Mean Total Viable Count Research Articles

Comparative study on the microbial load of Gari, Elubo- isu and Iru in Nigeria

Microbiological investigation was carried out on the safety of three locally fermented foods (gari, elubo-isu and iru). Twelve different samples each of three locally fermented food products- namely- gari, elubi-isu and iru were collected from the central markets at three different states in Nigeria (Ijebu-Igbo Central Market, Ogun State; Bodija Market, Ibadan, Oyo State and Garki Central Market, Abuja) and evaluated microbiologically. Various types of microorganisms were isolated from the three locally fermented food products (gari, elubo-isu and iru), and characterized. Both bacteria and fungi were isolated from these evaluated fermented food products. The mean total bacterial count in the samples of gari,elubo-isu and iru were 13.1 x 104, 11.4 x 105 and 9.5 x 106 cfu/ g, respectively. Also the mean total viable count of mould was 1.4 x104, 3.4 x 105 and 7.4 x 106 cfs/g, respectively. Bacteria isolated from gariinclude Actinomyces sp.,Bacteriodes sp.Corynebacterium sp.,Pseudomonas sp., Lactobacillus andLeuconostoc sp., while the isolated moulds from gari include Culicidosporagravida, Diplococcium spicatum, Geotrichum candidum, Passalorabacilligera,Scolecotrichum graminis, Tallospora aspera, and Varicosporium sp. Bacteria isolated from elubo-isu include-;Lactob sp., Streptococcus sp. andListeria sp., while the isolated moulds were Articulospora inflate, Aspergillus niger,Aspergillus rapens, Aspergillus flavus and Lemonniera aquatica. Also, the bacteria isolated from iru were Bacillus sp., Pediococcus sp., Streptococcus sp. andLactobacillus sp., while the mould isolated from iru were Aspergillus fumigatus,Rhizopus stolonifer and Triscelophorus monosporus. It was concluded that the low microbial counts recorded for the evaluated fermented food products are tolerable and, thus, still safe for human consumption. Key words: Fermented foods, bacteria, fungi, safety.

Ratio between carcass-and skin-microflora as an abattoir process hygiene indicator

In two abattoirs, each slaughtering both cattle and pigs, 100 cattle and 100 pigs were randomly selected and sampled. From each animal, two samples were taken: a) immediately after sticking of bovines or stunning of pigs, approximately 2000 cm 2 hide (cattle) or 1500 cm 2 skin (pigs) areas were sponge-swabbed; and b) at the end of slaughter line but before chilling, the same areas on corresponding dressed carcasses were sponge-swabbed. In each swab-sample (400 in total), total viable count (TVC) and Enterobacteriaceae count (EC), as well as Escherichia coli O157 (in cattle) or Salmonella (in pigs) occurrence, were determined and used to assess process hygiene in the abattoirs. The results indicated that simply fitting mean TVC and/or EC on final carcasses into an acceptable, marginal or unacceptable process hygiene category (according to current microbiological EU process hygiene criteria) did not enable characterisation of each process with respect to its ability to reduce the transfer of incoming microbial loads (i.e. on skins) onto dressed carcasses. On the other hand, determining the ratio between mean TVC and/or EC on final carcasses and those on corresponding skins enabled more precise assessment of the hygiene of each abattoir process, as well as more reliable differentiation between abattoirs. On the other hand, occurrence of E. coli O157 in cattle or Salmonella in pigs (skins and/or carcasses), being dependant on varying factors including those on-farm/pre-abattoir, did not appear to be very useful for characterisation of the process hygiene but is valuable for the purposes of consumer exposure assessment and pathogen reduction.

Estimation of bacterial contamination of indigenous bovine carcasses in Khartoum (Sudan)

The study was conducted to evaluate the bacteriological contamination in indigenous cattle in slaughterhouse, Khartoum State, during April 2008 - June 2008. A total of 384 swab samples were collected from 32 carcasses for identification of the isolates and bacterial total viable counts (TVCs). The mean total viable count of bacteria after skinning, evisceration and washing operations at shoulder site were, 3.03 ± 0.15, 2.73 ± 0.02 and 2.79 ± 0.10 log10 CFU/cm2, in the neck site were 3.65 ± 0.02, 3.42 ± 0.02 and 3.72 ± 0.02 log10 CFU/cm2 and in brisket site were 3.1 ± 0.14, 3.71 ± 0.04 and 3.65 ± 0.02, respectively with statistically significant difference (P < 0.05). In addition, in the rump site, the TVCs in these operations were 3.24 ± 0.02, 2.88 ± 0.02, and 3.18 ± 0.03 log10 CFU/cm2 in three points of operation with statistically significant difference (P < 0.05). Also, there were statistically significant difference (P < 0.05) in TVCs between knives and worker hands during the three operations. Twelve species of bacteria were isolated and the highest average prevalence wasStaphylococcus arueus 10.54%, Klebsella spp. 10.12% and Escherichia coli 8.86%. Key words: Bovine carcass, bacterial contamination, slaughterhouse.

A Baseline Survey of the Microbiological Quality of Chicken Portions and Carcasses at Retail in Two Australian States (2005 to 2006)

Raw poultry products were purchased from the retail market place in two Australian states, New South Wales (n = 549) and South Australia (n = 310). The products sampled on a proportional volume basis were chicken portions with the skin off or skin on, in bulk or tray packs, and whole carcasses. They were collected from butcher shops, supermarkets, and specialty stores from urban areas during the winter (2005) and summer (2006) months. The samples were analyzed to determine the prevalence and concentration of Escherichia coli, Salmonella, and Campylobacter spp. in addition to total viable counts. Salmonella was found in 47.7 and 35.5% of retail chicken samples (35.3 and 21.9% were the less virulent Salmonella Sofia), at mean counts of −1.42 and −1.6 log MPN/cm2 in New South Wales and South Australia, respectively. Campylobacter was found in 87.8 and 93.2% of samples at mean counts of 0.87 and 0.78 log CFU/cm2, respectively. In both states in both seasons, the mean total viable count was 5 log CFU/cm2. On whole birds, E. coli was detected in all winter samples and on 92.9 and 85.7% of summer samples in New South Wales and South Australia, respectively; the log of the geometric mean per square centimeter was 0.5 in winter and slightly lower in summer. On chicken portions, E. coli was detected in around 90% of winter samples in both states, and in summer on 75.1 and 59.6% of samples in New South Wales and South Australia, respectively. The log of the geometric mean CFU per square centimeter for E. coli was 0.75 and 0.91 in winter, and 0.66 and 0.5 in summer in New South Wales and South Australia, respectively.

Microbiological evaluation and antibiotic susceptibility of dental unit water systems in general dental practice

The microbial quality of water in a dental unit water systems (DUWS) is of considerable importance because patients and dental staff are regularly exposed to water and aerosol generated from the dental units. The objective of this study was to evaluate the 20 DUWS in general dental practices and to determine the antibiotic susceptibility of the colonizing bacteria. Three water and one biofilm samples from each DUWS were investigated for total viable count (TVC), oral streptococci, Pseudomonas spp., Enterobacteria, Candida albicans and Legionella pneumophila. A total of 44 morphologically different colonies were obtained from water samples and 20 types of colonies (45.5%) could be identified using API test strips. The mean TVC values were 4.36 log CFU ml(-1) for source waters, 4.95 log CFU ml(-1) for 3-in-1 syringe samples, 4.91 log CFU ml(-1) for air rotor samples and 3.66 log CFU cm(-2) for biofilm samples. Susceptibilities of the isolates were tested against piperacillin, ampicillin, ceftazidime, meropenem, gentamicin, tetracycline, ofloxacin and chloramphenicol by using microdilution method according to NCCLS. The meropenem and ofloxacin have shown the broadest spectrum against to the tested isolates. The study emphasizes the need for effective mechanisms to reduce the microbial contamination in DUWS, and highlights the risk for cross-infection in general dental practice.

English

The microbiological safety of three locally fermented foods (gari, lafun and ogiri) was investigated in this work. Ten different samples each of the fermented foods were collected at the central market (Oja Oba). The mean total bacterial count in the samples of gari, lafun and ogiri were 14.3 x 104, 13.2 x 105 and10.2 x106 cfu/g, respectively. Also the mean total viable count of mould was 1.6 x 104, 3.7 x 105 and 8.2 x 106 cfs/g, respectively. Bacteria isolated from gari include Corynebacterium species, Lactobacillus species, Bacteriodes species, Pseudomonas species and Actinomyces species while the isolated moulds from gari include Scolecotrichum graminis, Tallospora aspera, Passalora bacilligera, Varicosporium sp., Culicidospora gravida and Diplococcium spicatum. Bacteria isolated from lafun include; Streptococcus sp., Lactobacillus species and Listeria species while the isolated the isolated moulds were Articulospora inflate, Aspergillus niger, Aspergillus rapens, Aspergillus flavus and Lemonniera aquatica. Also, the bacteria isolated from ogiri were Bacillus sp., Pediococcus sp., Streptococcus sp. and Lactobacillus sp. while the mould isolated from ogiri were Rhizopus stolonifer, Aspergillus fumigatus and Triscelophorus monosporus. Even though some potential pathogenic bacteria like Listeria and Bacillus were isolated from the fermented foods, the low count recorded for them is not enough to establish any health risk.

Microbiological quality of Australian sheep meat in 2004

The third national baseline microbiological survey of Australian sheep carcases and frozen boneless sheep meat was conducted in 2004. Carcases ( n = 1117) sampled at 20 slaughter establishments were found to have a mean log total viable count (TVC, 25 °C) of 2.28 cfu/cm 2 and Escherichia coli was isolated from 43.0% carcases with a mean log 0.03 cfu/cm 2 on positive samples. In samples from 10 boning (fabrication) plants ( n = 560) the mean log TVC for frozen boneless sheep meat was 1.85 cfu/g and the mean log count for the 8.2% of samples with detectable E. coli was 1.39 cfu/g. E. coli O157:H7 was isolated from 6/1117 carcases and from 1/560 boneless samples. Salmonella was isolated from 0/1117 carcases and from 3/560 samples of boneless product. Campylobacter sp. were isolated from 4/1117 carcases and from 1/560 boneless samples. Coagulase positive staphylococci were isolated from 23.4% to 32.7% of carcases and boneless sheep meat samples, respectively, with positive samples having a mean log count of 0.93 cfu/cm 2 and 1.14 cfu/g, respectively. The low level of bacteria described here is consistent with a very low risk to human health due to bacterial hazards in Australian sheep meat.

The effects of surface steam treatment on bacterial reduction and storage of beef primals and retail cuts

Beef primals and retail joints were rapidly heated and cooled using steam condensation and evaporation heat transfer processes. Treatments of beef primals to 100 or 120 °C showed no significant differences. After 3 weeks of vacuum-packed storage at 0 °C, mean total viable count (TVC) and enterobacteriaceae counts for treated primals were approximately 1 log 10 cfu cm −2 lower than for un-treated primals. Levels were similar after 6 weeks of vacuum-packed storage. The effects of a second treatment on retail joints cut from treated and un-treated primals that had been stored in vacuum packs for 3 weeks showed TVC and enterobacteriaceae counts for treated joints were approximately 1 log 10 cfu cm −2 lower than for un-treated joints after 4 and 8 days of over-wrapped storage. The results suggest the steam decontamination treatment used can remove small but significant ( p < 0.05) numbers of bacteria from the beef surface.

Microbiological Quality of Chilled Beef Carcasses in Northern Ireland: A Baseline Survey

To standardize the assessment of the hygienic quality of beef carcasses in Northern Ireland (NI) abattoirs, swabbing techniques were evaluated. Six materials, including two commercially produced swabs, were compared for their ability to recover spoilage and pathogenic bacteria and for their ease of use as carcass swabs. A sponge retailed for domestic use was selected on the basis of efficiency of recovery of microorganisms, ease of use, and cost. On sample carcasses, 1,000 cm2 of the brisket was swabbed, since this site is normally readily contaminated. For 9 months, 420 carcasses in seven of the nine European Union–approved abattoirs in NI were sampled while in the chiller (24 to 48 h after kill). Total viable count (TVC), yeasts and molds, and Enterobacteriaceae were enumerated after incubation at 22 (48 h) and 37°C (48 h), and the results were expressed as log CFU/cm2. The mean TVC results at 22 and 37°C were 2.80±0.70 and 2.75 ± 0.64, respectively. Although 63% of samples had yeasts that grew at 22°C, only 35% were positive at 37°C. The respective mean yeast counts were 1.12±0.59 and 0.46 ± 0.51. Enterobacteriaceae were present in 15% of samples at 22°C and 21% of samples at 37°C. The mean counts for positive samples were 0.41±0.37 and 0.40 ± 0.30, respectively. Molds were found in less than 4% of samples. Given that the brisket is normally one of the most heavily contaminated parts of the carcass, these results suggest that good hygienic practices are in operation in NI abattoirs. The results also enabled the abattoirs with the cleanest carcasses to be identified, hence permitting best practices to be found.

Aerobiology of a High-Line Speed Cattle Abattoir

The operation of the high-line speed cattle abattoir studied follows a plant-created hazard analysis and critical control point (HACCP) plan that is recognized by the Canadian Food Inspection Agency. Measurement of bioaerosols is not a part of this plan. In this study CFUs in air of selected abattoir processes were enumerated after impinging air onto tryptic soy agar plates with a slit air sampler for 10 to 20 min. The total viable count (TVC) per liter of air was calculated for each sample following incubation at 30°C for 24 h. Monthly samples were collected on the hide removal floor and the carcass dressing floor from March 1998 to April 1999. Mud tag, dirt, and wetness of incoming hides were scored subjectively on the hide removal floor. The other processes were sampled in 3 separate months. The TVC at two locations on the hide removal floor (center of hide removal floor [CHF] and top of hide puller [THP]) had a strong association to each other (r = 0.84; P < 0.001). The mean TVC at the CHF and THP was 10.0 and 11.5, respectively, and the TVC for individual samples ranged from 2 to 42 at these locations. The TVC means for all the other processes ranged from 0.01 to 0.7. Tag and TVC on the hide removal floor had a different seasonal distribution with TVC being highest in the warm months (April to October 1998) and lowest for November to April 1999. No significant relations between TVC and the dirt and wetness variables were evident for the CHF and THP locations on the hide removal floor. It was concluded that the control of aerosols in the hide removal floor should be treated as a critical control point in the HACCP plan.

Relevance of abattoir hygiene assessment to microbial contamination of British beef carcases.

Eleven beef abattoirs were visited, each on five separate occasions. On each occasion, an audit was carried out according to the official Hygiene Assessment System (HAS) and 10 carcases were sampled at four different sites to assess total viable counts and counts of presumptive coliform bacteria. The HAS scores ranged from 11 to 84 (maximum 100), and the logarithmic mean total viable counts for all sampling sites on each batch of carcases varied between 1.98 and 4.14 colony forming units/cm2. The mean prevalence of coliform contamination ranged from 0 to 85 per cent. There was a significant negative correlation (P < 0.001) between the mean HAS scores and the mean total viable count for each abattoir, but not between the HAS scores and the numbers of coliforms. Within the HAS, the mean scores for all five categories, before weighting, showed a significant correlation with the mean total viable count (P < 0.001); however, the categories concerned with slaughter and dressing, and personnel and practices were of most value in determining trends in carcase contamination. A new advisory classification is proposed for levels of microbial contamination on beef carcases.

Microbiological survey of five poultry processing plants in the UK

1. Neck skin samples were taken from chickens and turkeys at all the main stages of processing to monitor changes in total viable count (TVC) and counts of coliforms and pseudomonads. 2. Processing reduced TVC by up to 100-fold. Geometric mean counts after packaging were log10 4.4 to 5.3 CFU/g whilst corresponding counts of coliforms were 2.7 to 3.8 CFU/g. 3. Increases in mean TVC or coliforms as a result of either defeathering or evisceration did not exceed 0.6 log. 4. Pseudomonads represented only a minor fraction of the initial microflora of the bird and were often reduced by scalding to a figure which could not be detected by direct plating of samples; however, subsequent contamination resulted in means between log10 2.9 and 4.0 CFU/g for packaged carcases. 5. Although Staphylococcus aureus was readily isolated from defeathering equipment, mean counts from defeathered carcases were always below log10 3.0 CFU/g.

Putative periodontal pathogens on titanium implants and teeth in experimental gingivitis and periodontitis in beagle dogs.

The microflora around titanium implants and teeth in 4 beagle dogs was analyzed in order to follow the longitudinal development from healthy conditions to experimental gingivitis and periodontitis. A 2-month plaque control program was performed to establish healthy conditions on titanium implants and control teeth (baseline, day 0). Subgingival bacterial samples and radiographs were obtained. The plaque control was ceased and all measurements were repeated on day 21 (gingivitis). A new period of plaque control was initiated to re-establish healthy conditions (day 49). A cotton ligature was placed subgingivally around the implants and the control teeth to induce tissue breakdown. The ligatures were removed on day 91. The study was completed with registrations on day 121 (periodontitis). No significant microbiological difference was found between titanium implants and teeth in healthy conditions and in gingivitis and periodontitis. The mean total viable count increased 10 times on implants as well as on teeth. Streptococci were dominating at baseline: 40.2% on implants and 60.6% on teeth and decreased in gingivitis to 11.7% and 5.4%. When periodontitis had developed, the proportion of streptococci was < 1%. At baseline few Porphyromonas gingivalis and Prevotella intermedia were detected. They increased at gingivitis to 37.4% and 21.0%; when periodontitis developed, they comprised about 25.0%. Microbial colonization and establishment on titanium implants with healthy gingiva, experimental gingivitis and periodontitis follow the same pattern as on teeth.

The use of DNA probes to examine the distribution of subgingival species in subjects with different levels of periodontal destruction.

The present investigation examined the distribution of 14 subgingival species at a total of 2299 sites in 90 subjects with different levels of periodontal destruction. Subgingival plaque samples taken from the mesial aspect of each tooth were anaerobically dispersed, diluted and plated on non selective media. After anaerobic incubation, colonies were lifted to nylon filters and specific species detected using digoxygenin-labeled whole chromosomal DNA probes. The mean total viable count for all sites in all subjects was 8.3 x 10(6). The probes accounted for an average of 27.8% of the total viable count. The % of subjects in which each species was detected was as follows; V. parvula, 98; B. intermedius I, 98; S. sanguis II, 96; B. intermedius II, 95; C. ochracea, 94; B. gingivalis, 91; S. sanguis I, 85; W. recta, 83; F. nucleatum ss. vincentii, 82; S. intermedius, 80; B. forsythus, 76; P. micros, 74; A. actinomycetemcomitans serotype a, 62 and A. actinomycetemcomitans serotype b, 52. The % of sites colonized by each of the 14 test species varied considerably within different subjects. The median number of sites colonized by different species ranged from 3.6% for A. actinomycetemcomitans serotype b to 43.5% for V. parvula. In half the subjects, the mean % of the total viable counts for each of the test species was less than 4%. When subjects were divided on the basis of % of sites at baseline with greater than 3 mm attachment loss, the 14 probes accounted for 29.9% of the microbiota in the localized disease group and 25% in the widespread disease group.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of endodontic procedures on the population of viable microorganisms in the infected root canal

To determine quantitatively the microflora of the infected root canal, 20 freshly extracted pulpless human teeth were treated endodontically and then crushed, cultured, and evaluated. In addition, a comparison was made with root canal cultures obtained from paper point inoculations. After mechanical instrumentation and irrigation of the root canal, the mean total viable count of microorganisms obtained from solid agar plates was approximately 200 per tooth. After mechanical instrumenta tion, irrigation, and medication with 35% camphorated parachlorophenol, the count was reduced to approximately 50 per tooth. Negative root canal cultures did not necessarily indicate sterility of the root canal.