A method to assess the bacterial content of refrigerated meat.
A new method has been developed to estimate the levels of gram-negative bacteria on refrigerated meat. The method is based on the aminopeptidase activity of these bacteria, which cleaves L-alanine-p-nitroanilide to yield p-nitroaniline, which is easily determined spectrophotometrically. This method allows the determination of levels around 10(6) to 10(7) CFU cm-2 in about 3 h. Because of the yellow color of p-nitroaniline, bacterial loads around 10(7) CFU cm-2 develop a color intense enough to be detected with the naked eye.
Departamento de Higiene y Tecnología de los Alimentos, Facultad de Veterinaria, Universidad Complutense, Madrid, Spain.
B
B
Perez de Castro
M A
MA
Asensio
B
B
Sanz
J A
JA
Ordoñez
D000626:Aminopeptidases / Q000378:metabolism*; D000814:Aniline Compounds / Q000032:analysis; D000818:Animals; D002417:Cattle; D003080:Cold Temperature; D003470:Culture Media; D005516:Food Microbiology; D006090:Gram-Negative Bacteria / Q000201:enzymology / Q000254:growth & development*; D006863:Hydrogen-Ion Concentration; D008460:Meat; D012034:Refrigeration; D013053:Spectrophotometry; D013552:Swine
D000814:Aniline Compounds; D003470:Culture Media; C019498:4-nitroaniline; D000626:Aminopeptidases