CuNP-based agar packaging materials has substantial potential to increase the shelf-life of food. The present review focuses on the application of Cu and CuNPs in food and agriculture. Moreover, antimicrobial and pesticidal properties of CuNPs are also discussed.

Pathogen killing pathogen: antimicrobial substance from Acinetobacter active against foodborne pathogens.

Antimicrobial substances (AMS) produced by bacteria may reduce or prevent the growth of pathogenic and spoilage microorganisms in food. In this study, 16 isolates of Acinetobacter baumannii/calcoaceticus (ABC) complex, previously obtained from reconstituted infant milk formula (IMF) samples and the preparation and distribution utensils from the nursery of a public hospital, were used to screen for AMS production. Antimicrobial substance production and spectrum of activity assays were performed by agar-spot assay. Optimization of growth conditions for AMS production was also evaluated. Three (17.6%) isolates, namely JE3, JE4, and JE6, produced AMS against the principal indicator strain Salmonella enterica subsp. enterica serotype Typhi ATCC 19214. JE6 was also able to inhibit strains of Klebsiella pneumoniae, Proteus vulgaris, and Bacillus cereus, a Gram-positive bacteria. Remarkably, JE6 was able to inhibit all the tested resistant and multidrug-resistant (MDR) strains of the ABC complex and Shigella dysenteriae associated with IMF and utensils, indicating a potentially valuable application. AMS produced by JE6 does not appear to be affected by proteolytic enzymes and the producer strain showed specific immunity to its own AMS. This study highlights AMS produced by Acinetobacter with applications against MDR spoilage and foodborne pathogens - some of them, infectious disease causing agents - which, to our knowledge, has not been previously described.