<i>Salmonella</i> and Antimicrobial Resistance in Fresh Produce

Contamination of fresh produce with Salmonella may occur during any point from fork to table. It may occur during produce production, harvest, processing, and transportation. Fresh produce has been recognized as a common source for Salmonella since the bacteria has the ability to attach and internalize in produce. Salmonella has been isolated from produce including mangoes, cantaloupe, cucumbers, alfalfa sprouts, and lettuce. Bacteria from fresh produce include a number of opportunistic human pathogens which may be resistant to several antibiotics. Antimicrobial resistant bacteria may have the potential to make their way over to fresh produce through contaminated irrigation water and manure applied to agricultural fields. Salmonella resistant to antibiotics including vancomycin, erythromycin, ampicillin and penicillin has been isolated from vegetables. With the increasing foodborne illness associated with fresh produce, there is a lot of emphasis on good agricultural practices (GAPs) to validate that farms are producing fresh produce in the safest means possible. With proper education and training on GAPs, produce growers will be able limit the occurrence of Salmonella and other foodborne pathogens in fresh produce

Evaluation of drug-resistant Enterobacteriaceae in retail poultry and beef

There has been increasing concern on the emergence of multidrug-resistant foodborne pathogens from foods of animal origin, including poultry. The current study aimed to evaluate antibiotic-resistant Enterobacteriaceae from raw retail chicken/turkey parts (thigh, wings, breast, and ground) and beef meat (ground and chunks) in Middle Tennessee. Resistance of the collected Enterobacteriaceae to a panel of antibiotics was determined by the Kirby-Bauer disk diffusion test. Retail meats were also assayed for the presence of Salmonella spp. and Escherichia coli O157:H7. Two hundred thirty-seven samples representing 95.2% of the total of 249 samples tested were positive for Enterobacteriaceae. The level of contamination with Enterobacteriaceae in raw meats ranged from 3.26 log10 cfu/g to 4.94 log10 cfu/g with significant differences in counts among meat types (P \u3c 0.05). Contamination was significantly greater (P \u3c 0.05) in ground beef, beef chucks, ground chicken, chicken breast, and turkey wings (4.92, 4.58, 4.94, 4.75, 4.13 log10 cfu/g, respectively) than ground turkey and chicken wings (3.26 and 3.26 log10 cfu/g, respectively). Klebsiella oxytoca, Serratia spp., E. coli, and Haffnia alvei were most prevalent contaminants at 27.4, 14.3, 12.1, and 11.4%, respectively. Resistance of the Enterobacteriaceae to antimicrobials was most frequent with erythromycin, penicillin, and ampicillin at 100, 89, and 65.8%, respectively. Few (2.7%) of the Enterobacteriaceae were resistant to chloramphenicol. Salmonella spp., E. coli O157:H7, Morganella morganii, Yersinia enterocolitica, and Vibrio parahemolyticus exhibited multiple drug resistance. This investigation demonstrates that raw poultry and beef are potential reservoirs of antibiotic-resistant Enterobacteriaceae

Atmospheric Cold Plasma Inactivation of Salmonella and Escherichia coli on the Surface of Golden Delicious Apples

The contamination of fruits with human pathogens is a reoccurring concern in the fresh produce industry. Atmospheric cold plasma (ACP) is a potential alternate to customary approaches for non-thermal decontamination of foods. In this study, the efficacy of a dielectric barrier discharge ACP system against Salmonella (Salmonella Typhimurium, ATCC 13311; Salmonella Choleraesuis, ATCC 10708) and Escherichia coli (ATCC 25922, ATCC 11775) was explored. For each bacteria, a two-strain mixture at 8 log10 CFU/ml was spot inoculated on the surface of Golden Delicious apples, air dried, and exposed to ACP at a fixed distance of 35 mm, input power of 200 W for 30, 60, 120, 180, and 240 s. Bacterial inactivation was achieved in all treatment times with highest reduction of 5.3 log10 CFU/cm2 for Salmonella and 5.5 log10 CFU/cm2 for E. coli. Our results showed that reductions were interrelated to exposure time and ranged from 1.3 to 5.3 and 0.6 to 5.5 log10 CFU/cm2 for Salmonella and E. coli, respectively. Salmonella and E. coli significantly decreased (\u3e5.0 log) at 180 and 240 s as compared to 30, 60, and 120 s exposure. Microbial inactivation data was modeled by using Weibull distribution. These findings demonstrate the potential of ACP as a postharvest technology to effectively reduce pathogens on apples, with reference to Salmonella and E. coli

Prevalence and Antimicrobial Resistance of Pathogenic Bacteria in Chicken and Guinea Fowl

This study was conducted to compare the presence and antimicrobial susceptibility of Campylobacter, Salmonella spp., and other enteric bacteria between chickens and guinea fowls. Birds were reared on enclosed concrete floor housing covered with pine wood shavings litter material. Chicken (n = 40) and guinea fowl (n = 40) carcasses, drinking water (10 mL; n = 40), and litter (10 g; n = 40) were aseptically collected randomly from a poultry farm and analyzed within 1 h of collection. Individual pens served as experimental units and were replicated twice. Campylobacter spp., Salmonella spp., and other enterobactericeae were isolated and identified using standard selective media and biochemical tests. Isolates were tested for sensitivity to tetracycline, ampicillin, streptomycin, kanamycin, nalidixic acid, gentamicin, erythromycin, ciprofloxacin, cefoxitin, and colistin using the Kirby-Bauer disk diffusion test. Campylobacter spp. and Salmonella spp. were isolated from 28 and 35% of whole carcass rinses of chickens and from 18 and 23% of whole carcass rinses of guinea fowl, respectively. Although only Salmonella spp. were recovered from drinking water, both Salmonella and Campylobacter spp. were recovered from litter material. Campylobacter upsaliensis was recovered only in the guinea fowl, whereas Klebsiella oxytoca and Enterobacter sakazakii were recovered only in chickens. Although no antibiotic resistance was determined in Campylobacter upsaliensis, most Campylobacter, Salmonella, and Escherichia coli isolates from both chickens and guinea fowl were resistant to antibiotics such as ampicillin, kanamycin, erythromycin, and nalidixic acid

Probiotics and Antimicrobial Effect of Lactiplantibacillus plantarum, Saccharomyces cerevisiae, and Bifidobacterium longum against Common Foodborne Pathogens in Poultry

The probiotic potential and antimicrobial activity of Lactiplantibacillus plantarum, Saccharomyces cerevisiae, and Bifidobacterium longum were investigated against Escherichia coli O157:H7, Salmonella typhimurium and Listeria monocytogenes. Selected strains were subjected to different acid levels (pH 2.5–6.0) and bile concentrations (1.0–3.0%). Strains were also evaluated for their antimicrobial activity by agar spot test. The potential probiotic strains tolerated pH 3.5 and above without statistically significant growth reduction. However, at pH 2.5, a significant (p \u3c 0.05) growth reduction occurred after 1 h for L. plantarum (4.32 log CFU/mL) and B. longum (5.71 log CFU/mL). S. cerevisiae maintained steady cell counts for the entire treatment period without a statistically significant (p \u3e 0.05) reduction (0.39 log CFU/mL). The results indicate at 3% bile concertation, 1.86 log CFU/mL reduction was observed for L. plantarum, while S. cerevisiae, and B. longum growth increased by 0.06 and 0.37 log CFU/mL, respectively. L. plantarum and B. longum demonstrated antimicrobial activity against E. coli O157:H7, S. typhimurium and L. monocytogenes. However, S. cerevisiae did not display any inhibition to any of the pathogens. The results indicate that L. plantarum and B. longum present probiotic potential for controlling E. coli O157:H7, S. and L. monocytogenes in poultry

A comparative analysis of microbial profile of Guinea fowl and chicken using metagenomic approach

Probiotics are live microbial feed supplements that promote growth and health to the host by minimizing non-essential and pathogenic microorganisms in the host’s gastrointestinal tract (GIT). The campaign to minimize excessive use of antibiotics in poultry production has necessitated development of probiotics with broad application in multiple poultry species. Design of such probiotics requires understanding of the diversity or similarity in microbial profiles among avian species of economic importance. Therefore, the objective of this research was to establish and compare the microbial profiles of the GIT of Guinea fowl and chicken and to establish the microbial diversity or similarity between the two avian species. A metagenomic approach consisting of the amplification and sequence analysis of the hypervariable regions V1-V9 of the 16S rRNA gene was used to identify the GIT microbes. Collectively, we detected more than 150 microbial families. The total number of microbial species detected in the chicken GIT was higher than that found in the Guinea Fowl GIT. Our studies also revealed phylogenetic diversity among the microbial species found in chicken and guinea fowl. The phylum Firmicutes was most abundant in both avian species whereas Phylum Actinobacteria was most abundant in chickens than Guinea fowls. The diversity of the microbial profiles found in broiler chickens and Guinea fowls suggest that the design of effective avian probiotics would require species specificity

Prevalence of Multidrug-Resistant Foodborne Pathogens and Indicator Bacteria from Edible Offal and Muscle Meats in Nashville, Tennessee

This study investigated the prevalence of antimicrobial-resistant bacteria in retail edible offal and muscle meats in Nashville, Tennessee. A total of 348 retail meats (160 edible offal and 188 muscle) were analyzed for Salmonella enterica serovar, Campylobacter, Escherichia coli, E. coli O157:H7, and enterococci. Bacteria was identified using biochemical and PCR methods. Salmonella enterica serovar (4.4% and 4.3%), Campylobacter (1.9% and 1.1%), E. coli (79.4% and 89.4%), and enterococci (88.1% and 95.7%) was detected in offal and muscle meats, respectively. Chicken liver (9.7%) was most frequently contaminated with Salmonella enterica serovar, followed by ground chicken (6.9%) and chicken wings (4.2%). No Salmonella enterica serovar was detected in beef liver, beef tripe, and ground beef. The prevalence of Campylobacter was 6.9%, 2.3%, and 1.4% in beef liver, ground beef, and ground chicken, respectively. None of the meats were positive for E. coli O157:H7. Resistance of isolates was significantly (p \u3c 0.05) highest in erythromycin (98.3%; 99.1%), followed by tetracycline (94%; 98.3%), vancomycin (88.8%; 92.2%) as compared to chloramphenicol (43.1%; 53.9%), amoxicillin/clavulanic (43.5%; 45.7%), and ciprofloxacin (45.7%; 55.7%) in offal and muscle meats, respectively. Imipenem showed the lowest resistance (0%; 0.9%). A total of 41 multidrug-resistant patterns were displayed. Edible offal could be a source of antibiotic-resistant bacteria