scholarly journals Validation of RAPID' Staph for Enumeration of Staphylococcus aureus in Foods

2007 ◽  
Vol 90 (2) ◽  
pp. 414-426 ◽  
Author(s):  
Wendy F Lauer ◽  
Sandrine M T Gary ◽  
Asmita Patel

Abstract RAPID' Staph (Bio-Rad Laboratories, Hercules, CA) is a medium for differentiation and enumeration of coagulase-positive Staphylococcus aureus in food. RAPID'Staph medium is based on a Baird Parker formula optimized for the detection and enumeration of S. aureus in 24 h. The principle of the medium relies on the capacity of S. aureus to reduce tellurite (production of black colonies) and to provoke proteolysis of egg yolk (production of clear halo around the colony). Four foods (pasteurized whole milk, custard pie, processed ham, and smoked salmon) were selected to compare the performance of RAPID' Staph agar to AOAC Official Method 975.55. Method comparison studies demonstrated excellent agreement between the methods. Inclusivity and exclusivity rates of the medium were 100%. RAPID' Staph agar performed as expected when minor procedural variations were introduced, validating the ruggedness of the method. There was no difference in performance between the dehydrated and ready-to-use formulations of the media.

2003 ◽  
Vol 86 (5) ◽  
pp. 947-953 ◽  
Author(s):  
Wendy A McMahon ◽  
Victoria A Aleo ◽  
Ann M Schultz ◽  
Barbara L Horter ◽  
Kathryn G Lindberg ◽  
...  

Abstract The 3M™ Petrifilm™ Staph Express Count plate method was compared with AOAC Official Method 975.55 for the enumeration of Staphylococcus aureus in selected foods. Four foods—cooked, diced chicken; cured ham; smoked salmon; and pepperoni—were analyzed for S. aureus by 12 collaborating laboratories. For each food tested, the collaborators received 8 blind test samples consisting of a control sample, a low inoculation level, a medium inoculation level, and a medium inoculation level with background flora, each in duplicate. The mean log10 counts for the methods were comparable for all 4 foods. The repeatability and reproducibility variances of the 24 h Petrifilm Staph Express Count plate method were similar to those of the 72 h standard method.


2009 ◽  
Vol 92 (5) ◽  
pp. 1432-1453 ◽  
Author(s):  
Vicki Ritter ◽  
Susan Kircher ◽  
Krista Sturm ◽  
Patty Warns ◽  
Nancy Dick

Abstract BBL CHROMagar Staph aureus (CSA) medium was evaluated internally and externally for the isolation and enumeration of Staphylococcus aureus in cooked roast beef, smoked salmon, and shell eggs. All food matrixes were processed according to the AOAC Official Method 975.55 and ISO 6888-1:1999. Bacterial counts of S. aureus were compared on CSA to the reference media, Baird-Parker, at low, medium, and high contamination levels. Colony counts were converted to log10 for statistical analysis. Based on the paired t-test and one-way analysis of variance, no statistical difference was noted with the CSA method compared to the AOAC Official Method for the recovery of S. aureus for all food types and contamination levels. Compared to the ISO reference method, no statistical difference was found with the CSA method for any food type or contamination level, with the exception of low-level smoked salmon. A statistical difference was seen in the internal testing with the low-level contaminated smoked salmon where CSA recovered more colonies. The external testing showed no statistical difference with smoked salmon at the low level. The correlation coefficients ranged from 92.6 to 99.4, demonstrating good correlation for overall levels in all food types and methods. The sensitivity and specificity of the CSA method using known isolates was 100. The results of this study demonstrate that CSA is an effective medium for the isolation, enumeration, and presumptive identification of S. aureus in cooked roast beef, smoked salmon, and shell eggs in 24 h using ISO and AOAC official methods.


1970 ◽  
Vol 53 (1) ◽  
pp. 3-6
Author(s):  
R. Bruce Klemm ◽  
Mary E. Ambrose Klemm

Abstract The AOAC official method, 24.029–24.035, for the determination of fluorine in foods was modified slightly to o btain quantitative recoveries of fluorine from samples of fish protein concentrate (FPC). The most important alterations include the use of steam distillation, the addition of finely ground silica sand in the distillation, a decrease in the distillation temperature, and the utilization of direct titration. Recoveries of fluoride added to FPC before ashing, using this modified method, averaged 96.0 ± 3.0%. Our results are in agreement with those of several other analysts who used a variety of methods.


2014 ◽  
Vol 19 (1) ◽  
pp. 27
Author(s):  
Haryoto Kusnoputranto ◽  
Setyo S Moersidik ◽  
Djarot S Wisnubroto ◽  
Murdahayu Makmur

Ledakan mikroalga sering dilaporkan terjadi di Teluk Jakarta, dimana di lokasi tersebut juga terdapat kegiatan budidaya kerang hijau (Perna viridis). Terkait dengan hal tersebut maka dilakukan studi akumulasi dan depurasi toksin PSP (Paralytic Shellfish Poisoning) pada kerang hijau. Studi akumulasi dilakukan di bagan kerang hijau perairan Cilincing Jakarta Utara, dengan memisahkan kerang hijau yang berukuran sama dan ditempatkan kembali ke bagan. Sampling dilakukan setiap minggu selama 2 bulan dan diukur juga kelimpahan fitoplankton, pH, suhu dan salinitas perairan. Depurasi dilakukan di Unit Depurasi Kekerangan KKP Panimbang Banten, yang dilakukan selama 24 jam. Pencuplikan  sampel dilakukan setiap jam pada 4 jam pertama dan setiap 2 dan 3 jam pada waktu berikutnya. Penentuan konsentrasi toksin PSP dilakukan dengan menggunakan HPLC detektor fluoresensi. Prosedur preparasi, ekstraksi dan pengukuran konsentrasi toksin mengikuti Manual AOAC Official Method 2005.06 untuk toksin PSP dalam kekerangan. Akumulasi toksin PSP oleh kerang hijau di perairan Cilincing pada bulan Januari–Pebruari 2011 berkisar antara 4,11–11,96 µg STX eq. per 100 g dan tidak mempunyai korelasi dengan kelimpahan Dinoflagelata di perairan. Hal ini disebabkan uji akumulasi tidak dilakukan pada saat blooming mikroalga. Uji depurasi selama 24 jam mengeliminasi toksin PSP sebesar 60%, sehingga bisa diajukan sebagai sistem pemutus rantai toksin dari mikroalga ke manusia. Kata kunci: akumulasi, depurasi, PSP toksin, kerang hijau, Cilincing Microalgae blooms have been frequently reported in the Jakarta Bay, which is also the location of green mussel (Perna viridis) aquaculture. Accumulation and depuration of Paralytic Shellfish Poisoning (PSP) toxin in the green mussels were investigated in the field, where the toxin accumulation studies conducted in the mussel farming at Cilincing, North Jakarta. Accumulation test carried out by placing back the selected green mussel (equal size) into the mussel farming. Every week for 2 months, the green mussel were collected from mussel farming and transported to the laboratory. The fitoplankton abundance also was checked including pH, Suhue and salinitiy paramaters. Toxin depuration was conducted at Clams Sanitation Unit at Panimbang Banten. The depuration studies were conducted for 24 hours with sampling every hour in the first 4 hours and every 3 and 2 hours until the 24th hour. Preparation, extraction and toxin concentration measurements performed by following the Manual AOAC Official Method 2005.06 for PSP toxin in oyster. This research concluded that the accumulation of PSP toxin by green mussel, Perna viridis in the mussel farming at Cilincing, North Jakarta in ranged between 4,11–11,96 µg STX eq. per 100 g during January–February 2011. No correlation between PSP toxin concentration in the green mussel, Perna viridis with abundance of the PSP toxin sources phytoplankton, because the study wasnt done when microalgae blooming. The depuration processes was eliminate 60% the PSP toxins for 24 hours depuration processing. It can be proposes as a banded system the PSP toxin from algae to human being. Keywords: accumulation, depuration, PSP toxin, green mussel, Cilincing


1970 ◽  
Vol 53 (1) ◽  
pp. 1-3 ◽  
Author(s):  
Donald L Andersen

Abstract A new GLC method for the determination of allyl isothiocyanate in mustard seed was compared to a method of the Midwest Research Institute and to a combination of the AOAC official method and the proposed method. Twelve collaborators compared the AOAC method and the GLC method, using whole mustard seeds. Each collaborator assayed three seed portions by both methods. The range, standard deviation, and coefficient of variation are less for each seed portion by the proposed than by the official method. The average recovery value of allyl isothiocyanate in the prepared standard solutions is lower, using the proposed GLC procedure, but seed assay values are significantly and consistently higher for each seed portion when compared with the results for the AOAC method. Reports from the collaborators also indicate that the proposed method is rugged, as the GLC column preparation was subjected to many changes. It is recommended that the GLC method be adopted as official first action.


1997 ◽  
Vol 80 (6) ◽  
pp. 1235-1271 ◽  
Author(s):  
Jane E Fox Dobson ◽  
Foster D McClure ◽  
Alvin P Rainosek ◽  
K Dashiell ◽  
J Fox Dobson ◽  
...  

Abstract An intralaboratory1collaborative study evaluated a modified version of AOAC Official Method 971.13 for determining the fish flesh content (FFC) in frozen coated fish products by comparing it with the on-line method. Eleven collaborators analyzed 36 products (a total of 6336 test samples). Each product targeted one of 4 percent fish flesh (PFF) levels (35,50,65, and 80). Products were manufactured from one of 3 raw materials (fillet blocks, minced blocks, and natural fillets) and processed in one of 4 forms (sticks, portions, formed portions, and fillets) and one of 4 styles (raw breaded, batter-dipped, precooked, and fully cooked). Each “official” test sample was tracked through the processing system and weighed (1) before battering and/or breading and, depending on product style, before frying; and (2) after battering and/or breading and, depending on product style, after frying; so that it served as its own control.


1996 ◽  
Vol 79 (4) ◽  
pp. 907-916 ◽  
Author(s):  
Joanna M Lynch ◽  
David M Barbano ◽  
J Richard Fleming

Abstract A modified Mojonnier ether extraction method for determination of the fat content of cream was developed based on the method for milk (AOAC Official Method 989.05). The cream Babcock method (AOAC Official Method 920.111 B-C) was modified to harmonize with the milk Babcock method (AOAC Official Method 989.04) and to clarify procedural details. Using the AOAC collaborative study format, 10 laboratories tested 9 pairs of blind duplicate heat-treated cream samples with a fat range of 30-45% using both methods. The statistical performance (invalid and outlier data removed) was as follows: mean % fat = 37.932, sr = 0.125, sR = 0.151, RSDr = 0.330, RSDR = 0.398, r = 0.354, and R = 0.427 for the ether extraction method. For the Babcock method, mean % fat = 38.209, sr = 0.209, SR = 0.272, RSDr = 0.548, RSDR = 0.712, r = 0.592, and R = 0.769. Average test results for fat from the Babcock method were 0.277% (absolute fat) greater than for the Mojonnier ether extraction method. The difference between methods, as a percentage of the average fat content of the samples, was 0.73%. This agrees with differences observed between the 2 methods for milk when 10 to 17 laboratories tested 7 milk samples in blind duplicate at bimonthly intervals over a 4-year period (average difference 0.029% fat, 0.78% as a percentage of average fat content). The Mojonnier ether extraction and Babcock methods for fat in cream have been adopted by AOAC INTERNATIONAL. The new Babcock method replaced the AOAC Official Method 920.111 B-C.


2008 ◽  
Vol 91 (2) ◽  
pp. 365-369 ◽  
Author(s):  
Philip T Feldsine ◽  
David E Kerr ◽  
George S Shen ◽  
Andrew H Lienau

Abstract The Visual Immunoprecipitate (VIP®) for the Detection of Listeria in Foods and Environmental Surfaces, AOAC Official Method 997.03, has been modified to use a simplified housing for the device. A methods comparison study was conducted to demonstrate the equivalence of this modification to the reference culture methods. Two food matrixes and one environmental surface were analyzed. In total, valid results were obtained from 145 samples and controls. Results showed that the modified VIP for Listeria spp. is equivalent to the reference culture methods for the detection of Listeria.


1999 ◽  
Vol 82 (5) ◽  
pp. 1146-1155 ◽  
Author(s):  
Jonathan W DeVries ◽  
Lori Kjos ◽  
Linda Groff ◽  
Martin Bob ◽  
Cernohous Kristi ◽  
...  

Abstract Quantitation of fat in foods has been performed successfully with AOAC Official Method 996.06. A number of situations have been encountered that render the method note, “Note: For any unknown or uncalibrated peaks, use the nearest calibrated fatty acid response factors and conversion factors,” inaccurate. Identification of extraneous compounds and availability of additional standard fatty acid methyl esters combined with mass spectral data lead to the recommendation of modifications in Official Method 996.06. The stepwise performance of the method remains unchanged.


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