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Title: DETECTION OF BACILLUS CEREUS ON SELECTED RETAIL CHICKEN PRODUCTS.

Author
item Smith, Douglas
item Berrang, Mark
item Feldner, Peggy
item Phillips, Robert
item Meinersmann, Richard - Rick

Submitted to: Journal of Food Protection
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/6/2004
Publication Date: 8/1/2004
Citation: Smith, D.P., Berrang, M.E., Feldner, P.W., Phillips, R.W., Meinersmann, R.J. 2004. Detection of bacillus cereus on selected retail chicken products. Journal of Food Protection. 67(8):1770-1773.

Interpretive Summary: Bacillus cereus is a commonly occurring bacterial species found in soil, dust and grains. It has been associated with foodborne outbreaks, which have sometimes included meat or poultry products. It is a sporeformer, and spores can withstand adverse environmental conditions, including the high heat from cooking. For these reasons five different chicken meat products, obtained at retail stores, were evaluated for the presence of B. cereus. Products tested were: Breaded, fully cooked, frozen nuggets (NUGGETS); breaded, fully cooked, frozen tenders (TENDERS); fully-cooked, frozen, white meat fajita-style strips (STRIPS); raw, refrigerated boneless skinless marinated breast fillets (FILLETS); and, raw, refrigerated, cut-up, tray pack bone-in parts (PARTS), either split breasts or thighs. Four packages of each item were obtained on three different days (n=60). Samples from each item were tested for the presence of B. cereus, and isolates found were also tested for the presence of toxin encoding genes. B. cereus was detected in 27 of 60 total samples. By product the incidence levels were: NUGGETS, 11 of 12 positive; TENDERS, 8 of 12 positive; STRIPS, 6 of 12 positive; FILLETS, 0 of 12 positive; and, PARTS, 2 of 12 positive. Isolates were tested for presence of the toxin encoding genes bceT, nheABC, hblACD and cytK by polymerase chain reaction (PCR). Results indicate that Bacillus cereus organisms were present on four of the five retail poultry products tested in this study, with the highest rates reported for the three fully cooked items, especially the two breaded products. All strains isolated were found to contain the gene(s) for at least one of the toxins although none of the strains were found to contain the cytK gene.

Technical Abstract: Five chicken meat products, obtained at retail stores, were evaluated for the presence of Bacillus cereus. Products tested were: Breaded, fully cooked, frozen nuggets (NUGGETS); breaded, fully cooked, frozen tenders (TENDERS); fully-cooked, frozen, white meat fajita-style strips (STRIPS); raw, refrigerated boneless skinless marinated breast fillets (FILLETS); and, raw, refrigerated, cut-up, tray pack bone-in parts (PARTS), either split breasts or thighs. Four packages of each item were obtained on three different days (n=60). Frozen and refrigerated products were held overnight in their respective environments as appropriate, then packages were opened aseptically and a total of 25 g of tissue was excised from multiple pieces within a package. The 25 g samples were enriched in 225 ml trypticase soy-polymixin broth for 18-24 h at 30 C, then plated on MYP agar incubated 18-24 h at 30 C. Colonies characteristic of B. cereus were chosen and replated for isolation on MYP agar. Suspect colonies were confirmed as Bacillus spp. by gram reaction, hemolysis on blood agar, and a biochemical test strip. Isolates were further confirmed as B. cereus using Bacteriological Analytical Method procedures, including tests for motility, rhizoid growth, hemolysis, and protein toxin crystal production. B. cereus was detected in 27 of 60 total samples. By product the incidence levels were: NUGGETS, 11 of 12 positive; TENDERS, 8 of 12 positive; STRIPS, 6 of 12 positive; FILLETS, 0 of 12 positive; and, PARTS, 2 of 12 positive. Isolates were tested for presence of the toxin encoding genes bceT, nheABC, hblACD and cytK by PCR. Results indicate that Bacillus cereus organisms were present on four of the five retail poultry products tested in this study, with the highest rates reported for the three fully cooked items, especially the two breaded products. All strains isolated were found to contain the gene(s) for at least one of the toxins although none of the strains were found to contain the cytK gene.