Enumeration and Confirmation of Bacillus cereus in Foods: Collaborative Study

Abstract

A collaborative study was conducted in 15 laboratories to evaluate 2 different techniques for enumerating Bacillus cereus in foods. A direct plating technique using mannitol-egg yolk-polymyxin agar and a most probable number (MPN) technique using trypticase-soy-polymyxin broth were compared for the enumeration of high and low populations of B. cereus in mashed potatoes. The collaborative results showed that the overall mean recovery obtained with the low population level was essentially the same by both techniques. However, the overall mean recovery was significantly higher by the direct plating technique at the high population level. A statistical evaluation of the data also showed that the direct plating technique had better repeatability and reproducibility than did the MFN technique at both the high and low population levels. These results suggest that the MPN technique is suitable for examining foods containing low populations of B. cereus, but that the direct plating technique is preferable for foods that contain a high population of this organism. The confirmatory technique used in the proposed method is reliable for presumptive identification of isolates as B. cereus. The method has been adopted as official first action.

ACID PH PRODUCED BY LACTIC ACID BACTERIA PREVENT THE GROWTH OF BACILLUS CEREUS IN BOZA, A TRADITIONAL FERMENTED TURKISH BEVERAGE

“…During fermentation, 10 mL of boza samples were taken under aseptic conditions for microbiological counts at 0, 4, 8, 12, 24, 30, 34, 48 and 72 h of incubation and then transferred into 90 mL (0.1%) peptone water. From appropriate 10‐fold dilutions, spread plate counts were made using the following media and incubation conditions: Mannitol egg yolk polymixin B (MYP) agar (Lancette and Harmon 1980) for B. cereus , 30C, 24–48 h incubation (Wong et al. 1988); Man, Rogosa and Sharpe (MRS) (Oxoxid CM361) agar for LAB, 30C, 48–72 h incubation; and dichloran rose bengal chloramphenicol (Oxoid CM727) agar for yeasts, 30C, 24–48 h incubation (Zorba et al.…”

Prevalence, characterization and growth of Bacillus cereus in commercial cooked chilled foods containing vegetables

“…J‐broth (JB) had the same composition as JA but did not contain agar. The selective media for Bacillus cereus were Polymyxin‐Eggyolk‐Mannitol‐Bromothymol Blue‐agar (PEMBA) (Oxoid) and Mannitol‐Eggyolk‐Phenol red‐agar (MYP) prepared as described by Lancette and Harmon (1980). Soil extract agar contained JA mixed with the same volume of sterile soil infusion in deionized water and was prepared as described by Gordon et al .…”

INCIDENCE AND CHARACTERIZATION OF BACILLUS CEREUS IN MEAT AND MEAT PRODUCTS CONSUMED IN TURKEY

“…Serial dilutions were made and plated (0.1 mL) onto plate count agar (PCA, Oxoid, Basingstoke, Hants, U.K.) and incubated at 30C. The B. cereus count was determined by the surface plating method with mannitol egg yolk polymyxin (MYP) agar (Lancette and Harmon 1980), and the plates were incubated at 30C for 24 h for enumeration.…”

“…The first and best known type is characterized by abdominal pain and diarrhea, which occurs between 8 and 16 h after ingestion of the contaminated food. The second type of illness is characterized by nausea and vomiting, which occurs within 30 min to 5 h after eating contaminated food (Lancette and Harmon 1980). The Bacillus cereus enterotoxin (diarrheal type) (BCET)-reversed passive latex agglutination (RPLA) kit detects the diarrheal enterotoxin by RPLA, which was used successfully in many studies (Granum et al 1993;Gulam and Nur Hayati 1995;Fermanian et al 1996;Nout et al 1998;Valero et al 2002).…”