Pre-enrichment Broths for Recovery of Salmonella from Milk Chocolate and Edible Casein: Collaborative Study

1981 ◽  
Vol 64 (4) ◽  
pp. 893-898
Author(s):  
Paul L Poelma ◽  
Wallace H Andrews ◽  
Clyde R Wilson ◽  
◽  
C M Coles ◽  
...  

Abstract A collaborative study was conducted to compare the relative efficiency of nonfat dry milk with brilliant green dye (NFDM-BG) and buffered peptone water (BPVV) as pre-enrichment broths for recovery of Salmonella from milk chocolate. Lactose broth and modified lactose broth with added 1% NaHCO3 and brilliant green dye were compared as pre-enrichment broths for recovery of Salmonella from edible casein. Two sets of 8 samples each of milk chocolate, containing initial levels of Salmonella ranging from <0.03 to 43 organisms/g, were examined by 13 collaborators. Of 104 determinations, 102 (98.1%) and 100(96.2%) using NFDM-BG and BPW, respectively, were in agreement with sample results of the control laboratory. Two sets of 7 samples each of edible casein, containing initial levels of Salmonella ranging from <0.03 to 93 organisms/g, were also examined by the 13 collaborators. Of 91 determinations, 87 (95.6%) and 88 (96.7%) using lactose broth and modified lactose broth, respectively, were in agreement with sample results of the control laboratory. For recovery of Salmonella, therefore, NFDM-BG pre-enrichment is recommended for milk chocolate, and lactose broth is recommended for casein. The proposed revision of official final action method 46.054-46.067 has been adopted official first action

1984 ◽  
Vol 67 (4) ◽  
pp. 807-810
Author(s):  
Paul L Poelma ◽  
Wallace H Andrews ◽  
Clyde R Wilson ◽  
◽  
B Bennett ◽  
...  

Abstract A collaborative study was conducted to compare the relative efficiency of the AOAC rapid rehydration method with the reduced rehydration soak method for the recovery of Salmonella species from nonfat dry milk (NFDM). In the AOAC method, a 25 g sample of NFDM is rapidly rehydrated at a 1:9 sample/water ratio and mixed by swirling. After 60 min, the flask contents are adjusted to a pH of 6.8, and 0.45 mL of 1% aqueous brilliant green dye solution is added. The flasks are then incubated at 35°C. In the soak method, a 25 g sample of NFDM is gently added to the sterile brilliant green (BG) water at a 1:9 sample/ BG water ratio and allowed to soak undisturbed for 60 min at room temperature before incubation. Twelve collaborators analyzed 3 shipments of samples with the following results for the AOAC and soak methods: shipment 1—31 and 46 positive samples, respectively, with a 48% increase in detection by the soak method; shipment 3-45 and 66 positive samples, respectively, with a 47% increase in detection by the soak method; shipment 2—no significant difference in recovery of Salmonella species by the 2 methods. It is recommended that the official final action method for the detection of Salmonella species, 46.054- 46.067, be revised to use the soak method for the analysis of nonfat dry milk.


1997 ◽  
Vol 80 (3) ◽  
pp. 491-504 ◽  
Author(s):  
Michael S Curiale ◽  
Vidhya Gangar ◽  
Carol Gravens ◽  
J R Agin ◽  
A Bound ◽  
...  

Abstract The VIDAS SLM method for detection of Salmonella was compared with the Bacteriological Analytical Manual (BAM)/AOAC culture method in a collaborative study. Twenty laboratories participated in the evaluation. Each laboratory tested one or more of 6 test products: milk chocolate, nonfat dry milk, dried whole egg, soy flour, ground black pepper, and ground raw turkey. No significant differences (P< 0.05) were observed between the 2 methods. The 2 methods were in agreement for 99% of 1544 samples analyzed. Of the 20 samples out of agreement, 8 were VIDAS SLM positive and BAM/AOAC negative, and 12 were VIDAS SLM negative and BAM/AOAC positive. The VIDAS SLM method for detection of Salmonella in foods has been adopted first action by AOAC INTERNATIONAL.


2002 ◽  
Vol 85 (3) ◽  
pp. 609-625 ◽  
Author(s):  
Wendy A Lepper ◽  
Ann M Schultz ◽  
Michael S Curiale ◽  
Ronald L Johnson ◽  
J Agin ◽  
...  

Abstract The VIDAS Immuno-concentration Salmonella (ICS)/VIDAS Salmonella (SLM) immunoassay method for the detection of Salmonella was compared to the Bacteriological Analytical Manual (BAM)/AOAC culture method in a collaborative study. Thirty-two laboratories participated in the evaluation. Each laboratory tested one or more of the 6 test products: milk chocolate, nonfat dry milk, dried whole egg, soy flour, ground black pepper, and ground raw turkey. The 2 methods were in agreement for 1266 of the 1440 samples. Of the 174 samples not in agreement, 69 were VIDAS ICS/SLM-positive and BAM/AOAC-negative and 105 were VIDAS ICS/SLM-negative and BAM/AOAC-positive.


2002 ◽  
Vol 85 (3) ◽  
pp. 593-608 ◽  
Author(s):  
Wendy A Lepper ◽  
Ann M Schultz ◽  
Michael S Curiale ◽  
Ronald L Johnson ◽  
J Agin ◽  
...  

Abstract The VIDAS Immuno-concentration Salmonella (ICS) plus selective plate method (Hektoen enteric, xylose lysine desoxycholate, bismuth sulfite) method for the detection of Salmonella was compared to the Bacteriological Analytical Manual (BAM)/AOAC culture method in a collaborative study. Thirty-two laboratories participated in the evaluation. Each laboratory tested one or more of the 6 test products: milk chocolate, nonfat dry milk, dried whole egg, soy flour, ground black pepper, and ground raw turkey. The 2 methods were in agreement for 1297 of the 1455 samples. Of the 158 samples not in agreement, 82 were VIDAS ICS plus selective plate-positive and BAM/AOAC-negative, and 76 were VIDAS ICS plus selective plate-negative and BAM/AOAC-positive.


1969 ◽  
Vol 52 (3) ◽  
pp. 455-458
Author(s):  
P L Poelma ◽  
C R Wilson ◽  
A Romero ◽  
A Padron

Abstract A method for the detection and identification of Salmonella from dry milk was subjected to collaborative study. A 100 g sample is reconstituted in 1 L distilled water with 2 ml 1% aqueous brilliant green dye, incubated, subcultured in selenite cystine broth and tetrathionate broth, incubated, and streaked on selective plates of brilliant green agar, Salmonella-Shigella agar, and bismuth sulfite agar. After incubation, suspicious colonies can be further identified by biochemical and serological tests. Samples of nonfat dry milk and dry whole milk, some inoculated with Salmonella binza, Salmonella tvorthington, and Citrobacter, were examined by 30 collaborators. Results from 23 of 28 collaborators were in agreement; the method will detect and identify Salmonella from positive nonfat dry milk and dry whole milk. The method is recommended for adoption as official first action.


2003 ◽  
Vol 86 (4) ◽  
pp. 714-718 ◽  
Author(s):  
Thomas S Hammack ◽  
R Miguel Amaguaña ◽  
Mildred L Johnson ◽  
Wallace H Andrews

Abstract The relative efficiencies of 2 Bacteriological Analytical Manual (BAM) pre-enrichments, lactose broth (LAC) and brilliant green water (BGW), were compared with Universal Pre-enrichment (UP) broth for the recovery of individual Salmonella serovars from instant nonfat dry milk (NFDM), dry whole milk (DWM), lactic casein (LC), and liquid whole milk (LWM). BGW was compared with UP broth for the analysis of NFDM and DWM but not with the other 2 matrixes. LAC was compared with UP broth for the analysis of LC and LWM. UP broth was made both from a commercial dehydrated preparation (UPC) and from individual ingredients (UPI). Bulk quantities of the selected dairy foods were inoculated with Salmonella serovars at levels intended to produce fractionally positive results, where at least half of the test portions analyzed, with one of the methods being evaluated, would be shown to be Salmonella-positive. For NFDM, in 6 of 9 experiments, with 2 different Salmonella serovars, BGW was significantly more productive than either UPI or UPC broth (p < 0.05). Salmonella was recovered from 118 of 180 test portions with BGW, from 25 of 180 test portions with UPC, and from 14 of 180 test portions with UPI. For DWM, in 2 of 4 experiments, with 2 different Salmonella serovars, BGW was significantly more productive than either UPI or UPC broth (p < 0.05). Salmonella was recovered from 67 of 80 test portions with BGW, from 36 of 80 test portions with UPC, and from 37 of 80 test portions with UPI. For LWM, in 9 of 9 experiments, with 3 different Salmonella serovars, there were no significant differences among the broths. Salmonella was recovered from 120 of 180 test portions with LAC, from 135 of 180 test portions with UPC, and from 129 of 180 test portions with UPI. For LC, in 5 of 7 experiments, with 2 different Salmonella serovars, both UPI and UPC broth were significantly more productive than LAC (p < 0.05). Salmonella was recovered from 42 of 140 test portions with LAC, from 114 of 140 test portions with UPC, and from 114 of 140 test portions with UPI. In addition, overall results showed that UPC and UPI broths were equivalent for the recovery of Salmonella from the foods tested, without regard to their performance in comparison with either LAC or BGW.


1984 ◽  
Vol 67 (2) ◽  
pp. 232-236
Author(s):  
Nrisinha P Sen ◽  
Stephen Seaman ◽  
K Karpinsky ◽  
◽  
M Castegnaro ◽  
...  

Abstract Ten laboratories participated in a collaborative study of a method for the determination of JV-nitrosodimethylamine (NDMA) in nonfat dry milk. NDMA is eluted with dichloromethane from a mixture of Celite, acidic sulfamic acid, and nonfat dry milk (all packed in a chromatography column), concentrated in a Kuderna-Danish concentrator, and finally analyzed by a GC-thermal energy analyzer technique. Ten samples were studied: 6 were naturally contaminated (NDMA levels 0.38- 3.56 ppb) and 4 were spiked with known levels (0.96 and 3.2 ppb) of NDMA. The coefficients of variation (CV) of the complete data for the naturally contaminated samples (excluding the 2 samples containing the lowest levels) were 8.5% and 22.5% for repeatability and reproducibility, respectively. The corresponding CVs for the spiked samples were 14.4% and 20.4%, respectively. The percent recoveries of the added NDMA in the spiked samples (at the 2 levels indicated above) were 101.6 ± 3.2 (omitting 1 outlier) and 95 ∓ 2.1, respectively. The method has been adopted official first action.


1981 ◽  
Vol 64 (4) ◽  
pp. 899-928
Author(s):  
Wallace H Andrews ◽  
Paul L Poelma ◽  
Clyde R Wilson ◽  
◽  
C Abeyta ◽  
...  

Abstract The relative efficiency of brilliant green (BG), bismuth sulfite (BS), Salmonella-Shigella (SS), xylose lysine desoxycholate (XLD), and Hektoen enteric (HE) agars for the recovery of Salmonella from 5 foods was collaboratively studied in 11 laboratories. The analytical efficiency of various paired combinations of the 5 agars was statistically compared according to 3 parameters: (1) productivity or recovery of Salmonella, (2) rate of enumeration of cultures that were false positive for Salmonella, and (3) rate of enumeration of false-negative reactions. In descending order of productivity, the sequential rankingwasBS, XLD, HE, BG, and SS agars. In ascending order, the rates of false-positive reactions based on a statistical analysis of paired agar combinations was HE, BS, BG and XLD (tie), and SS agars. Analogously, in ascending order, the sequence of false-negative reaction rates was BS, XLD, HE, BG, and SS agars. The combination of BS, XLD, and HE agars is more efficient for recovery of Salmonella from foods than is the present official combination of BG, BS, and SS agars. The revision of official final action method 46.054 to replace the combination of BG, BS, and SS agars with a combination of BS, XLD, and HE agars has been adopted official first action.


1983 ◽  
Vol 66 (4) ◽  
pp. 897-904
Author(s):  
Phyllis Entis ◽  
◽  
B W Ciebin ◽  
V Gipson ◽  
M Grahn ◽  
...  

Abstract A collaborative study was conducted in 14 laboratories to evaluate the performance of the hydrophobic grid membrane filter method against the official final action method, 46.016, for enumeration of colif orms in foods. Twelve artificially contaminated samples of nonfat dry milk and canned custard were analyzed by each laboratory. The random errors (Sr2) associated with the hydrophobic grid membrane filter method were significantly lower than those of the official method, and the counts obtained by the new method fell within the 95% confidence interval of the reference method. The colif orm counts obtained by tiie hydrophobic grid membrane filter method did not differ significantly from those obtained by the reference method as measured by a 3-way analysis of variance. The new method has been adopted official first action.


1985 ◽  
Vol 68 (3) ◽  
pp. 555-564
Author(s):  
Phyllis Entis

Abstract A collaborative study was carried out in 36 laboratories to validate a hydrophobic grid membrane filter method for rapid (2-3 days) Salmonella detection by comparing its performance against the AOAC/ BAM reference method. Six products were included in the study: semisweet chocolate, raw ground poultry meat, ground black pepper, cheese powder, egg powder, and nonfat dry milk. With the exception of the naturally contaminated poultry, all products were inoculated in advance with low concentrations of a variety of Salmonella serotypes. The hydrophobic grid membrane filter method detected the following numbers of positive samples (results of the AOAC/BAM reference method are shown in parentheses): chocolate, 67(68); raw ground poultry, 133(131); ground black pepper, 57(56); cheese powder, 81(80); egg powder, 51(45); and nonfat dry milk, 68(72). The 2 methods did not differ significantly at the 95% confidence level in any of the 6 foods. The hydrophobic grid membrane filter method has been adopted official first action for detection of Salmonella in selected foods.


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