Impact of the ABO and RhD Blood Groups on the Evaluation of the Erythroprotective Potential of Fucoxanthin, β-Carotene, Gallic Acid, Quercetin and Ascorbic Acid as Therapeutic Agents against Oxidative Stress

Previous studies detail that different blood groups are associated with incidence of oxidative stress-related diseases such as certain carcinomas. Bioactive compounds represent an alternative for preventing this oxidative stress. The aim of this study was to elucidate the impact of blood groups on the erythroprotective potential of fucoxanthin, β-Carotene, gallic acid, quercetin and ascorbic acid as therapeutic agents against oxidative stress. The impact of ABO blood groups on the erythroprotective potential was evaluated via the antioxidant capacity, blood biocompatibility, blood susceptibility and erythroprotective potential (membrane stabilization, in vitro photostability and antihemolytic activity). All tested antioxidants exhibited a high antioxidant capacity and presented the ability to inhibit ROO•-induced oxidative stress without compromising the cell membrane, providing erythroprotective effects dependent on the blood group, effects that increased in the presence of antigen A. These results are very important, since it has been documented that antigen A is associated with breast and skin cancer. These results revealed a probable relationship between different erythrocyte antigens with erythroprotective potential, highlighting the importance of bio-targeted drugs for groups most susceptible to certain chronic-degenerative pathologies. These compounds could be applied as additive, nutraceutical or encapsulated to improve their bioaccessibility.

Genomic Insights into Listeria monocytogenes: Organic Acid Interventions for Biofilm Prevention and Control

Listeria monocytogenes is an important pathogen that has been implicated in foodborne illness. The aim of the present study was to investigate the diversity of virulence factors associated with the mechanisms of pathogenicity, persistence, and formation of biofilm L. monocytogenes by tandem analysis of whole-genome sequencing. The lineages that presented L. monocytogenes (LmAV-2, LmAV-3, and LmAV-6) from Hass avocados were lineages I and II. Listeria pathogenicity island 1 (LIPI-1) and LIPI-2 were found in the isolates, while LIPI-3 and Listeria genomic island (LGI-2) only was in IIb. Stress survival island (SSI-1) was identified in lineage I and II. In the in silico analysis, resistance genes belonging to several groups of antibiotics were detected, but the bcrABC and transposon Tn6188 related to resistance to quaternary ammonium salts (QACs) were not detected in L. monocytogenes. Subsequently, the anti-L. monocytogenes planktonic cell effect showed for QACs (MIC = 6.25 ppm/MBC = 100 ppm), lactic acid (MBC = 1 mg/mL), citric acid (MBC = 0.5 mg/mL) and gallic acid (MBC = 2 mg/mL). The anti-biofilm effect with organic acids (22 °C) caused a reduction of 4-5 log10 cfu/cm2 after 10 min against control biofilm L. monocytogenes formed on PP than SS. This study is an important contribution to understanding the genomic diversity and epidemiology of L. monocytogenes to establish a control measure to reduce the impact on the environment and the consumer.

Genetic and compositional analysis of biofilm formed by Staphylococcus aureus isolated from food contact surfaces

INTRODUCTION

Staphylococcus aureus is an important pathogen that can form biofilms on food contact surfaces (FCS) in the dairy industry, posing a serious food safety, and quality concern. Biofilm is a complex system, influenced by nutritional-related factors that regulate the synthesis of the components of the biofilm matrix. This study determines the prevalence of biofilm-associated genes and evaluates the development under different growth conditions and compositions of biofilms produced by S. aureus.

METHODS

Biofilms were developed in TSB, TSBG, TSBNaCl, and TSBGNaCl on stainless-steel (SS), with enumeration at 24 and 192 h visualized by epifluorescence and scanning electron microscopy (SEM). The composition of biofilms was determined using enzymatic and chemical treatments and confocal laser scanning microscopy (CLSM).

RESULTS AND DISCUSSION

A total of 84 S. aureus (SA1-SA84) strains were collected from 293 dairy industry FCS (FCS-stainless steel [n = 183] and FCS-polypropylene [n = 110]) for this study. The isolates harbored the genes sigB (66%), sar (53%), agrD (52%), clfB/clfA (38%), fnbA/fnbB (20%), and bap (9.5%). 99. In particular, the biofilm formed by bap-positive S. aureus onto SS showed a high cell density in all culture media at 192 h in comparison with the biofilms formed at 24 h (p < 0.05). Epifluorescence microscopy and SEM revealed the metabolically active cells and the different stages of biofilm formation. CLSM analysis detected extracellular polymeric of S. aureus biofilms on SS, such as eDNA, proteins, and polysaccharides. Finally, the level of detachment on being treated with DNase I (44.7%) and NaIO 4(42.4%) was greater in the biofilms developed in TSB compared to culture medium supplemented with NaCl at 24 h; however, there was no significant difference when the culture medium was supplemented with glucose. In addition, after treatment with proteinase K, there was a lower level of biomass detachment (17.7%) of the biofilm developed in TSBNaCl (p < 0.05 at 24 h) compared to that in TSB, TSBG, and TSBGNaCl (33.6, 36.9, and 37.8%, respectively). These results represent a deep insight into the composition of S. aureus biofilms present in the dairy industry, which promotes the development of more efficient composition-specific disinfection strategies.

Combination of Sorbitol and Glycerol, as Plasticizers, and Oxidized Starch Improves the Physicochemical Characteristics of Films for Food Preservation

The aim of this work was to use glycerol (Gly) and sorbitol (Sor) as plasticizers with oxidized starch potato (OS) to produce biodegradable and environmentally friendly films, and to demonstrate the resulting physicochemical and functional viability without subtracting the organoleptic characteristics of the food. Analyses by water vapor permeability (WVP), attenuated total reflection Fourier transform infrared spectra (ATR-FTIR), scanning electron microscopy (SEM), tensile strength (TS), and transparency (UV) showed that the best film result was with 1.5 g of Gly and 2.0 g of Sor, conferred shine, elasticity 19.42 ± 6.20%, and mechanical support. The starch oxidized to 2.5%, contributing a greater transparency of 0.33 ± 0.12 and solubility of 78.90 ± 0.94%, as well as less permeability to water vapor 6.22 ± 0.38 gmm^-2 d^-1 kPa^-1. The films obtained provide an alternative for use in food due to their organic compounds, excellent visual presentation, and barrier characteristics that maintain their integrity and, therefore, their functionality.

Efficacy of Novel Bacteriophages against Escherichia coli Biofilms on Stainless Steel

Biofilm formation by E. coli is a serious threat to meat processing plants. Chemical disinfectants often fail to eliminate biofilms; thus, bacteriophages are a promising alternative to solve this problem, since they are widely distributed, environmentally friendly, and nontoxic to humans. In this study, the biofilm formation of 10 E. coli strains isolated from the meat industry and E. coli ATCC BAA-1430 and ATCC 11303 were evaluated. Three strains, isolated from the meat contact surfaces, showed adhesion ability and produced extracellular polymeric substances. Biofilms of these three strains were developed onto stainless steel (SS) surfaces and enumerated at 2, 12, 24, 48, and 120 h, and were visualized by scanning electron microscopy. Subsequently, three bacteriophages showing podovirus morphology were isolated from ground beef and poultry liver samples, which showed lytic activity against the abovementioned biofilm-forming strains. SS surfaces with biofilms of 2, 14, and 48 h maturity were treated with mixed and individual bacteriophages at 8 and 9 log10 PFU/mL for 1 h. The results showed reductions greater than 6 log10 CFU/cm2 as a result of exposing SS surfaces with biofilms of 24 h maturity to 9 log10 PFU/mL of bacteriophages; however, the E. coli and bacteriophage strains, phage concentration, and biofilm development stage had significant effects on biofilm reduction (p < 0.05). In conclusion, the isolated bacteriophages showed effectiveness at reducing biofilms of isolated E. coli; however, it is necessary to increase the libraries of phages with lytic activity against the strains isolated from production environments.

Nosocomial pathogen biofilms on biomaterials: Different growth medium conditions and components of biofilms produced in vitro

BACKGROUND/PURPOSE (S)

Nosocomial pathogens can develop biofilms on hospital surfaces and medical devices; however, few studies have focused on the evaluation of mono-and dual-species biofilms developed by nosocomial pathogens under different growth conditions.

METHODS

This study investigated biofilm development by nosocomial pathogens (Acinetobacter baumannii, Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa) on biomaterials in different culture media and their components of the extracellular matrix biofilm.

RESULTS

The mono-species biofilms showed cell densities from 7.50 to 9.27 Log₁₀ CFU/cm² on natural rubber latex type I (NLTI) and from 7.58 to 8.79 Log₁₀ CFU/cm² on stainless steel (SS). Dual-species biofilms consisted of S. aureus + P. aeruginosa (7.87-8.27 Log₁₀ CFU/cm² in TSBP and TSBME onto SS; p < 0.05), E. coli + P. aeruginosa (8.32-8.86 Log₁₀ CFU/cm² in TSBME onto SS and TSBP onto NLTI; p < 0.05), and S. aureus + E. coli (7.82 Log₁₀ CFU/cm² in TSBME onto SS; p < 0.05). Furthermore, biofilm detachment after proteinase K treatment was 5.54-32.81% compared to 7.95-24.15% after DNase I treatment in the mono-dual species biofilm matrix. Epifluorescence microscopy and scanning electron microscopy (SEM) enabled visualizing the bacteria and extracellular polymeric substances of biofilms on SS and NLTI.

CONCLUSION

Nosocomial pathogens can develop biofilms on biomaterials. Mono-species biofilms of Gram-negative bacteria showed lower densities than dual-species biofilms in TSBME and TSBP. Additionally, dual-species biofilms showed a higher concentration of proteins and eDNA in the extracellular matrix.

Kinetics of biofilm formation by pathogenic and spoilage microorganisms under conditions that mimic the poultry, meat, and egg processing industries

Pathogens and spoilage microorganisms can develop multispecies biofilms on food contact surfaces; however, few studies have been focused on evaluated mixed biofilms of these microorganisms. Therefore this study investigated the biofilm development by pathogenic (Bacillus cereus, Escherichia coli, Listeria monocytogenes, and Salmonella enterica Enteritidis and Typhimurium serotypes) and spoilage (Bacillus cereus and Pseudomonas aeruginosa) microorganisms onto stainless-steel (SS) and polypropylene B (PP) coupons; under conditions that mimic the dairy, meat, and egg processing industry. Biofilms were developed in TSB with 10% chicken egg yolk (TSB + EY), TSB with 10% meat extract (TSB + ME) and whole milk (WM) onto SS and PP. Each tube was inoculated with 25 μL of each bacteria and then incubated at 9 or 25 °C, with enumeration at 1, 48, 120, 180 and 240 h. Biofilms were visualized by epifluorescence and scanning electron microscopy (SEM). Biofilm development occurred at different phases, depending on the incubation conditions. In the reversible adhesion, the cell density of each bacteria was between 1.43 and 6.08 Log₁₀ CFU/cm² (p < 0.05). Moreover, significant reductions in bacteria appeared at 9 °C between 1 and 48 h of incubation. Additionally, the constant multiplication of bacteria in the biofilm occurred at 25 °C between 48 and 180 h of incubation, with increments of 2.08 Log₁₀ CFU/cm² to S. Typhimurium. Population establishment was observed between 48 and 180 h and 180-240 h incubation, depending on the environmental conditions (25 and 9 °C, respectively). For example, in TSB + ME at 25 °C, S. Typhimurium, P aeruginosa, and L. monocytogenes showed no statistical differences in the amounts between 48 and 180 h incubation. The dispersion phase was identified for L. monocytogenes and B. cereus at 25 °C. Epifluorescence microscopy and SEM allowed visualizing the bacteria and extracellular polymeric substances at the different biofilm stages. In conclusion, pathogens and spoilage microorganisms developed monospecies with higher cellular densities than multiespecies biofilms. In multispecies biofilms, the time to reach each biofilm phase varied is depending on environmental factors. Cell count decrements of 1.12-2.44 Log₁₀ CFU/cm² occurred at 48 and 240 h and were most notable in the biofilms developed at 9 °C. Additionally, cell density reached by each microorganism was different, P. aeruginosa and Salmonella were the dominant microorganisms in the biofilms while B. cereus showed the lower densities until undetectable levels.

DETECTION OF ENTEROTOXIN GENES OF Staphylococcus aureus ISOLATES FROM FOOD CONTACT SURFACES IN THE DAIRY INDUSTRY OF JALISCO, MEXICO

Staphylococcus aureus is widely distributed in nature, and two of the main sources of S. aureus contamination in the food industry are food handlers and Food Contact Surfaces (FCS). This pathogen is responsible for outbreaks of foodborne illnesses associated with the consumption of milk and dairy products. The aim of this study was to determine the prevalence of toxin-encoding genes in S. aureus isolates from FCS in the Jalisco dairy industry. The presence of enterotoxin genes was investigated by PCR. In this study, we identify 84 S. aureus isolates. Overall, 35.7% of the isolates tested positive for at least one of the nine studied enterotoxin genes, and 15.4% harbored 2-4 enterotoxin genes. The most predominant genes were sej and sed. This study demonstrates that FCS are a source of contamination for this food rotation and that there is a diversity of enterotoxin genes in S. aureus isolates. Therefore, vigilant food safety practices need to be implemented regarding FCS to prevent foodborne infections and intoxications due to S. aureus contamination.

Resistance of pathogenic and spoilage microorganisms to disinfectants in the presence of organic matter and their residual effect on stainless steel and polypropylene

OBJECTIVES

The effectiveness of disinfectants can vary according to the microorganism, type of residues and surface. The aim of this study was to determine the effectiveness of four disinfectants in the presence of organic matter and their residual effect on stainless steel grade 304 (SS) and polypropylene B (PP-B).

METHODS

The effectiveness of the disinfectants in the presence of meat extract, egg yolk and whole milk was determined according to AOAC and UNE-EN 1040:2015, and the residual effect was determined according to UNE-EN 13697:2015 using approved strains.

RESULTS

The effectiveness of the disinfectants was affected to different degrees depending on the organic matter present. SANICIP Q5 [400μg/mL; fifth-generation quaternary ammonium compound (QAC)] was most effective in the presence of 10% meat extract, whilst SANICIP PAA (200μg/mL; peracetic acid) showed better activity in the presence of 10% egg yolk and whole milk. In the evaluation of residual effect on SS and PP-B, the QAC had a better effect, reducing Listeria monocytogenes ATCC 19111 by 6 Log₁₀ CFU/mL at 24h after its application. Conversely, the disinfectants had no residual effect against Pseudomonas aeruginosa ATCC 15442.

CONCLUSIONS

The antimicrobial activity of the disinfectants tested against pathogenic and spoilage microorganisms was affected according to the type of organic matter present. SANICIP Q5 had a greater residual effect than the other disinfectants evaluated. Moreover, the residual effect of a disinfectant is greater on SS than on PP-B and is dependent on the microorganism tested.

Biofilm formation by Staphylococcus aureus and Salmonella spp. under mono and dual-species conditions and their sensitivity to cetrimonium bromide, peracetic acid and sodium hypochlorite

The aim of this study was evaluated the biofilm formation by Staphylococcus aureus 4E and Salmonella spp. under mono and dual-species biofilms, onto stainless steel 316 (SS) and polypropylene B (PP), and their sensitivity to cetrimonium bromide, peracetic acid and sodium hypochlorite. The biofilms were developed by immersion of the surfaces in TSB by 10 d at 37°C. The results showed that in monospecies biofilms the type of surface not affected the cellular density (p>0.05). However, in dual-species biofilms on PP the adhesion of Salmonella spp. was favored, 7.61±0.13Log10CFU/cm2, compared with monospecies biofilms onto the same surface, 5.91±0.44Log10CFU/cm2 (p<0.05). The mono and dual-species biofilms were subjected to disinfection treatments; and the most effective disinfectant was peracetic acid (3500ppm), reducing by more than 5Log10CFU/cm2, while the least effective was cetrimonium bromide. In addition, S. aureus 4E and Salmonella spp. were more resistant to the disinfectants in mono than in dual-species biofilms (p<0.05). Therefore, the interspecies interactions between S. aureus 4E and Salmonella spp. had a negative effect on the antimicrobial resistance of each microorganism, compared with the monospecies biofilms.

Antimicrobial activity of disinfectants commonly used in the food industry in Mexico

OBJECTIVES

Disinfectants are widely used in food processing environments for microorganism control; their activity can vary according the microorganism and their used in the appropriated concentrations is vital. Hence, the aim of this study was determined the effectiveness and minimum inhibitory concentration (MIC) of 15 disinfectants commonly used in the food industry in Mexico.

METHODS

The antimicrobial activity and the MIC were determined according to AOAC and CLSI, respectively, with approved strains.

RESULTS

Most disinfectants reduced 99.999% of microorganisms in suspension after 30s of contact, so reduction rate corresponded at least 5 Log₁₀. Only for Pseudomonas aeruginosa ATCC 15442, did all disinfectants have 99.999% effectiveness. For the MIC, only the third generation quaternary ammonium compounds (QACs) in acid medium did not have values within the range in which is used in the food industry for Staphylococcus aureus ATCC 25923. In addition, for all disinfectants the MIC at 5min was two to four times greater than the concentration with the same effect at 10min; moreover, in most cases there was no difference in the MIC at 10 and 15min (p>0.05).

CONCLUSIONS

At recommended concentrations, disinfectants had bactericidal activity for at least three of the six microorganisms evaluated. However, the MIC was affected by the exposure time: it was bigger at 5min than at 10min; moreover, in the majority of the cases, it was equal at 10 and 15min; with the results we could have a better understanding of disinfectants use in food processing environments.