30
Modern Food Microbiology
colonies are often produced. The conditions described as “whiskers” of beef and “black spot” of frozen
mutton are caused by some species. At least one species, M. miehei, is a lipase producer. It is found
in fermented foods, bacon, and many vegetables. One species ferments soybean whey curd.
Penicillium. When conidiophores and conidia are the only reproductive structures present, this genus is
placed in the Deuteromycota. They are placed with the ascomycetes when cleistochecia with ascospores
are formed as either Talaromyces or Eupenicillium. Of the two teleomorphic genera, Talaromyces is the
most important in foods.
37 T. flavus is the teleomorph of P. dangeardii, and it has been involved in the
spoilage of fruit juice concentrates.
27 It produces heat-resistant spores. When conidia are formed in
the penicillus, they pinch off from phialides. Typical colors on foods are blue to blue-green. Blue and
green mold rots of citrus fruits and blue mold rot of apples, grapes, pears, and stone fruits, are caused
by some species. One species, P. roqueforti, produces blue cheese. Some species produce citrinin,
yellow rice toxin, ochratoxin A, rubratoxin B, and other mycotoxins (see Chapter 30).
Rhizopus. Nonseptate hyphae are produced that give rise to stolons and rhizoids. Sporangiophores
typically develop in clusters from ends of stolons at the point of origin of rhizoids. R. stolonifer is by
far the most common species in foods. Sometimes referred to as “bread molds,” they produce watery
soft rot of apples, pears, stone fruits, grapes, figs, and others. Some cause “black spot” of beef and
frozen mutton. They may be found on bacon and other processed meats. Some produce pectinases,
and R. oligosporus is important in the production of oncom, bongkrek, and tempeh.
Thamnidium. These molds produce small sporangia borne on highly branched structures. T. elegans
is the only species, and it is best known for its growth on refrigerated beef hindquarters where its
characteristic growth is described as “whiskers.” It is less often found in decaying eggs.
Trichothecium. Septate hyphae that bear long, slender, and simple conidiophores are produced.
T. roseum is the only species, and it is pink in color and causes pink rot of fruits. It also causes
soft rot of cucurbits and is common on barley, wheat, corn, and pecans. Some produce mycotoxins
(see Chapter 30).
Other Molds. Two categories of organisms are presented here, the first being some miscellaneous genera that are found in some foods but are generally not regarded as significant. These are Cephalosporium, Diplodia, and Neurospora. Cephalosporium is a deuteromycete often found on frozen foods.
The microspores of some Fusarium species are similar to those of this genus. Diplodia is another
deuteromycete that causes stem-end rot of citrus fruits and water tan-rot of peaches. Neurospora is
an ascomycete, and N. intermedia is referred to as the “red bread” mold. Monilia sitophila is the
anamorph of N. intermedia. The latter is important in the oncom fermentation and has been found
on meats. The “white spot” of beef is produced by Sporotrichum spp.; and rots of various fruits
are caused by Gloeosporium spp. Some Helminthosporium spp. are plant pathogens and some are
saprophytes.
Neosartorya fischeri (anamorph Aspergillus fischerianus) was first recognized in the early 1960s as
the cause of spoilage of fruit products. Its ascospores are very heat resistant, being able to withstand
boiling in distilled water for up to an hour. It has a D 87 C of around 11 minutes in phosphate buffer.
Interestingly, it produces several mycotoxins—fumitremorgin A, B, and C; terrein; verruculogen; and
fischerin.
The second category consists of xerophilic molds, which are very important as spoilage organisms. In
addition to Aspergillus and Eurotium, Pitt and Hocking
37 include six other genera among the xerophiles:
Modern Food Microbiology
colonies are often produced. The conditions described as “whiskers” of beef and “black spot” of frozen
mutton are caused by some species. At least one species, M. miehei, is a lipase producer. It is found
in fermented foods, bacon, and many vegetables. One species ferments soybean whey curd.
Penicillium. When conidiophores and conidia are the only reproductive structures present, this genus is
placed in the Deuteromycota. They are placed with the ascomycetes when cleistochecia with ascospores
are formed as either Talaromyces or Eupenicillium. Of the two teleomorphic genera, Talaromyces is the
most important in foods.
37 T. flavus is the teleomorph of P. dangeardii, and it has been involved in the
spoilage of fruit juice concentrates.
27 It produces heat-resistant spores. When conidia are formed in
the penicillus, they pinch off from phialides. Typical colors on foods are blue to blue-green. Blue and
green mold rots of citrus fruits and blue mold rot of apples, grapes, pears, and stone fruits, are caused
by some species. One species, P. roqueforti, produces blue cheese. Some species produce citrinin,
yellow rice toxin, ochratoxin A, rubratoxin B, and other mycotoxins (see Chapter 30).
Rhizopus. Nonseptate hyphae are produced that give rise to stolons and rhizoids. Sporangiophores
typically develop in clusters from ends of stolons at the point of origin of rhizoids. R. stolonifer is by
far the most common species in foods. Sometimes referred to as “bread molds,” they produce watery
soft rot of apples, pears, stone fruits, grapes, figs, and others. Some cause “black spot” of beef and
frozen mutton. They may be found on bacon and other processed meats. Some produce pectinases,
and R. oligosporus is important in the production of oncom, bongkrek, and tempeh.
Thamnidium. These molds produce small sporangia borne on highly branched structures. T. elegans
is the only species, and it is best known for its growth on refrigerated beef hindquarters where its
characteristic growth is described as “whiskers.” It is less often found in decaying eggs.
Trichothecium. Septate hyphae that bear long, slender, and simple conidiophores are produced.
T. roseum is the only species, and it is pink in color and causes pink rot of fruits. It also causes
soft rot of cucurbits and is common on barley, wheat, corn, and pecans. Some produce mycotoxins
(see Chapter 30).
Other Molds. Two categories of organisms are presented here, the first being some miscellaneous genera that are found in some foods but are generally not regarded as significant. These are Cephalosporium, Diplodia, and Neurospora. Cephalosporium is a deuteromycete often found on frozen foods.
The microspores of some Fusarium species are similar to those of this genus. Diplodia is another
deuteromycete that causes stem-end rot of citrus fruits and water tan-rot of peaches. Neurospora is
an ascomycete, and N. intermedia is referred to as the “red bread” mold. Monilia sitophila is the
anamorph of N. intermedia. The latter is important in the oncom fermentation and has been found
on meats. The “white spot” of beef is produced by Sporotrichum spp.; and rots of various fruits
are caused by Gloeosporium spp. Some Helminthosporium spp. are plant pathogens and some are
saprophytes.
Neosartorya fischeri (anamorph Aspergillus fischerianus) was first recognized in the early 1960s as
the cause of spoilage of fruit products. Its ascospores are very heat resistant, being able to withstand
boiling in distilled water for up to an hour. It has a D 87 C of around 11 minutes in phosphate buffer.
Interestingly, it produces several mycotoxins—fumitremorgin A, B, and C; terrein; verruculogen; and
fischerin.
The second category consists of xerophilic molds, which are very important as spoilage organisms. In
addition to Aspergillus and Eurotium, Pitt and Hocking
37 include six other genera among the xerophiles: