Jpg. Piette et Jy. Postec, BACTERIAL ADHESION TO SAUSAGE CASINGS - DEVELOPMENT OF A MODEL EXPERIMENTAL SYSTEM, Food research international, 26(4), 1993, pp. 283-287
An experimental system was developed to study bacterial adhesion to co
oked sausages, using natural sheep casing, 100% collagen casing, or co
llagen-sorbitol-cellulose casing as model surfaces. Square pieces (c.
1 cm2) of the casings were inserted into specially designed flow chamb
ers. Bacteria were introduced (c. 10(8) cfu ml-1) and allowed to sedim
ent on the casings for 20 min. The chambers were then rinsed under con
trolled conditions (shear stress of 0.05 N m-2) and the remaining (adh
erent) bacteria were stained and enumerated under light microscopy. Ty
pically, Brochothrix thermosphacta cells adhered to casings in large n
umbers (c. 10(5) cfu cm-2), regardless of the casing type and mode of
rehydration (30 min in water or 5 min in a 10% NaCl solution; room tem
perature). A Lactobacillus sp. was found to adhere to the casings in l
ower numbers (c. 10(4) cfu cm-2) and this was due to a low level of se
dimentation rather than to weak adhesive properties. Preliminary resul
ts indicate that the method developed will be applicable to pieces of
casings peeled from cooked sausages.