(6) Bacterial greening. Surface discoloration of sausages and other cured
meats caused by bacteria is common.
(a) The bacteria are deposited in the surfaces during the usual
handling procedures following heat processing. If suitable environmental conditions are
provided, these bacteria grow rapidly on the surface and discolor the cured meat
pigment through hydrogen peroxide accumulation.
(b) Several kinds of bacteria are capable of producing a greenish
discoloration of meat pigment. They include the following genera: Lactobacillus,
Leuconostoc, and Pediococcus.
(c) Bacterial greening of meat surfaces is a direct reflection of
malpractice in sanitation and/or holding conditions of the finished product.
Contamination occurs usually as the result of direct contact with equipment, employees,
or another product harboring the microorganisms.
(d) Following contamination, if the product is held in an environment
that maintains a moist surface and a suitable growing temperature, the discoloration
becomes apparent. Discoloration is usually accompanied by a slimy surface, caused by
heavy bacterial growth.
e. Interior Discolorations. The following interior discolorations may be
observed in meat and meat products.
Overcure or undercure.
(a) An excess of nitrite, especially in the fermented sausages, may
result in a greenish core, which is apparent at the time of cutting the sausage. Green
cores may also accompany surface greening from nitrite burn.
(b) Conversely, insufficient nitrite may result in a faded interior of a
cured meat. This condition is seen in hams and sometimes results from a rupture of the
vascular system at the time of pumping the ham with curing pickle. In this event, there
may be a portion of the ham which never receives a sufficient quantity of the curing
Green rings and cores.
(a) Green rings in sausages are known to be of bacterial origin,
although the exact mechanism of their formation is unknown. The rings appear at
varying depths beneath the surface, usually 2 to 4 mm, and may be of varying
thicknesses. They are apparent at the time of cutting and tend to fade within a few