156.
NOLI, R I P E I E D F E A T P f i O C l i C T S
J.
C.
AYRES,
E.
A.
LILLARD,
L.
LEISTNEE
Molds or y e a s t s a r e f r e q u e n t l y present i n l a r g e amounts on t h e
surface or i n t h e i n t e r i o r of c e r t a i n aged, cured meats such a s "fermented"
sausages and "country cured" hams and can be metabolically a c t i v e during
t h e long curing and ripening time of t h e s e meats. Provisionally, t h e s e
fungi must be considered important f o r t h e determination of f l a v o r ,
appearance, and wholesomeness of t h e s e meats.
"Fermented" sausages or salami f o r which molds or y e a s t s a r e
b e l i e v e d t o be d e s i r a b l e , a r e t r a d i t i o n a l l y produced i n c o u n t r i e s such
a s Hungary, I t a l y , Spain, Greece, Yugoslavia, Rumania and Czechoslovakia
and, t o a more l i m i t e d e x t e n t , i n c e r t a i n l o c a l i t i e s of t h e U. S . The
processing of t h e s e sausages i n s e v e r a l European c o u n t r i e s has been an
i n d u s t r y f o r hundreds o f years but i s l a r g e l y r e s t r i c t e d i n t h e U. S. t o
t h e San Francisco-Oakland Bay a r e a , where scme t e n manufacturers may be
found. "Country cured" hams a r e dry-cured meats comonly produced i n t h e
southern U. S. and have a curing and ripening time of 1 / 2 t o 2 years.
Heavy mold growth on t h e surface of t h e s e hams, i s o f t e n observed and i s
sometimes rega.rded a s a s i g n of proper aging.
Dry European type salami d i f f e r s from a l l o t h e r sausages i n
t h a t i t s surface i s covered by a l i g h t grey mold mycelium. The microf l o r a not only a f f e c t s t h e appearance b u t a l s o i n f l u e n c e s t h e orgacol e p t i c q u a l i t i e s and weight l o s s e s of t h e product during aging. The
c o n t r o l of mold growth on salami depends almost e x c l u s i v e l y on experience
acquired over many years of p r a c t i c e . Variable proportions of pork and
beef may be used i n t h e formulation of d i f f e r e n t types of fermented
sausages. Usually, no water i s added t o t h e meat and t h e f a t i s i n c o r porated a s d i s c r e t e p a r t i c l e s or p i e c e s t h a t range i n s i z e from 1/8 t o 1/4
inch. Generally, t h e s e cubes a r e c a r e f u l l y mixed w i t h t h e l e a n meat so
t h a t a marbling e f f e c t i s given t o t h e f i n a l product. S a l t , s p i c e s , n i t r i t e
and n i t r a t e a r e added during t h e mixing process. This suspension i s kept
a t 37OF f o r s e v e r a l hours t o allow t h e i n g r e d i e n t s t o mature. Then t h e
sausage i s s t u f f e d i n t o n a t u r a l o r a r t i f i c i a l f i b r o u s casing and hung overnight before cold smoking d a i l y f o r 2 hours f o r 8-10 days (Hungarian
salame). Otherwise, t h e product remains i n a green room f o r 4-5 days
where excess moisture d r i p s from t h e meat tJhi1e a c h a r a c t e r i s t i c mold f l o r a
begins t o grow on t h e casing ( I t a l i a n salame) - t h e t i m e v a r i e s f o r d i f f e r e n t batches and f o r d i f f e r e n t types of sausage. A f t e r smoking or when
v i s i b l e growth i s observed, t h e product i s moved t o an aging room f o r a
f u r t h e r 30 t o 60 day p e r i o d of curing; t h e temperature of t h i s room i s cont r o l l e d a t 50-60°F and humidity a t 75%. Too much humidity i s undesirable
since it r e s u l t s i n excessive mold development and t h e presence of und e s i r e d f l u f f y or darker growth on t h e casings. Curing t h e aging period,
employees p e r i o d i c a l l y check t h e salami f o r mold growth and determine when
t h e sausages a r e mature and ready f o r marketing.
157.
The production of "country cured" hams has been known f o r
many years and t h e procedures adopted have become t r a d i t i o n a l i n
c e r t a i n a r e a s . These processors a r e entrepreneurs who have developed
a product t h a t has a t t a i n e d good l o c a l acceptance. Most of t h e p l a n t s
do not s l a u g h t e r hogs; i n s t e a d they buy t h e hams according t o c e r t a i n
s p e c i f i c a t i o n s from l o c a l packers or from t h e b i g packers. A good,
t h i c k twenty pound ham which i s not t o o l e a n , has a long shank, and a
round c u t b u t t end ( t y p i c a l country ham appearance) i s p r e f e r r e d .
Ordinarily, t h e processing season extends f r o m t h e middle of
November u n t i l t h e middle of January, and t h e e a r l y p a r t of December i s
considered a s t h e b e s t time t o s t a r t curing because t h e n it i s u s u a l l y
c o o l and dry, b u t not s u f f i c i e n t l y cold t o f r e e z e t h e meat. The
temperature should not be above 40°F o r below 32OF. For c u r i n g on t h e
f l e s h s i d e and t h e hock end of each ham, t h r e e t o f o u r tablespoons of
sugar cure i s thoroughly rubbed i n , A f t e r t h i s c u r i n g mixture has
"melted" i n t o t h e ham, which u s u a l l y t a k e s about h a l f an hour, sodium
c h l o r i d e i s massaged on t h e f l e s h s i d e and i s deposited on t h e shank
and t h e a i t c h bone opening: 4-1/2-5 pounds of sodium c h l o r i d e a r e r e commended for a hundred pounds of pork. A f t e r a p p l i c a t i o n of t h e cure,
each ham i s wrapped i n butcher paper and s l i p p e d i n t o a c o t t o n k n i t bag.
A f t e r leaving overnight or f o r s e v e r a l days on t a b l e s o r s l a t s , t h e hams
a r e hung, shank end down, i n t h e ham house f o r six weeks or longer.
Some processors hickory-smoke t h e hams every day or every o t h e r day w i t h
cool hickory smoke f o r one t o t h r e e weeks. The hams s t a y i n t h e smokehouse f o r as long a s it t a k e s t o achieve t h e d e s i r e d c o l o r . The smoking
process i s not regarded a s e s s e n t i a l o r even important f o r t h e f l a v o r of
t h e hams b u t enhances t h e appearance of t h e cured product and i s used t o
promote a d v e r t i s i n g . A f t e r smoking, t h e hams a r e hung i n t h e aging room.
The aging time v a r i e s from a m i n i m u m of s i x months and may
extend t o two years i n duration. The l e n g t h of t h e period t h a t a ham i s
aged depends t o a g r e a t e x t e n t on i t s s i z e and f a t content.
A f t e r two years of aging, t h e hams a r e s t i l l considered of high
q u a l i t y and have i n t e n s e f l a v o r . When hams a r e kept longer t h a n t h i s ,
t h e y a r e considered t o be too dry and s a l t y , The f l a v o r of t h e hams i s
considered s a t i s f a c t o r y only a f t e r t h e product has passed through t h e
warm summer season. During t h i s time, t h e ham w i l l l o s e about 25-30
per cent of i t s o r i g i n a l weight. The temperature i s not c o n t r o l l e d during
t h e aging process b u t t h e r e i s some c o n t r o l of t h e humidity by t h e use of
dehumidifiers on damp s m e r days or by c r o s s v e n t i l a t i o n . Preferably,
t h e hams a r e aged i n t h e dark. During aging, t h e hams a r e not handled o r
permitted t o touch each o t h e r .
There a r e a number of modifications i n processing techniques.
I n s e v e r a l of t h e p l a n t s v i s i t e d , t h e operators expected only a small amount
of mold growth on t h e s u r f a c e o f t h e hams and considered it d e s i r a b l e t o
have none. Ordinarily, however, t h e process r e s u l t e d i n a very heavy mold
growth on t h e f l e s h s i d e of t h e ham and, w i t h some processors, presence of
t h e s e molds i s considered an i n d i c a t i o n of proper curing and aging. Yet,
t o o much mold growth was reported t o l e a d t o musty f l a v o r and p e n e t r a t i o n
of t h e molds through cracks i n t o t h e i n t e r i o r of t h e ham.
158.
TABLE 1.
Number and o r i g i n of samples studied.
Fermented sausages
No.
44
43
U. S. A.
bngary
Italy
Spain
Holland
Germany
Swit z e r land
Greece
Rumania
Yugoslavia
Czechoslovakia
Country cured hams
20
5
5
5
2
1
1
1
1
1
M i s sour i
Kentucky
Iowa
Virginia
Tennessee
North Carolina
Georgia
Country cured bacon
3
13
12
11
4
2
M i ss o u r i
Kentucky
Georgia
1
1
1
1
1
1
Ninety samples of c u e d and aged meats were t e s t e d i n t h i s
l a b o r a t o r y f o r c h a r a c t e r i s t i c fungal f l o r a . Most of t h e s e meats were high
q u a l i t y , gourmand-type products f o r which fungi a r e believed t o be
desirable.
The samples analyzed include a l l major t y p e s of cured and aged
meats of t h e U. S. and Europe w i t h which fungi a r e comnonly a s s o c i a t e d .
I n a d d i t i o n , a Yorkshire bacon (England) was examined b u t was not b e l i e v e d
t o have a c h a r a c t e r i s t i c f l o r a . I n a l l , 670 fungal s t r a i n s were i s o l a t e d
(456 molds and 214 y e a s t s ) . It i s b e l i e v e d t h a t t h e fungi i s o l a t e d a r e
r e p r e s e n t a t i v e of t h e y e a s t and mold f l o r a . This view i s supported by t h e
observation t h a t t h e f u n g a l f l o r a i s o l a t e d from products obtained from
d i f f e r e n t l o c a l i t i e s b u t of t h e same type, proved t o be q u i t e s i m i l a r .
Apparently, cured and aged meats provide a s u b s t r a t e s u i t a b l e only f o r
c e r t a i n species of cosmopolitan y e a s t s and molds.
Table 2‘ gives t h e moisture and f a t contents of various sausages.
Sausages made i n t h e U. S. were not as d r y a s those obtained from Europe.
Except f o r t h o s e from I t a l y and Greece, t h e f a t content was similar. These
two sausages were q u i t e greasy and had l a r g e chunks of f a t t h a t had a
yellow appearance due t o t h e discolored l i p i d s .
Yeasts were found t o be more commonly a s s o c i a t e d w i t h fermented
sausages t h a n w i t h country cured hams and were more prevalent on t h e
surface t h a n i n t h e i n t e r i o r of t h e s e products. Yeasts were found on t h e
surface of about 2/3 of t h e hams and 90% of t h e sausages sampled while
t h e y were found i n t h e i n t e r i o r of 1/4 of t h e hams and 1 / 2 of t h e sausages
examined. Although y e a s t s were recovered from high q u a l i t y products, i f
t h e y were present i n excessive amounts ( g r e a t e r t h a n f i v e m i l l i o n per
gram), t h e y c o n t r i b u t e d t o s p o i l a g e (Table 3).
Salami obtained from Hungary and Holland were c h a r a c t e r i z e d by
heavy mold growth on t h e casing of t h e product while mold growth on
genuine I t a l i a n salami w a s somewhat scanty. Yet, sausages from t h e San
Francisco a r e a , although l a b e l e d as I t a l i a n t y p e salami, showed heavy mold
growth on t h e surface.
159.
TABLE 2.
Fat and moisture content of fermented sausages.
Per cent moisture
Per cent f a t *
Spain
28.3
58.9
Spain
17.7
46.7
Spain
22.2
25.9
Italy
25.1
73.4
Italy
23.9
44.5
18.3
70.2
Yugoslavia*
18.9
55.8
H w a r F
20.3
62.5
Rumania**
17.9
55.6
Czechoslovakia*
19.7
59.6
California
32.2
41.6
California
35.0
49.2
Greece
*
**
*
Calculated on dry weight basis
Somewhat dehydrated during t r a n s p o r t a t i o n and storage
160.
Table 3.
Yeasts recovered from 78 ham and sausage samples.
No. of
samples
44
17
Genus
Debaryomyce s
Candida
No. p o s i t i v e
Species
kloeckeri
subglobosus
hans e n i i
n i c o t ianae
Hams
-
Sausages
16
5
12
12
3
4
8
17
8
7
8
10
0
rugosa
reukauf ii
lipolytica
me l i b i o si
c a t enulat a
guilliermondii
2
0
2
1
0
0
5
0
0
1
1
Total
28
5
2
1
1
1
9
Torulopsis
famata
pinus
3
0
5
1
1
2
Saccharomyces
globosus
0
2
2
2
Rhodot o r u l a
muc i l a g ino sa
minuta
1
2
0
0
2
2
Sporob olomyces
roseus
pararoseus
0
1
1
0
1
1
1
Bullera
alba
1
0
1
1
Pichia
unidentified
0
1
1
8
1
Molds were recovered f r o m t h e s u r f a c e of a l l hams examined and
a l s o were d e t e c t e d i n t h e i n t e r i o r of e i g h t hams. Three o f t h e s e hams showed
deep cracks i n t h e i r s u r f a c e , through which t h e mold had penetrated i n t o
t h e i n t e r i o r of t h e hams. The amount of mold growth of t h e s u r f a c e of t h e
country cured hams examined v a r i e d considerably and apparently was i n fluenced by t h e r e l a t i v e humidity a t which t h e hams were held during t h e
r i p e n i n g period. I n general, hams wrapped i n paper during t h e curing and
r i p e n i n g process and kept a t ambient humidity e x h i b i t e d abundant mold
growth on t h e meat p o r t i o n of t h e i r s u r f a c e w i t h l e s s on t h e s k i n and f a t
p o r t i o n s . Hams which were not wrapped i n paper and were held a t a low
r e l a t i v e humidity (about 65%):during ripenLng developed only sparse mold
growth. The f a t on t h e s u r f a c e of t h e s e hams appeared s t r o n g l y oxidized
a f t e r s e v e r a l months of ripening, and t h i s r a n c i d i t y may have c o n t r i b u t e d
t o t h e i n h i b i t i o n of mold growth. (Table 4)
161.
Table 4.
Molds recovered f r o m t h e 67 ham and sausage samples.
Fzmily
No. and $
o f samples
No. of Sam-des
Genus
Hams
Sausages
3
Nucoraceae
9 (135)
Rhizopus
Mucor
5
Mortierellaceae
2 ( 3%)
Mort ier e l l a
1
Cephalidaceae
1 (
Syncephalastrum
1
Moniliaceae
Dematiaceae
15)
66 (99%)
1 4 (21%)
Tuberculariaceae
3 ( 4%)
Unidentified
4 ( 6%)
0
Total
8
1
1
0
1
Penicillium
Aspergillus
Scopular h p s i s
Paecilomyces
Oospora
33
36
3
24
9
11
57
45
14
3
3
Cladosporium
Alternaria
12
0
12
5
3
0
0
3
Epicoccum
Fusarium
3
3
5
1
0
0
0
1
Molds o f t h e family Moniliaceae were t h e most abundant and
g e n e r a l l y outnumbered o t h e r molds p r e s e n t . P e n i c i l l i a were recovered from
about a l l of t h e sausages and hams i n v e s t i g a t e d . On sausages, p e n i c i l l i a
p r e v a i l during t h e e n t i r e ripening process o r share predominance w i t h
Scopulariopsis i n t h e l a t e r s t a g e s . On hams, p e n i c i l l i a are predominant
e a r l y i n t h e r i p e n i n g process, b u t a f t e r longer aging a r e succeeded by
a s p e r g i l l i . (Table 5 ) . This d i f f e r e n c e i n p a t t e r n between sausages and
hams i s probably due t o t h e water a c t i v i t y of t h e s u b s t r a t e s . From
experimental a, determinations it was learned t h a t a f t e r a s h o r t r i p e n i n g
time, fermented sausages have a water a c t i v i t y of about 0.985, which
decreases t o about 0.915 i n t h e f u l l y matured product. On t h e o t h e r hand,
t h e s u r f a c e zone of f u l l y matured country cured hams has an a, of about
0.88.
Molds of t h e genus Aspergillus were recovered from most of t h e
hams b u t only from 1/3 of t h e sausages examined. The A . glaucus group,
which t h r i v e s a t a r e l a t i v e l y low awl was g e n e r a l l y d e t e c t e d on sausages
only i f l i t t l e o r no growth of p e n i c i l l i a was p r e s e n t , b u t was recovered
from almost a l l country cured hams during t h e r i p e n i n g process. I n
a d d i t i o n t o t h e decrease of %, t h e i n c r e a s e i n temperature, applied a f t e r
two t o four months i n ham ripening, could a l s o favor a s p e r g i l l i i n t h e
l a t e r s t a g e s of t h e ripening process. O f t h e species belonging t o t h e A.
glaucus group, A_. ruber, repens and amstelodami were f r e q u e n t l y found.
162.
Table 5.
Penicillia recovered fromthe 67 ham and sausage samples.
No. and %
No. and %
of sausages
34
18
17
9
10 (40%)
18 ( 7 0 5 )
of samples
Series
expansum
janthinellum
chrysogenum
commune
viridicatum
cyclopium
roqueforti
citrinum
frequentans
brevi- compactum
urticae
javanicum
purpurogenum
Rmigena
unidentified
(51%)
(27%)
(25%)
(13$)
6 ( 9%)
5 ( 7%)
4
4
3
3
24
0
12
7
6
5
3
5 (19%)
2 ( 7%
0
0
1
3
1
9 (13%)
(60$)
(30$)
(18%)
(15%)
(13%)
1
3
2
0
1
1
1
8 (20%)
0
3
1
1
1
No. and %
of hams + bacon
3
0
0
0
1 ( 4%)
Table 6.
Aspergilli recovered fromthe 67 ham and sausage samples.
No. of
samples
Aspergillus
group
Species
No. of Samples
Hams
42
glaucus
A. ruber
A. repens
A. amstelodami
A. chevalieri
A. pseudoglaucus
A. mangini
31
A. penicilloides
Sausages
Total
34
1
1
4
3
2
1
1
0
0
6
0
6
27
9
29
10
5
1
1
6
restrictus
7
versicolor
7
0
7
5
niger
3
2
5
2
wentii
2
0
2
1
candidus
0
1
1
1
fumigatus
1
0
1
1
flavus
0
1
1
163.
A.
- -ruber i s apparently t h e most important species of f u l l y matured
country cured hams, s i n c e t h i s species was not only recovered from
every ham examined w i t h a ripening time of longer t h a n f o u r months, b u t
was a l s o p r e s e n t i n very l a r g e amounts. Besides t h e A. glaucus group,
t h e groups A. r e s t r i c t u s and v e r s i c o l o r apparently fiEd a s u i t a b l e subs t r a t e on cured and aged meats. (Table 6 )
The p r i n c i p a l fungal f l o r a of cured and aged meats was
composed of t h e genera Penicillium, A s p e r g i l l u s , Scopulariopsis,
Debaryomyces, Candida and Torulopsis and t h e species of t h e s e genera
which grow r e a d i l y have i n common a t o l e r a n c e f o r l o w water a c t i v i t y .
Further e f f e c t s fhngi might have on fermented sausages or
country cured hams concern t h e f l a v o r or t h e appearance of t h e s e products.
The "mold of choice" might only prevent t h e growth of undesirable molds
and b a c t e r i a on Hungarian type sausage, t h u s i n d i r e c t l y improving t h e
flavor.
A d e s i r a b l e e f f e c t on t h e appearance of t h e product might be
t h a t produced by y e a s t s which reduce myoglobin and t h u s c o n t r i b u t e t o
t h e a t t r a c t i v e , b r i g h t r e d c o l o r of I t a l i a n salami. The development of
v i s i b l e yeast growth ( f l e u r du saucisson) on fermented sausages i s sometimes regarded a s a s i g n of proper ripening.
While l a r g e numbers of y e a s t s i n t h e i n t e r i o r of country cured
hams can c o n t r i b u t e t o spoilage, molds t h a t grow on t h e s u r f a c e of
country cured hams prevent o x i d a t i o n of t h e f a t , which t h e r e f o r e does not
appear yellow o r rancid. Nolds of t h e genus Cladosporium produce und e s i r a b l e "black s p o t s " on meats, while Scopulariopsis cause "white s p o t s "
on t h e s k i n of country cured hams. "Whiskers" on sausages and hams a r e
due t o t h e mycelium growth of Yiucorales, such a s Rhizopus. Cellulosereducing molds b r i n g about d e f e c t s i n c e l l u l o s e casing of sausages, which
render t h e product unsightly. Some producers of country cured hams
expressed t h e opinion t h a t good hams show a dark green mold on t h e surface.
I n o c u l a t i o n Studies
Fungi t o be considered as inocula f o r cured and aged meats
should grow r e a d i l y on o r i n t h e s e products and must be n e i t h e r pathogenic nor toxinogenic.
The f i r s t experimental batch of salami was s t u f f e d i n 3-1/2 inch
diameter f i b r o u s casing and hung i n a green room where t h e temperature was
s e t a t 3OoC and humidity a t 75%. The salami turned a b r i g h t r e d c o l o r
a f t e r 1-1/2 days r a t h e r t h a n i n t h e 4-5 days experienced i n t h e i n d u s t r y .
These salami were smoked f o r e i g h t hours and, s i n c e they were smaller t h a n
t h e commercially produced sausages, t h e y were showered f o r only one hour
w i t h t a p water. For i n o c u l a t i n g t h e surface of t h e salami, molds t h a t
were found on Hungarian salami were s e l e c t e d . Two s t r a i n s of P e n i c i l l i u m
simplicissimum, two of P e n i c i l l i u m expansum and two of Scopulariopsis
alboflavescens were used. Nolds d r i e d and ground a f t e r growing on bread
crumbs were mixed i n a s o l u t i o n containing 0.2% agar and 0.002% Na
s u l f i t e and each salami w a s r o l l e d i n t h e s o l u t i o n containing t h e mold and
hung up. By t h i s method, t h e salami received an even covering which clung
t o t h e skin.
164.
The salami were kept a t 10°C and 75% humidity. There was good
e x t e r i o r growth and even coverage. Salami were t e s t e d a f t e r 1, 2, and 3
months. Each of t h e s e salami l o s t some weight d u r i n g s t o r a g e . On t h e
salami sampled a t one month, t h e r e was no v i s i b l e surface growth. However, upon p l a t i n g , t h e inoculated species grew on t h e media even though
t h e y had not grown on t h e salami used. The inoculated y e a s t d i d not
survive t h e heat used f o r smoking. The color of t h e salami was dark pink
and t h e edges darker; t h e t e x t u r e was dry and t h e r e were some a i r pockets
where t h e casing had not been t i g h t l y s t u f f e d . Also, t h e s a l t added was
i n s u f f i c i e n t and t h e f a t content was low. (Table 7 ) .
Table 7.
Moisture and f a t content of experimental salami (Batch No. 1).
1 mo.
0
%
H20
Sample
Initial
62.8
3 mo.
4'0
%
fat
-
fat
41.2
Control
44.3
39.9
39.0
37.2
P. expansum
48.1
40.6
38. a
37.2
P. simplicissimum
45.4
40.4
37.8
37.9
S. alboflavescens
44.3
41.4
36.3
35.8
All t h r e e molds
48.8
40.6
38.0
37.2
The c e n t e r of t h e salami had b e t t e r f l a v o r t h a n a r e a s near t h e casing.
When t h e s e salami were c u t open, t h e a i r pockets were covered w i t h mold
growth. This i n t e r i o r mold growth could account for t h e l a r g e r degree of
l i p o l y s i s i n some samples.
Since t h e s t u f f i n g of t h e f i r s t b a t c h of salami was f a u l t y ,
a second l o t of e i g h t e e n salami were made and divided i n t o t h r e e groups:
I.
11.
111.
Control
Inoculated w i t h Penicillium simplicissimum Ml51, M16
Inoculated w i t h Penicillium expansum Ml.49, Ml93
For t h i s t r i a l , 10% a d d i t i o n a l f a t was added as before,
b u t t h e q u a n t i t y of s a l t was increased. The meat p a s t e was divided so
t h a t y e a s t c u l t u r e and paprika were i n one h a l f and s p i c e s and curing
i n g r e d i e n t s i n t h e o t h e r . A f t e r mixing, t h e two types of salami were
s t u f f e d i n t o n a t u r a l casings a t high speed. The same y e a s t s were used f o r
t h i s salami a s before.
Samples t a k e n before and a f t e r smoking showed t h a t t h e
inoculated y e a s t d i d not survive t h e temperature i n t h e smoke house. The
165.
t e x t u r e of t h e second b a t c h of salami was much b e t t e r t h a n t h e f i r s t and
t h e added f a t and s a l t improved t h e t a s t e , The salami before smoking had
a pH of 5.5 and a f t e r smoking a pH of 5.0. There was no d i f f e r e n c e i n t h e
c o l o r between t h e group containing s p i c e s only and t h e group having y e a s t s ,
spices and paprika.
-
Hams. Representative c u l t u r e s of fungal strains found on t h e
e x t e r i o r of country cured hams were chosen, and s l a n t s were made of each
s t r a i n f o r i n o c u l a t i o n on t h e e x t e r i o r of t h e hams. S t r a i n s of A s p e r g i l l u s
and Penicillium were s e l e c t e d a s r e p r e s e n t i n g t h e predominant molds found
on t h e e x t e r i o r o f country cured hams. Cultures used were:
Aspergillus ruber: 1472, Ml78
A s p e r g i l l u s repens: M68, M128
Penicillium expansum: Ml16, Ml30
Penicillium chrysogenum: M166
Penicillium
viridicatum:
Ml64, M218
and treatments used a r e given i n Table 8.
Table 8.
Treatment of t h e hams.
Numbers
Weight ( l b s . )
Lbs. of S a l t (5%)
1-8
9-16
17-24
25-32
17-1-21.0
18.9 - 20.9
18.8-20.9
18.6-20.8
.86-1.05
.94-1.06
.94-1.04
.93- 1.04
33
20.6
No ne
Salted controls
Penicillium
Aspergillus
Penicillium
and A s p e r g i l l u s
I n i t i a l unsalted
control
Thirty-three f r e s h hams were obtained from a packing company
from pigs t h a t had been slaughtered t h e day before and t h e meat had been
allowed t o remain r e f r i g e r a t e d overnight. They were about 20 pound hams long shanked and unskinned. The b u t t end of 32 of t h e hams was trimmed,
and t h e n each hamwas weighed. Five pounds of s a l t per 100 pounds of
meat were used f o r rubbing i n t o t h e hams. Sugar, n i t r a t e , or n i t r i t e were
not added, nor were t h e hams smoked. Appropriate amounts of s t e r i l e s a l t
were rubbed i n t o each of t h e hams which were t h e n wrapped i n white butcher
paper and placed i n s t e r i l e k n i t bags.
Except for t h e u n t r e a t e d c o n t r o l , t h e 32 hams were kept a t O°C
f o r one night and then were moved i n t o t h e c o n t r o l l e d humidity box and
hung, shank down, where they were allowed t o remain under c o n t r o l l e d
conditions (Table 9 ) . Two of t h e hams from each group were removed and
sampled a t t h r e e month i n t e r v a l s during t h e curing time of one year.
A f t e r two weeks curing time, one of t h e e i g h t hams w i t h s a l t
b u t no inoculum was examined f o r e x t e r i o r f l o r a t o o b t a i n an i d e a of which
b a c t e r i a had survived t h e high s a l t content. Only t h r e e a r e a s were sampled
and t h e procedure was t h e same as t h a t used for t h e s u r f a c e sampling of
f r e s h ham No. 33.
166.
Table 9
Procedure f o r curing hams.
Days
Temperature
Relative Humidity
60
4%
l0OC
88%
80%
30
90
90
75%
72%
2O0C
3OoC
The o u t s i d e of t h e f r e s h ham was found t o have two species of
P e n i c i l l i u m and one of Aspergillus t o g e t h e r w i t h two s t r a i n s of s o i l
Sarcina, Micrococcus spp., and B a c i l l u s spp.
fungi and some b a c t e r i a
The i n t e r i o r of t h e ham contained about t h e same f l o r a w i t h t h e exception
t h a t one y e a s t species was found and t h e r e were no Sarcinae.
-
When t h e c o n t r o l ham was sampled a f t e r two weeks of curing
time, it was found t h a t t h e same t y p e s of organisms were p r e s e n t a s those
a t t h e beginning. This would i n d i c a t e t h a t t h e s e could withstand t h e
high s a l t content. The appearance of t h e ham a t t h i s time w a s bloody
and caked w i t h s a l t ; no mold growth was v i s i b l e .
Upon sampling f o r i n t e r i o r growth, t h e ham was cut t h r e e times
perpendicular t o t h e femur; t h e s u r f a c e of each cut was flamed, and 30
grams of m a t e r i a l were removed a s e p t i c a l l y f r o m w i t h i n each s l i c e . These
represented compact muscle, connective t i s s u e , and f a t . A bone marrow
sample was a l s o t a k e n f r o m t h e femur i n t h e middle s l i c e of t h e ham. Each
of t h e samples was blended and d i l u t e d and p l a t e d on t h e same media a s
l i s t e d for t h e c o n t r o l .
Table 10.
Percentage weight loss of hams.
1.
2.
3.
4.
Control
P. expansum, P. chrysogenum, P v i r i d i c a t u m
A. ruber, A. repens
A l l of t h e above
3 mo.
-
6 mo.
9 mo.
12.9
12.4
13.0
13.3
20.5
22.1
25.1
27.4
24.5
22.4
26.0
28.3
A f t e r s t o r a g e f o r t h r e e months, t h e meat had l o s t 12-13% of i t s
o r i g i n a l weight (Table 10). While t h e o u t s i d e had darkened considerably,
near t h e c e n t e r it s t i l l had a q u i t e f r e s h appearance and. t h e f l e s h was
not very firm. The f a t on t h e c o n t r o l hams had a decided yellow c a s t ,
b u t t h e hams t h a t received inocula containing p e n i c i l l i a were much w h i t e r
and had l e s s r a n c i d odor. While t h e f a t of t h e meat inoculated w i t h
a s p e r g i l l i a l s o was somewhat rancid, t h e f a t was l e s s colored t h a n t h a t
o f t h e c o n t r o l s . There was q u i t e a l o t of excess s a l t t h a t remained
caked i n t h e depressed a r e a near t h e a i t c h bone.
167
There was l i t t l e mold growth on t h e uninoculated c o n t r o l s ; y e t ,
Penicillium v i r i d i c a t u m was recovered from both hams. On hams t h a t
received inocula containing E. expansum and P. viridicatum, f a i r l y heavy
grey and green growth of t h e s e s p e c i e s was
evidence
especially i n
t h e l e a n a r e a s , P. -was
not recovered. Some growth of P.
expansum and P. v?ridicatum was observed on hams t h a t received i n o c c l a
Apparently t h e high water a c t i v i t y l e v e l of t h e
of aspergilli-only.
meats prevented growth i n i t i a t i o n by e i t h e r of t h e a s p e r g i l l i . A few
species of Micrococcus and B a c i l l u s were recovered f r o m t h e hams
(Table 11).
in
-
Table 11.
Changes occurring i n hams during storage.
3 mo.
6 mo.
Salt
Nold Growth
Control
3P
ZA
3P, 2A
+++
++
++
++
2P ++
2P +
2P ++
-
+
+
+
+
Control
3P
2A
+
+
+
+
2 F + , U+
+++
+
+
+
+
lP, U, X +
3P, 2A
9 mo.
Control
3P
2A
3P, 2A
2P +++
ZP, IA ++
2P,
u ++
2p ++++
2P, 2A +++
2P, 2A ++++
Firmness Amt. Yellow
+++
+++
+++
+++G
++++
++++
++++
Rancidity
+-t
+
+
+
++++
++
++
++
+
+
+
++++T
++++
+++
++
+++
+++
++
++
+
*P.
- expansum and chrysogenum
G = greasy; T = t r a n s l u c e n t
A t s i x m n t h s , t h e hams were q u i t e red and much more f i r m
t h a n a t t h e start, although t h e r e was s t i l l some caked s a l t t h a t remained
undissolved. A s b e f o r e , t h e r e was very l i t t l e mold growth on t h e c o n t r o l s
and the f a t of t h e s e hams was q u i t e yellow and rancid. By c o n t r a s t , t h e
f a t of t h e hams t h a t were inoculated w i t h p e n i c i l l i a had not become much
more r a n c i d or yellow t h a n a t t h r e e months. There was profuse mold growth
on t h e l e a n p o r t i o n s b u t not on t h e s k i n , The hams inoculated w i t h
a s p e r g i l l i or w i t h a s p e r g i l l i and p e n i c i l l i a had considerable mold growth.
While much of this was due t o 2. expansum and 2. viridicatum, A s p e r g i l l u s
ruber was r e a d i l y i s o l a t e d . No b a c t e r i a were recovered from t h e s u r f a c e
of any of t h e hams b u t a few Micrococcus, B a c i l l u s and y e a s t s were i s o l a t e d
f r o m t h e i n t e r i o r samplings. P. chrysogenumwas recovered from t h e uninoculated c o n t r o l s but not f r o m hams r e c e i v i n g t h i s species as p a r t of
an inocula.
By nine months, t h e meat of t h e hams had become q u i t e red and
very f i r m . The c o l o r and firmness were t y p i c a l of country cured hams
e s p e c i a l l y t h o s e inoculated w i t h b o t h t h e Penicillium and A s p e r g i l l u s s t r a i n s .
-
168.
-
The f a t was decidedly yellow and rancid smelling
e s p e c i a l l y on t h e
c o n t r o l s . Mold gmwth was abundant and was present i n f a i r l y l a r g e
amounts even on t h e shank p o r t i o n . Penicillium expansum and Penicillium
v i r i d i c a t u m again were t h e predominant fungi w i t h A s p e r g i l l u s ruber and
A s p e r g i l l u s repens a l s o appearing a s a r e s u l t of t h e considerably lower
water a c t i v i t y . No b a c t e r i a were found on t h e s u r f a c e of t h e hams while
only a few B a c i l l u s , Micrococcus and y e a s t s were found on t h e i n t e r i o r .
This would i n d i c a t e t h a t t h e s a l t concentration and. decreased water
a c t i v i t y were i n h i b i t o r y t o a g r e a t e x t e n t .
Conclusions
On t h e basis of t h e s e f i n d i n g s , it may be concluded t h a t
fungi do p l a y a r o l e i n t h e p r e s e r v a t i o n of aged sausages and hams.
Their c o n t r i b u t i o n t o r e t e n t i o n of moisture and c o l o r has been noted
f o r both types of meat. The use of molds i s i n t e n t i o n a l f o r many
European gourmand sausages b u t i s i n c i d e n t a l f o r most country cured
hams.
Salami overgrovrn by molds develop an a t t r a c t i v e greyish white
f e l t - l i k e surface t h a t p r o t e c t s t h e meat from spoilage fungi and serves
a s a f a i r l y impermeable coating t o moisture vapor and oxygen transmission.
A s a consequence, t h e s e sausages r e t a i n more moisture, develop more i n t e n s e c o l o r , have reduced estraneous microbial growth and can be preserved f o r longer t i n e s without development of r a n c i d i t y .
Hams cure s a t i s f a c t o r i l y without any mold a c t i v i t y but when
t h e s e meats remain i n storage f o r 6-9 months and l o s e 25-30$ of t h e i r
o r i g i n a l weight, growth of P e n i c i l l i a and A s p e r g i l l i appear a s a r e s u l t
o f t h e reduced water a c t i v i t y . The f a t of t h e s e hams i s l e s s yellow and
r a n c i d t h a n t h a t of meat f r e e of mold growth.
DR. BLUMER: O u r next speaker i s Director of Research of John
Morrell and Company. So, he w i l l make a few remarks concerning t h e paper
which was presented by Dr. Deibel. D r . Brown.
DR. BROkJN: Thank you, Tom. I t ' s always a pleasure t o be
back and meet w i t h you. I was very much i n t e r e s t e d i n hearing D r .
D e i b e l ' s paper. This w i l l give me a chance t o t a l k t o you f o r a few
minutes about some s p e c i f i c t h i n g s t h a t we do t o c o n t r o l t h e microbial
content of f i n i s h e d products. I won't t a l k about t h e animal we
s l a u g h t e r ourselves, because we have r a t h e r good c o n t r o l from t h e l i v e
animal a l l t h e way through t o t h e f i n i s h e d product. But we buy a l o t
of meats from o u t s i d e ; we c a l l t h e s e extra-purchase meats. W
e have our
own intercompany s p e c i f i c a t i o n for t h e s e inccming n e a t s .
Now we found out long ago t h a t you c a n ' t give numbers t o your superv i s o r y and operating people t o use. So, you d o n ' t r e p o r t r e s u l t s t o
them on t h e s e meats a s so many p e r gram. You simply send them a r e p o r t
a f t e r t h e m e a t has been p r o p e r l y sampled and t h e a n a l y s i s has been made.
You say t h a t it i s very good, good, questionable, or excessive. We