Foodstuffs. Detection of irradiated food using Direct Epifluorescent Filter Technique/Aerobic Plate Count (DEFT/APC). Screening method

2002 ◽  
Keyword(s):  
Screening Method ◽  
Plate Count ◽  
Filter Technique ◽  
Irradiated Food ◽  
Aerobic Plate Count ◽  
Direct Epifluorescent Filter Technique

Microbiological Screening Method for Indication of Irradiation of Spices and Herbs: A BCR Collaborative Study

1993 ◽  
Vol 76 (3) ◽  
pp. 674-681 ◽  
Author(s):  
Gun Wirtanen ◽  
Anna-Maija Sjöberg ◽  
Flemming Boisen ◽  
Timo Alanko ◽  
◽  
...  
Keyword(s):  
Collaborative Study ◽  
Screening Method ◽  
Conclusive Evidence ◽  
Plate Count ◽  
Heat Treated ◽  
Relative Standard ◽  
Plate Count Method ◽  
The Difference ◽  
Aerobic Plate Count ◽  
Direct Epifluorescent Filter Technique

Abstract A BCR1 collaborative study was conducted with a microbiological screening method based on the combined use of the direct epifluorescent filter technique (DEFT) and the conventional aerobic plate count method (APC) for detection of irradiation of spices and herbs. Collaborative samples of whole allspice, whole and powdered black peppers, whole white pepper, paprika powder, cut basil, cut marjoram, and crushed cardamom irradiated with doses of 0, 5, and 10 kGy were analyzed by 8 laboratories. The total number of the collaborative samples, with arbitrarily labeled codes, was 192. The percentage of acceptable results was 95.5%. The identification of irradiated from nonirradiated spices and herbs was analyzed statistically by using explorative techniques. The average values of the differences between DEFr and APC in samples irradiated with doses of 5 and 10 kGy were 5.1 and 6.1 logarithmic units, respectively. The differences between DEFT and APC generally increased to at least 3.5 logarithmic units, whereas the difference in the case of unirradiiated spices was insignificant. However, conclusive evidence of irradiation relies on the knowledge that the sample was not fumigated or heat treated. The reproducibility relative standard deviations for the differences were 12.3,19.9, and 20.7% with the closes of 10 and 5 kGy and for unirradiated samples, respectively, indicating acceptable variabilities among laboratories. Received

Determination of Viable Bacterial Populations in Raw Milk within 20 Minutes by Using a Direct Epifluorescent Filter Technique

1997 ◽  
Vol 60 (7) ◽  
pp. 874-876 ◽  
Author(s):  
CLAUDE P. CHAMPAGNE ◽  
NANCY J. GARDNER ◽  
JULIE FONTAINE ◽  
JACQUES RICHARD
Keyword(s):  
Raw Milk ◽  
Plate Count ◽  
Bacterial Populations ◽  
Filter Technique ◽  
Milk Samples ◽  
Standard Plate ◽  
Plate Counts ◽  
Direct Epifluorescent Filter Technique ◽  
Triton X

The results from a shortened procedure for the direct epifluorescent filter technique (DEFT) determination of viable bacterial populations in raw milk were compared to standard plate counts. Shortening the prefiltration trypsin-Triton X-100 incubation period from 10 to 3 min enabled the completion of the analysis within 20 min. The short DEFT method results had a correlation coefficient (r) of 0.81 with plate counts. With respect to precision, the average difference between values of duplicate plate count analyses was 0.16 log units; that of the short DEFT was 0.14 log units. The slopes of the regressions equations were less than 1, indicating that a direct correlation is not achieved. Short DEFT values were 0.17 log units higher than those of plate counts on milk samples containing less than 10,000 CFU/ml. For milk samples containing counts over 10,000 CFU/ml, short DEFT values averaged only 0.05 log units above plate count readings. Daily preparation of the stain appears unnecessary since acridine orange solutions stored for up to 2 days at 4°C did not produce results significantly (P > 0.05) different from those obtained with fresh solutions. The short DEFT method has potential for the assessment of the bacteriological quality of raw milk in tanker deliveries.

Quantitation of Microorganisms in Raw Minced Meat Using the Direct Epifluorescent Filter Technique: NMKL Collaborative Study

1992 ◽  
Vol 75 (3) ◽  
pp. 465-473 ◽  
Author(s):  
Flemming Boisen ◽  
Niels Skovgaard ◽  
Steen Ewald ◽  
Gunnar Olsson ◽  
Gun Wirtanen
Keyword(s):  
Quality Control ◽  
Standard Deviation ◽  
Collaborative Study ◽  
Plate Count ◽  
Special Model ◽  
Filter Technique ◽  
Orange Fluorescence ◽  
Repeatability Standard Deviation ◽  
Direct Epifluorescent Filter Technique ◽  
Minced Meat

Abstract Fourteen Nordic laboratories participated In an Interlaboratory study of microorganisms In raw minced meat. After 2 preliminary collaborative evaluations of 20 and 6 prepared direct epifluorescent filter technique (DEFT) slides, the equipment and the counting technique were adjusted and standardized. In the following third and final trial, the laboratories examined 10 samples in duplicate. A special model was developed for homogenlzatlon, preservation, and transport of raw minced meat within 24 h. Test microorganisms were those present naturally In the meat. The participating laboratories received Identical samples in duplicate at 10 counting levels. The results Indicated a coefficient of variation of 15% by Interlaboratory counting of 26 prepared DEFT slides. By examining samples of raw minced meat for microorganisms showing any degree of orange fluorescence, the repeatability and the reproducibility were 0.41 and 0.78, respectively. The repeatability standard deviation (sr) was0.14, and the reproducibility standard deviation (SR) was 0.27. The study demonstrated that DEFT Is a dependable method for quantitation of microorganisms in raw minced meat. Precision of DEFT was in agreement with Nordic Committee on Food Analysis standard deviation values used In the Nordic countries for plate-count quality control.

Rapid Estimation of Microbial Numbers on Meat and Poultry by the Direct Epifluorescent Filter Technique

1987 ◽  
Vol 50 (8) ◽  
pp. 652-657 ◽  
Author(s):  
B. G. SHAW ◽  
C. D. HARDING ◽  
W. H. HUDSON ◽  
L. FARR
Keyword(s):  
Red Meat ◽  
Particulate Material ◽  
Plate Count ◽  
Skin Scraping ◽  
Rapid Estimation ◽  
Filter Technique ◽  
Plate Counts ◽  
Direct Epifluorescent Filter Technique ◽  
Raw Poultry ◽  
Microbial Numbers

The direct epifluorescent filter technique (DEFT) for rapid estimation of microbial numbers was evaluated by comparison with the plate count on a variety of uncooked red meat and poultry samples. Good agreement [correlation coefficient (r) = 0.95–0.96] was obtained from samples with plate counts of 5 × 103/g or /cm2 and above from red meat carcasses (surface swabbed), aerobic or vacuum packed chill-stored joints (surface sampled - stomachered) and frozen beef (thawed stomachered). For stored and unstored raw poultry sampled by skin scraping or stomachering of muscle and skin good overall correlation (r = 0.88–0.89) was obtained between the DEFT count and the plate count in the ranges 1.1 × 103 to 1.3 × 107/cm2 (skin scraping) and 1 × 104 to 9.5 × 106/g (muscle and skin) even though the DEFT always overestimated counts on samples on which no growth had occurred (plate count <7×104/cm2 or <1×105/g). However, good linearity between DEFT and plate counts allowed use of the regression equation to obtain a good estimate of the plate count on these samples. The DEFT was unsuitable for application to poultry neck skin sampled by shaking because particulate material interfered with counting. This was also a problem with Mechanically Recovered Meat although the DEFT gave a fair estimate (r = 0.72) of the plate count on certain types (beef and veal) of this product. The DEFT was capable of providing counts within 35 to 45 min and its applicability to the rapid estimation of bacterial numbers in meat and poultry is discussed.

Study of the Microbial Ecology of Wild and Aquacultured Tunisian Fresh Fish

2011 ◽  
Vol 74 (10) ◽  
pp. 1762-1768 ◽  
Author(s):  
MOUNA BOULARES ◽  
LOBNA MEJRI ◽  
MNASSER HASSOUNA
Keyword(s):  
Aeromonas Hydrophila ◽  
Microbiological Quality ◽  
Common Species ◽  
Microbial Populations ◽  
Plate Count ◽  
Gram Negative Bacteria ◽  
Fresh Fish ◽  
Psychrotrophic Bacteria ◽  
Aerobic Plate Count

Eighty samples of fresh fish were collected in Tunisia and analyzed for microbial load. Quality and hygienic safety of the meat and intestines of wild and aquacultured fresh fish were determined. The mesophilic aerobic plate count and populations of psychrotrophic lactic acid bacteria (LAB) and other psychrotrophic bacteria ranged from 5.67 to 7.29, 4.51 to 6, and 5.07 to 6.21 log CFU/g, respectively. For all microbiological determinations, bacterial counts were lower in meat than in the intestines of fresh fish. For all samples lower microbial populations were found in most of the wild fish than in the aquacultured fish. No isolates of the pathogenic genera Salmonella and Listeria were detected in any sample. Among the 160 strains of biopreservative psychrotrophic LAB and the 150 strains of spoilage psychrotrophic gram-negative bacteria identified by biochemical and molecular methods, Lactobacillus (six species) and Pseudomonas (six species) predominated. Lactococcus, Leuconostoc, Carnobacterium (C. piscicola and C. divergens), Aeromonas, and Photobacterium were the most common genera, and Lactococcus lactis, Lactobacillus plantarum, Pseudomonas fluorescens, and Aeromonas hydrophila were the most common species. These findings indicate that the microbiological quality of fresh fish in Tunisia can be preserved by controlling pathogenic and psychrotrophic bacteria.

Microbial Quality of Hoummos (Chickpea Dip) Commercially Produced in Jordan

1994 ◽  
Vol 57 (5) ◽  
pp. 431-435 ◽  
Author(s):  
MOHAMMED I. YAMANI ◽  
BASIM A. AL-DABABSEH
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Low Ph ◽  
Plate Count ◽  
Microbial Quality ◽  
Aerobic Plate Count ◽  
And Staphylococcus Aureus ◽  
Reference Samples ◽  
Hygienic Conditions

Sixty samples of fresh hoummos (chickpea dip) from 15 restaurants were examined in winter and summer to find out numbers and types of microorganisms present. Five reference samples, produced by the investigators under hygienic conditions, were examined for comparison. The microbial load of commercial hoummos was high, and spherical lactic acid bacteria (LAB) belonging to Lactococcus, Enterococcus and Leuconostoc were the predominant microorganisms. The means of the aerobic plate count (APC) and the counts of LAB and coliforms (1.9 × 108, 1.6 × 108 and 2.9 × 105/g, respectively) in summer samples were significantly higher (p < 0.05) than the averages of the same counts in winter samples (2.7 × 107, 1.6 × 107 and 2.2 × 103/g). The average summer and winter yeast counts were 4.2 × 104 and 1.5 × 104g, respectively. In reference samples of hoummos, APC and LAB counts were < 103/g, while the coliform and yeast counts were < 10/g and 102/g, respectively, indicating lack of hygienic practices during the production of commercial hoummos. Salmonella was not detected in any sample, and Escherichia coli and Staphylococcus aureus counts of all samples were < 10/g. The relatively low pH of hoummos (the average pH of all samples was 5.1) and the rapid growth of LAB, possibly accompanied by production of inhibitory substances, may explain the predominance of these bacteria, and could have contributed to the absence of the pathogens examined.

Survey of the Bacterial Populations of Bologna Products1,2

1978 ◽  
Vol 41 (9) ◽  
pp. 692-695 ◽  
Author(s):  
JOHN T. FRUIN ◽  
JAMES F. FOSTER ◽  
JAMES L. FOWLER
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Foodborne Pathogens ◽  
High Volume ◽  
Plate Count ◽  
Retail Market ◽  
Bacterial Populations ◽  
Retail Markets ◽  
Aerobic Plate Count

Bologna products most frequently are stored and consumed as refrigerated products. Thus bacteria that survive processing or those that contaminate the product subsequent to processing are not destroyed. Ten types of presliced, vacuum-packaged bologna products were purchased from a high-volume retail market and analyzed for total aerobic plate count (APC) and common foodborne pathogens. No Salmonella were isolated. Less than 1% of the 419 samples analyzed contained either Clostridium perfringens or Escherichia coli, Staphylococcus aureus was isolated from 4% of the samples, but only one sample contained more than 1000/g. Just over 5% of the samples contained coliform organisms. The manufacturer appeared to play an important role in bacterial quality of the finished items. An APC < 5 × 106/g is a realistic criterion for bologna products at the time of delivery to retail markets.

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