Mean Enterobacteriaceae Counts Research Articles

Descriptive and categorical analyses of live animals imported into Nigeria through an international airport and their enterobacterial load

Introduction: Globalization, international trade, and the increase in human and animal populations has enhanced the spread of infectious pathogens across countries. The volume, sources, species, enterobacterial load, and Enterobacteriaceae bacteria of live animals imported through Murtala Muhammed International Airport into Nigeria were investigated. Methods: Data of imported animals from various continents into Nigeria between years 2010 and 2016 were retrieved from Department of Veterinary and Pest Control Services. Faecal samples were collected from dogs and cats imported from April to July 2017 for isolation and identification of Enterobacteriaceae bacteria, and enterobacterial load assessment using MacConkey agar, Nutrient agar and biochemical tests. Data were analysed using descriptive statistics and Chi-square at p < 0.05. Results: A total of 6,349 (median = 676; range: 362-1666) animals were imported. Africa had the largest volume (55.7%), Europe (28.0%) and Oceania lowest (0.1%). Canine (dogs) and feline (cats) (59.9%), caprine and ovine (12.1%), bovine (11.5%), porcine (10.2%) and equine (6.2%) were imported. Continent of origin (χ2= 21.63, p < 0.0001) and species (χ2 = 1200.00, p < 0.0001) were significantly associated with volume of importation. Mean Enterobacteriaceae Counts were 18.126±0.84×107 and 3.855±0.53×107 CFU/gram for dogs and cats, respectively. Escherichia coli, Proteus, Shigella, Citrobacter and Klebsiella species were isolated. Significance: Live animals, mostly dogs and cats imported frequently from Africa and Europe into Nigeria through the airport may constitute a risk of introducing infectious and zoonotic pathogens into the country. Animals imported into Nigeria should be regularly quarantined and assessed microbiologically to ensure disease prevention.

Prevalence of Multidrug-Resistant Bacteria from U.S.-Grown and Imported Fresh Produce Retailed in Chain Supermarkets and Ethnic Stores of Davidson County, Tennessee

The aim of this study was to determine whether U.S.-grown and imported fresh produce retailed in ethnic stores and chain supermarkets was a reservoir of antibiotic-resistant bacteria. A total of 360 (129 imported and 231 U.S.-grown) samples of fresh produce were purchased from retail stores and analyzed for Enterobacteriaceae , including three pathogenic bacteria ( Escherichia coli O157:H7, Shigella , and Salmonella ), using standard methods. Presumptive pathogenic isolates were confirmed using PCR. The mean Enterobacteriaceae counts for imported produce were 6.87 ± 0.15 log CFU/g and 7.16 ± 0.11 log CFU/g in ethnic stores and chain supermarkets, respectively. For U.S.-grown produce, the contamination levels were at 8.35 ± 0.17 log CFU/g and 7.52 ± 0.13 log CFU/g in ethnic stores and chain supermarkets, respectively. Salmonella (0 and 0.3%), Shigella (1.7 and 0.6%), E. coli (3.1 and 1.4%), Enterobacter (9.4 and 8.6%), Klebsiella (6.7 and 0.6%), and Serratia (5.8 and 1.4%) were detected in produce from ethnic stores and chain supermarkets, respectively. None of the samples were positive for E. coli O157:H7. Regarding distribution by produce type, leafy vegetables had a significantly (P < 0.05) higher prevalence of Enterobacteriaceae (19.2%) than the other types, followed by root vegetables (6.4%), tomatoes (5.6%), and fruits (3.9%). Antibiotic-resistant Salmonella , Shigella , E. coli , Enterobacter , Klebsiella , and Erwinia bacteria were also isolated from fresh produce. The frequencies of vancomycin resistance (98.1 and 100%) were significantly higher (P < 0.05) than the frequencies of ampicillin resistance (42.3 and 72.9%) for imported and U.S.-grown produce, respectively. Despite the increased attention to the role of imported produce as a source of antimicrobial resistance, this study indicates that U.S.-grown produce is also contaminated with antibiotic-resistant bacteria. Good agricultural practices on the farms and washing of fresh produce before consumption are greatly recommended to avoid possible public health hazards.

SUBSISTENCE OF SPECIFIC SPOILAGE ORGANISMS IN COMMINUTED MEAT PRODUCTS AT RETAIL LEVEL

Comminuted meat products are important sources for protein, fat, minerals and other nutrients. The specific spoilage organisms association of meat products should be periodically monitored in parallel with the changes in the economic and social live style. Therefore, a total of 75 random frozen samples of comminuted meat products (25 each of hamburger, minced beef and sausage) commercially produced and procured at the retail level in Ismailia city were examined for total aerobic, psychrophilic, proteolytic and Enterobacteriaceae counts. The percentage of proteolytic bacteria in hamburger, minced beef and sausage samples were 84, 68 and 80%, respectively, and for Enterobacteriacae bacteria were 60, 48 and 56%, respectively. The mean aerobic counts of hamburger, minced beef and sausage samples were 4.9 x104, 1.8 x105 and 3.8 x105 CFU/g, respectively, while the mean psychrophilic counts were 4.1 x105, 9.5 x104 and 1.9 x105 CFU/g, respectively, and the mean proteolytic counts were 2.1 x104, 1.3 x104 and 3.4 x104 CFU/g, respectively. Finally, the mean Enterobacteriaceae counts were 5.8 x103, 2.6 x103 and 7.1 x103 CFU/g, respectively. The highest frequency of psychrophilic microorganisms was Micrococcus roseus, whereas, the highest frequency of proteolytic microorganisms was Pseudomonas cepacia. It could be concluded that the microbial content of meat products at the retail level in Ismailia city confirmed the original microbial contamination of raw meat as well as the additional contamination occurred during processing. Application of Hazard Analysis and Critical Control Point (HACCP) systems in meat plants aids in improve the microbial quality of the comminuted meat products.

Evaluation of Enterobacteriaceae in the powdered milk production chain using both traditional (ISO 21528:2) and rapid (3M™ Petrifilm™) methods

This study sought to evaluate the presence of Enterobacteriaceae in several points of the powdered milk production chain (raw milk, pasteurized milk, powdered milk, and swabs of equipment and the hands of manipulators). There was a similarity between the ISO 21528:2 and the 3M Petrifilm Enterobacteriaceae Plate (EB) methods in all the samples tested. Enterobacteriaceae counts in raw milk were higher (p < 0.001) than in other samples. Bacterial counts were similar for both sampling methods (p < 0.01), except for raw milk. This observation highlights the fact that these samples were the main source of Enterobacteriaceae in the plant and reinforces the efficacy of the thermal treatment to reduce them. The mean Enterobacteriaceae counts were 5.68 and 5.83 log CFU/mL in raw milk and 0.45 and 0.97 log CFU/mL in powdered milk for the 3M Petrifilm EB plate and ISO 21528:2 methods, respectively. The industry used in this study can be considered a potential exporter of milk powdered to the European Union in terms of Enterobacteriaceae counts.

Prevalence, numbers and characteristics of Salmonella spp. on Irish retail pork

Salmonella is a common contaminant of raw pork and represents a public health risk. Both qualitative and quantitative data on Salmonella in pork at retail are required for assessment of consumer exposure to the pathogen. Pork samples ( n = 500) were collected at random from butchers' shops and supermarkets in the Republic of Ireland between January and November, 2007 and examined for prevalence and numbers of Salmonella using a PCR screen followed by cultural examination of positive samples. Salmonella numbers were assessed using a three tube most probable number (MPN) technique. Any Salmonella recovered were characterised by serotype, phage type and antibiogram, and subtyped by pulsed-field gel electrophoresis (PFGE). Enterobacteriaceae were also enumerated to see if there was a correlation between the Salmonella status of the pork and hygiene levels at retail outlets. Salmonella spp. were detected on 13/500 (2.6%) pork cuts at numbers between < 0.03 and 2.10 MPN/g. The mean Enterobacteriaceae counts was 3.12 log 10 CFU/g (range − 0.26–6.52 log 10 CFU/g). Salmonella Typhimurium was the most common serotype and the majority of isolates were multi antibiotic resistant. PFGE analysis showed evidence of persistence of some strains, with an S. Typhimurium U310 recovered from a pork abattoir being identical (100%) to a strain found a year later in a sample from a retail outlet. There was also evidence of cross contamination of Salmonella isolates between samples. There was a direct association between Salmonella contamination of pork and Enterobacteriaceae numbers, which indicates the need for good hygiene practices at retail for control of this pathogen.

Detection of Fecal/Ingesta Contaminants on Poultry Processing Equipment Surfaces by Visible and Near-Infrared Reflectance Spectroscopy

Visible and near-infrared (NIR) spectra and samples for laboratory microbial analysis were acquired of fecal contaminants, ingesta contaminants, and bare processing equipment surfaces (rubber and stainless steel) in a commercial poultry processing plant. Spectra were analyzed in the visible region of 450 to 748 nm and the NIR region of 920 to 1680 nm and microbial sampling for Enterobacteriaceae counts (EBC) was conducted for 82 fecal contaminant samples, 59 ingesta contaminant samples, 40 bare rubber belt areas, and 40 bare stainless steel areas. Two-wavelength band ratios in the visible and NIR regions were selected for separating contaminants from equipment areas. Principal component analysis (PCA) was performed to analyze the spectral data set and 2-class soft independent modeling of class analogy (SIMCA) models were developed for comparison with band ratio classification. Fecal and ingesta contaminants were difficult to separate from each other but both were easily differentiated from the equipment areas. The visible ratio using 518 and 576 nm correctly classified 100% of contaminant samples and 92.5% of equipment area samples. The NIR ratio using 1565 and 1645 nm correctly classified 100% of the contaminant samples and 95% of the equipment area samples. Microbiological analysis found the highest EBC levels for fecal contaminants; mean EBC for ingesta contaminants was significantly lower than that for fecal contaminants. The high EBC levels for fecal contaminants indicate that these contaminants should be targeted for spectral-based detection methods for sanitation monitoring and verification purposes; although their EBC levels are significantly lower, ingesta contaminants should also be included due to difficulty of separation from fecal contaminants.

Microbiological Quality and Safety of Ready-to-Eat Street-Vended Foods in Johannesburg, South Africa

Fifty-one ready-to-eat street foods, 18 dishwater, and 18 surface swab samples were collected from six vendors in Johannesburg, South Africa. Food temperatures were recorded at the time of sampling. Standard methods were used to determine aerobic plate counts (APCs), spore counts (SCs), and Enterobacteriaceae counts (ECs) for food samples as well as coliform counts (CCs) for water and swab samples. In addition, Petrifilm Escherichia coli count (PC) plates were used for the enumeration of coliforms in food, water, and swab samples. The presence of selected foodborne pathogens in the food samples as well as the presence of nonpathogenic E. coli 1 (in food and water samples) was also tested for. Predominant colonies isolated from APC plates were characterized to the genus level. Holding temperatures for cooked meats and gravies ranged from 42.0 to 94.0°C, and those for uncooked salads ranged from 29.0 to 39.0°C. Mean APC values of 3.4 (±0.4) log CFU/g, 4.0 (±1.2) log CFU/ml, and 2.1 (±0.4) log CFU/25 cm2 were obtained for food, water, and swab samples, respectively. Mean SC values of 1.6 (±0.2) log CFU/g and 1.5 (±0.3) log CFU/25 cm2 were obtained for food and swab samples, respectively. A mean EC value of 2.0 (±0.4) log CFU/g for food samples and mean CC values of 2.5 (±0.3) log CFU/ml and 1.3 (±0.3) log CFU/25 cm2 for water and swab samples, respectively, were determined. Mean PC values of 1.6 (±0.1) log CFU/g, 1.9 (±0.6) log CFU/ml, and 1.4 (±0.4) log CFU/25 cm2 were determined for food, water, and swab samples, respectively. Bacillus cereus was detected in 22%, Clostridium perfringens in 16%, Salmonella spp. in 2%, and E. coli (non-O157:H+) in 2% of the 51 food samples. E. coli was found in 14 water samples (78%) and in 3 food samples (6%). Campylobacter spp., Listeria monocytogenes, Staphylococcus aureus, Vibrio cholerae, and Yersinia enterocolitica were also tested for in the food samples, but they were not detected. The 340 isolates obtained from APC plates for food, water, and swab samples were predominantly Bacillus spp., Micrococcus spp., and Staphylococcus spp. for all three sample types. It was concluded that the foods analyzed in this study were of acceptable quality and safety.