Causes, Concerns, Consequences and Control of Microbial Contaminants in Meat-A Review
The aim of this study was to evaluate status of microbial contaminants in food of animal origin. Emergence and re-emergence of diseases due to pathogenic bacteria are the key issue of the new pattern of food trades. Food poisoning or food intoxication syndrome is a global problem for meat industry. The bacterial pathogens most frequently identified from illness associated with beef products are Salmonella sp., Campylobacter, Staphylococcus aureus, Escherichia coli, Listeria monocytogenes, Clostridium perfringens, Yersinia enterocolitica, Bacillus cereus and Vibrio parahaemolyticus. Microbial contaminants rather common than any other form of contaminants as food animals itself harbour them hence, microbial contamination of carcass surfaces is unavoidable. Most of the micro floras transferred to the carcasses are nonpathogenic, but some pathogens like Salmonella sp., Escherichia coli O157:H7, Campylobacter sp. and L. monocytogenes may be present and poses a safety challenge to the meat industry. Novel methods such as immunological, chemical, biochemical, biophysical, nucleic acid probe, Polymerase Chain Reaction (PCR) and more recently biosensor based techniques have been developed to monitor the incidence of pathogenic bacteria in meat foods. In recent years, increase in global trade and awareness of the consumers about the hygienic quality of the meat, international attention is being focused on ways to improve the microbial quality and safety of meat foods. The present review confirmed the importance of maintaining good process hygiene at meat packing plants for further improvement of microbiological status of meat.
The office of the United States Trade Representative has estimated that international
trade has increased fivefold since, signing of General Agreement on Tariff and
Trade (GATT) in 1947. The formation of World Trade Organization (WTO) in 1995
resulted in significantly increased trade in foods of animal origin and live
animals between different countries. But emergence and re-emergence of diseases
due to pathogenic bacteria are the key issue of the new pattern of meat food
trades. According to CDCP (1998) report, annual cost
due to foodborne illness in the United States is nearly 10 billion US$. The
bacterial pathogens most frequently identified from illness associated with
beef products are Salmonella sp., Clostridium perfringens and
Staphylococcus aureus. Interest on Escherichia coli O157: H7 has
increased after highly publicized outbreak of food poisoning associated with
undercooked beef patties in the United States in 1993 though it was confined
to North America until mid 1990s. Likewise, multidrug resistant Salmonella
typhimurium DT-104 spread widely since, they were first detected in United
Kingdom (JECFA, 2002). The incidence of Salmonella
was recorded up to 9% in red meat in India (Rao and Mahendrakar,
2003). These potential bacterial pathogens reside in hide or in intestinal
tract of food producing animals or may be originating indirectly by cross contamination
or through processing environment (Buckle et al., 1989).
Other foodborne emerging diseases include Listeriosis, which spread throughout
the France and also in Canada, where meat and meat products were implicated
as a source of Listeria monocytogenes (Borch and
Arinder, 2002). Similarly, Staphylococcal food poisoning or food
intoxication syndrome was first reported in 1894, it is now a global problem
in meat industry. In this review, we have tried to present the scenario about
meat borne pathogens, the major sources of contamination, their detection, incidences
of pathogen contamination in meat foods, the public health risk and relevant
Foodborne pathogens: Pathogens are virtually inescapable, reaching every
aspect of life. Potentially threatening bacteria in foods, soil and in water
has historically outrun any detection efforts resulting in unwarranted deaths
and illness. Current trends in nutrition and food technology are increasing
the demands on food microbiologist to ensure a safe food supply. Microbial contaminants
are extremely difficult to pinpoint precision of their presence and role in
food systems. Available literature suggests that the evidence of foodborne spoilage
and pathogenic bacteria reported up from pre-scientific era. Lot of developments
has taken place in bacteriology in 1900s and scientists identified a range of
bacteria and now have no limits. Among all the microbes, Salmonella and
Campylobacter are the most serious foodborne pathogens. These two bacteria
are causing as many as 4 million illnesses and 4000 deaths year-1
in USA (Bennett and Berry, 1987). Other important foodborne
pathogenic bacteria include Listeria monocytogenes, Staphylococcus
aureus, Clostridium perfringens, Yersinia enterocolitica, Bacillus
cereus, Escherichia coli and Vibrio parahaemolyticus. Although,
the same food borne pathogens are found in many other countries, risks are different
because of geographical differences in the animals and vector reservoirs, cultural
differences of food consumption habits and processing conditions (ERS,
Sources of microbial contaminants in meat: Microbial contaminants rather
common than any other form of contaminants as food animals itself harbour them.
Microbial status of fresh meat depends on animal rearing, transportation, slaughtering
and cutting and packaging, besides hygiene and processing conditions of the
slaughter plant. The natural surface flora of meat animals usually is not important
as the contaminating microorganisms from their intestinal or respiratory tracts.
However, hides, hooves and hair contain not only large numbers of microorganisms
from soil, manure, feed and water but also important kinds of spoilage organisms.
The skin of many meat animals may contain Micrococci, Staphylococci
and Streptococci. Staphylococci on the skin or from the respiratory
tract may find their way onto the carcass and then to the final raw product.
The faeces and faecal contaminated products of animals can contain many enteric
organisms including Salmonella. People working in meat processing plants
also can act as vector of many foodborne pathogenic bacteria, but this represents
only little importance (Frazier and Westhoff, 1999).
Monitoring of these emerging contaminants and strict implementation of surveillance
contributes positive benefits to importing and exporting countries. These benefits
are improved health and nutritional status, economic advantages through job
creation and improved diplomatic relation between the countries concerned, but
this relies on testing and other forms of inspection by either exporting or
importing country or both.
Detection of microbial contaminants: Currently, so many techniques are
available for enumeration and isolation of microbial contaminants in foods.
But, techniques explained by American Public Health Association (APHA,
1984) and International Commission on Microbiological Specification for
Foods (ICMSF, 1978) for enumeration and isolation of bacteria
are widely acceptable.
However, several novel methods such as immunological, chemical, biochemical,
biophysical, nucleic acid probe, Polymerase Chain Reaction (PCR) and more recently
biosensor based techniques have been developed to monitor the incidence of pathogenic
bacteria in foods including meat (Fung, 1995). Inherent
problems associated with such techniques include difficulties in the recovery
of bacterial species from meat and other foods, as some co-extractive materials
comes at the time of enrichment in selective broth medium or even successful,
they are time consuming to carry out and can significantly extend duration of
the isolation and detection procedure (Duffy et al.,
1999). Inefficiencies in extraction of the target pathogens from the food
matrix and poor separation from elements of the competitive micro flora, can
lead to subsequent problems in the accurate detection and/or differentiation
of target organisms. Thus, co-extractive materials can interfere with DNA hybridization
test in PCR assay and immunoassay (Beumer and Brinkman,
1989). Furthermore, these methods require approval by any Governmental Organization
or other agencies such as CAC, AOAC, APHA, ISO etc. Traditional cultural and
serological methods play a utopian goal in this area of concern, though time
consuming and labour intensive.
Traditional and standardized analysis of food for presence of bacteria relies
on the enrichment and isolation of presumptive colonies on solid media, using
approved diagnostic artificial media. The International Organization for Standardization
(ISO) has elaborated several standards for the detection of important pathogenic
bacteria by traditional method. For example, Salmonella (ISO 6579), Listeria
monocytogenes (ISO 10560), thermo-tolerant Campylobacter (ISO 10272),
E. coli O157 (ISO 16654) and Staphylococcus sp. (ISO 6888) were
enumerated by several workers (Anonymous, 1999, 2001;
Biswas et al., 2008).
Incidences of contaminants in meat: The microbiological profile of meat
products is one of the key criteria for determining quality and safety of fresh
produce. Ideally, meat should be considered as wholesome when pathogen of concerns
is absent or even present at lower number depending on their toxins/metabolites
in per unit basis or food lot. Various researchers had reported microbial contaminants
in meat (Gill, 1998; Vanderlinde
et al., 1998; Biswas et al., 2008).
Vanderlinde et al. (1998) did an extensive study
on microbial quality of beef carcass meat from retail outlets as well as export
markets. In a similar study, Biswas et al. (2008)
reported that buffalo meat from Indian meat packing plant contain comparatively
less number of microbes than many developed and developing country. The log
mean of SPC for frozen buffalo meat trimmings and silver sides were 4.18 and
2.98 g-1. In other study, Ziauddin et al.
(1994) reported that the differences in bacterial counts on the different
regions of the carcasses as well as two slaughter units were marginal. The SPC
of leg, loin, shoulder and neck cuts varies from 4.82-4.92, 4.71-5.13, 5.41-5.49
and 4.52-4.80 log10 cfu cm-2, respectively. In surveys
of seven European abattoirs, Roberts et al. (1984)
reported that mean aerobic plate counts for beef carcasses ranged between 2.29
and 3.85 log units cm-2. Beef carcass from Germany (Ingram
and Roberts, 1976), New Zealand (Keeley, 1988) and
USA (McNamara, 1995) showed average APC of 4.51, 4.51
and 2.68 log cfu cm-2, respectively. However, trimmings had higher
APC than different beef cuts (Scanga et al., 2000).
Streptococcal species are faecal origin and are better indicators of
food sanitary quality, especially for frozen foods. Gill
(1998) reported that potential meat contamination of Streptococcus faecalis
occurred during slaughtering and butchering of food animals. He further revealed
that knife trimming do not contribute to enhancing microbiological quality of
dressed carcasses, except aesthetic values. Chabela et
al. (1999) elucidated that Enterobacteriaceae counts in beef
meat were 105 cfu g-1. The incidence of coagulase-positive
Staphylococcus sp., on both domestic and export beef carcasses in Australia
were 20 and 29%, respectively (Vanderlinde et al.,
1998). But in US beef carcasses, the incidence was only 4.2% (McNamara,
1995). However, incidences of L. monocytogenes in meat vary widely
from 0 to 92% and the contamination mostly occurred on the surface of meat and
meat products (Farber and Peterkin, 1991). The organism
may also thrived interior of muscle tissues of frozen beef. In a survey of 2089
steer/heifer carcasses in the USA, it has been revealed that incidence of
L. monocytogenes was about 4.1%. However, no L. monocytogenes was
reported in beef carcasses from Northern Ireland (Madden
et al., 2001). Though, in India, L. monocytogenes was first
isolated from sheep, later several studies suggested the presence of this organism
in buffalo meat (Chaudhari, 2001; Biswas,
2005; Biswas et al., 2008).
The incidence of Salmonella sp., in food animals is wide. Foodborne
outbreaks of salmonellosis associated with eating of beef have been reported
by Roels et al. (1997). Abouzeed
et al. (2002) have reported the prevalence of Salmonella sp.,
to be 4.6% in beef cattle on conducting examination of caecal contents in Canada.
Patterson (1974) reported that the incidence of Salmonella
sp., was 0.34% in Northern Ireland. Similarly, Vanderlinde
et al. (1998) reported the incidence of Salmonella sp., in
Australian frozen bulk packed meat was 0.22%. Likewise, Scanga
et al. (2000) did a classical study for determination of level of
contaminants in raw beef trimmings and ground meat. In their study, Salmonella
sp., was found more frequently in fed-beef trimmings (5.2%) than culled beef
cow trimmings (0%), culled dairy cow trimmings (0%) or imported trimmings. The
incidences of Salmonella sp., in beef were also reported in the USA (Sofos
et al., 1999) and Mexico (Chabela et al.,
1999). Bachhil and Jaiswal (1988) recorded 5% of
sample of fresh and frozen buffalo meat, 6.6% of minced meat and 10% Kabab were
positive for Salmonella in India.
Escherichia coli, since its discovery by Theobald Escherich in 1885
has been receiving much greater importance due to its pathogenicity by certain
strains both in man and animals. Worldwide contamination of this group of bacteria
occurred in meat through soiling of the carcass and plant environment with faecal
materials during slaughter process (Johnson et al.,
1996). The incidence of E. coli not very variable in domestic or
export beef meat regardless the fat content in trimmings. The average E.
coli Counts (ECC) in Indian buffalo meat were 1.1log cfu g-1.
In another study, Hazarika et al. (2005) screened
153 buffalo meat samples, among which 24.78% samples were positive for E.
coli. However, enumeration data regarding various groups of E. coli
Evidence of VTEC was found in 15 to 40% samples of ground or deboned raw beef
in Canada (Acheson, 1996). Similarly, in the United
Kingdom, 17% of raw beef samples contained VTEC. However, VTEC were found less
frequently in continental Europe and only 1.8% of beef were recorded positive
(Pierard et al., 1994). Elder
et al. (1997) noted that among 28% of cattle presented for slaughter
in Midwestern USA carried E. coli O157:H7, only 2% of carcasses sampled
were positive. Other workers also reported incidences of E. coli (71%
serotype O157) in Sweden (Anonymous, 2000).
Prevalence rate of verotoxic E. coli in meat and meat products has been
recorded at an alarming rate in India. In a study, Rathore
(2000) reported that 89.19% of 37 E. coli isolates were found verotoxic
by vero-cell cytotoxicity assay. Similarly, E. coli strains isolated
from different meat and meat products revealed 15.90% isolates to be verotoxigenic
(Banerjee et al., 2001). Hazarika
et al. (2005) reported that 27% isolates of E. coli were verotoxigenic
(VTEC) in vero-cell cytotoxicity assay. They further concluded that majority
of VTEC isolates from meat and meat products of buffaloes were found positive
for vt2 gene (77.42%) followed by vt1 (16.13%), while
both vt1 and vt2 were detected only in 6.45% of the VTEC
Public health risk: There is considerable evidence of foodborne pathogens,
mainly microbial origin, constitutes major health hazards. Among all the microbes,
Salmonella and Campylobacter are the most serious foodborne pathogens.
These two pathogens are causing as many as 4 million illness and 4000 deaths
per year in USA (Bennett and Berry, 1987). The most
common clinical manifestation of non-typhoid salmonellosis is that of acute
gastro-enteritis with a short and shelf limiting clinical course. Bacteraemia
may occur as a rare complication of any Salmonella infection and can
degenerate into chronic condition such as osteomyelitis, cardiac inflammation
or neural disorders. It has also been linked to one set of aseptic reactive
arthritis and Reiter's syndrome. Severe infection occurs most often in the infant,
elderly or immunocompromised patients. In the person infected with HIV, salmonellosis
can be a severe invasive disease and recurrence of bacteraemic infection after
appropriate therapy is common (Tauxe, 1991). Similarly,
VTEC are associated with infant diarrhoea, hemorrhagic colitis, thrombotic-thrombolytic
purpura and haemolytic uremic syndrome in human. However, E. coli 0157:H7
is most common serotype isolated from individuals with haemorrhagic colitis.
Other important pathogenic bacteria associated with food safety issue is Listeria
and coagulase positive Staphylococcus. Listeriosis can occur in healthy
adults and children, however, the most vulnerable groups include pregnant women,
infants, elderly and immunocompromised persons (Jaradat
et al., 2002). In pregnant women, the infection most commonly produces
a flue like illness, complications often occur in the foetus and newborn, resulting
in miscarriage, still birth or meningitis. In older children and adults, common
symptoms are involvement of central nervous system, pneumonia endocarditis,
localized abscess, skin lesions or conjunctivitis with high mortality rate (Miettinen
et al., 1999). However, S. aureus is also responsible for
a variety of pyogenic skin diseases in man. This organism has also been associated
with osteomyelitis, acute endocarditis, toxic shock syndrome, deep-seated abscesses
in various muscle and organs and staphylococcal scald skin syndrome in newborn
babies. Although, the same foodborne pathogens are found in many other countries,
risks are different because geographical differences in the animals and vectors
reservoirs, cultural differences of food consumption habits and of course processing
conditions (ERS, 1999).
Regulations and international agencies: In contrast to chemical contaminants,
for regulation of microbial contaminants, each country in the world have well
controlled monitoring set-up for meat and meat products. But there is little
apparent connection between public health goals and standards or guidelines
except in general way of reducing or limiting contamination (Todd,
2003). It is evident that no one country has microbial standard for all
commercial foods. Several developed country like USA, UK, Germany, France, Italy
and The Netherlands also come under same catalogue. In a recent comment it is
explained, USDA and FDA also need to do a much better job on regulatory enforcement
and they need better enforcement tools too (Anonymous, 2002).
Several international organizations such as Codex Alimentarius Commission (CAC),
Food and Agricultural Organization/World Health Organization (FAO/WHO) also
keeping their efforts for suitable commitment. International Commission on Microbiological
Specification for Foods (ICMSF), International Organization for Standardization
(ISO), Office International des Epizootics (OIE) and Commission of European
Union (EU) also need to strengthen their commitment on regulatory enforcement
in view of public safety issue and global trade. European Union microbiological
meat standards are shown in Table 1.
The Codex Alimentarius Commission (CAC) is the reference agency of World Trade Organization for disputes involving food. This committee achieved a great deal of international consensus on food export or import inspection and certification system. So, if one country is willing to export meat and meat products to other country, they need regular monitoring of food products according to international standards or guidelines set by that country, since it is scientifically impossible for importing country to inspect or test the safety of all foodstuffs.
However, the importing country can maintain a limited inspection and sampling
program for vigilance against accidental or intentional contamination (JECFA,
In India, regulations of microbial contaminants fall under the aegis of some Government/Non-Government Organization that is responsible for formulation of standards and monitoring their quality. These are, Prevention of Food Adulteration Rules, 1954, Ammendment, 2004; Raw meat (Chilled and frozen) Grading and Marketing Rules, 1991; Bureau of Indian Standard, 1995; Agricultural and Processed Food Export Development Authority (Govt. of India) and Meat Food Products Order, 1973, Ammendment, 1994. Microbiological standards under PFA rules, 1954, Ammended 2004 are shown in Table 2.
|| EU microbiological meat quality standards
|Source: Todd (2003)
|| Microbiological standard under PFA rules, 2004
|Source: MOHFW (2004)
In the process of converting live animals into meat, microbial contamination of carcass surfaces is unavoidable. While, most of the microfloras transferred to the carcasses during the slaughtering process are nonpathogenic, there is possibility that pathogens such as Salmonella sp., Escherichia coli O157:H7, Campylobacter sp. and L. monocytogenes may be present and it represents one of the most critical safety challenges for the meat industry. Moreover, in recent years with the increase in global trade and awareness of the consumers of the hygienic quality of meat, international attention is being focused on ways to improve the microbial quality and safety of foods. However, to evaluate the effectiveness of any intervention strategies, it is necessary to know the microbial status of the product before and after implementation of the intervention. The present review confirmed the importance of maintaining good process hygiene at meat packing plants for further improvement of microbiological status of meat.
1: Abouzeed, Y.M., H. Hariharan, C. Poppe and F.S.B. Kibenge, 2000. Characterization of Salmonella isolates from beef cattle, broiler chicken and human sources on Prince Edward Island. Comp. Immunol. Microbiol. Infect. Dis., 23: 253-266.
2: Acheson, D.W.K., L.L. Lincicome, S. De-Breucker and G.T. Keusch, 1996. Detection of shiga-like toxin producing Escherichia coli in ground beef and milk by commercial enzyme immunoassay. J. Food Prot., 59: 344-349.
Direct Link |
3: Anonymous, 2001. Microbiology of Food and Animal Feeding Stuff-Horizontal Method for the Detection of Escherichia coli O157 (ISO-16654; 2001). International Organization for Standardization, Geneva, Switzerland
4: Anonymous, 1999. Microbiology of Food and Animal Feeding Stuffs-Horizontal Method for the Enumeration of Coagulase Positive Staphylococci (S. aureus and other species), Part I. Technique Using Baird-Parker Agar Medium (ISO-6888-1: 1999). International Organization for Standardization, Geneva, Switzerland
5: Anonymous, 2000. Annual Epidemiological Report. Swedish Institute of Infectious Disease Control, Solna, Sweden
6: Anonymous, 2002. Harkin, rivers, degette introduce mandatory recall legislation. July 25 Press Release.
7: APHA, 1984. Compendium of Methods for Microbiological Examination of Foods. 2nd Edn., American Public Health Association, Washington,
8: Bachhil, V.N. and T.N. Jaiswal, 1988. Occurrence of Salmonella in meats. J. Food Sci. Technol., 25: 310-312.
9: Banerjee, R., K.N. Kapoor, R.K. Agarwal and S. Ghatak, 2001. Verotoxin producing Escherichia coli (VETO) in foods of animal origin. J. Food Sci. Technol., 38: 82-84.
10: Bennett, R.W. and M.R. Berry, Jr., 1987. Serological reactivity and in vitro toxicity of Staphylococcus aureus enterotoxins A and D in rejected can foods. J. Food Sci., 52: 416-418.
11: Beumer, R.R. and E. Brinkman, 1989. Detection of Listeria spp. with monoclonal antibody based enzyme linked immunosorbent assay (ELISA). Food Microbiol., 6: 177-177.
12: Biswas, A.K., 2005. Evaluation of export buffalo meat for some chemical residues and microbial contaminants. Ph.D. Thesis, Indian Veterinary Research Institute, Izatnagar, Bareilly.
13: Biswas, A.K., N. Kondaiah, K.N. Bheilegaonkar, A.S.R. Anjaneyulu and S.K. Mendiratta et al., 2008. Microbial profiles of frozen trimmings and silver sides prepared at Indian buffalo meatpacking plants. Meat Sci., 80: 418-422.
14: Borch, E. and P. Arinder, 2002. Bacteriological safety issues in red meat and ready-to-eat meat products, as well as control measures. Meat Sci., 62: 381-390.
CrossRef | Direct Link |
15: Buckle, K.A., J.A. Davey, M.J. Eyles, A.D. Hocking, K.G. Newton and E.J. Stuttard, 1989. Foodborne Microorganisms of Public Health Significance. 4th Edn., Australian Institute of Food Science and Technology, Australia
16: CDCP., 1998. Preventing emerging infectious diseases: A strategy from 21st century. Overview of update CDC plan. MMWR Recomm. Rep., 47: 1-14.
PubMed | Direct Link |
17: Chabela, M.L.P., G.M.P. Serrano, P.L. Calderon and I. Guerrer, 1999. Microbial spoilage of meats offered for retail sale in Mexico City. Meat Sci., 51: 279-282.
18: Chaudhari, S.P., 2001. Immunodiagnostic potential of PI-PLC virulence marker of L. Monocytogenes in listeric infection in buffaloes. Ph.D. Thesis, Indian Veterinary Research Institute, Izatnagar, India.
19: Duffy, G., O.M. Cloak, J.J. Sheridan, I.S. Blair and D.A. McDowell, 1999. The development of a combined surface adhesion and polymerase chain reaction technique in the rapid detection of Listeria monocytogenes in meat and poultry. Int. J. Food Microbiol., 49: 151-159.
20: Elder, R.O., J.E. Keen, G.R. Siragusa, G.A. Baskoey-Gallagher, M. Koohmaraie and W.W.W. Laegried, 1997. Correlation of enterohaemorrhagic E coli O157 in feaces, hide and carcasses of beef cattle during processing. Proc. Natl. Acad. Sci., 97: 2999-3003.
Direct Link |
21: ERS., 1999. Foodborne Pathogens. ERS., Washington
22: Farber, J.M. and P.I. Peterkin, 1991. Listeria monocytogenes, a foodborne pathogen. Microbiol. Rev., 55: 476-511.
PubMed | Direct Link |
23: Frazier, W.C. and D.C. Westhoff, 1999. Contamination of Foods. In: Food Microbiology, Frazier, W.C. and D.C. Westhoff, (Eds.). McGraw-Hill Publishing Limited, New Delhi, pp: 59-68
24: Fung, D.Y.C., 1995. Whats needed in rapid detection of foodborne pathogens?. Food Technol., 49: 64-67.
25: Gill, C.O., 1998. Microbiological Contamination of Meat During Slaughter and Butchering of Cattle, Sheep and Pigs. In: The Microbiology of Meat and Poultry, Davies A. and R. Board (Eds.). Blackie Academic and Professional, New York, pp: 118-157
26: Hazarika, R.A., D.K. Singh, K.N. Kapoor, R.K. Agarwal, A.B. Pandey and D.N. Rajkumar, 2005. Detection and characterization of verotoxin producing E. coli (VTEC) isolated from buffalo meat. J. Food Safety, 24: 281-290.
27: ICMSF., 1978. International Commission on Microbiological Specification for Foods. Microorganisms in Foods-I. Their Significance and Method of Enumeration. 2nd Edn., University of Toronto Press, Toronto
28: Ingram, M. and T.A. Roberts, 1976. The microbiology of red meat carcass and the slaughterhouse. R. Soc. Health, 96: 270-276.
PubMed | Direct Link |
29: Jaradat, Z.W., G.E. Schutzc and A.K. Bhunia, 2002. Genetic homogenicity among Listeria monocytogenes strains from infected patients and meat products from two geographical locations determined by phenotypic, ribotyping and PCR analysis of virulence genes. Int. J. Food Microbiol., 76: 1-10.
Direct Link |
30: JECFA., 2002. Future Trends in Veterinary Public Health: Report of a WHO Study Group. WHO., Geneva
31: Johnson, R.P., R.C. Clarke, J.B. Wilson, S.C. Read and K. Rahn et al., 1996. Growing concerns and recent outbreaks involving non-O157: H7 serotypes of verotoxigenic Escherichia coli. J. Food Prot., 59: 1112-1122.
Direct Link |
32: Keeley, G.M., 1988. The microbiological status of meat from some typical New Zealand meat slaughtering and processing lines. International congress of meat science and technology, Part B. pp 504-507.
33: Madden, R.H., W.E. Espie, L. Moran, J. McBride and P. Scates, 2001. Occurrence of Escherichia coli O157: H7, Listeria monocytogenes, Salmonella and Campylobacter spp. on beef carcasses in Northern Ireland. Meat Sci., 58: 343-346.
34: McNamara, A.M., 1995. Establishment of baseline data on the microbiota of meats. J. Food Safety, 15: 113-119.
35: Miettinen, M.K., A. Siitonen, P. Heiskanen, H. Haajanen, K.J. Bjorkroth and H.J. Korkeala, 1999. Molecular epidemiology of an outbreak of febrile gastroenteritis caused by Listeria monocytogenes in cold-smoked rainbow trout. J. Clin. Microbiol., 37: 2358-2360.
Direct Link |
36: MOHFW., 2004. Contaminants in foods: Prevention of food adulterationContaminants in foods: Prevention of food adulteration Act 1954, (Ammendment 2004). Ministry of Health and Family Welfare.
37: Patterson, J.T., 1974. Microbiology of frozen meat in 60 lb boxes. Agricultural Research Council, MRI Symposium No. 3, Meat Freezing Why and How?.
38: Pierard, D., Z. Van Damme, D. Stevans, L. Moriau and S. Lauwers, 1994. Detection of Verocytotoxin-Producing Escherichia coli in Meat in Belgium. In: Recent Advances in Verocytotoxin Producing Escherichia coli infection, Kormali, M.A. and A.G. Gaglio (Eds.). Elsevier Science, Amsterdam
39: Rao, D.N. and N.S. Mahendrakar, 2003. Challenges of the quality control of Indian meat and meat products in view of global market. Proceedinds of National Symposium on Impact of Globalization on Indian Meat Iindustry, Dec. 11-12, Indian Meat Science Association, Pondicherry, India, pp: 18-26
40: Rathore, R.S., 2000. Studies on enterohaemorrhagic Escherichia coli with special reference to detection of virulence genes. Ph.D. Thesis, Veterinary Research Institute, Izatnagar, India.
41: Roberts, T.A., W.R. Hudson, O.P. Whelehan, B. Simonsen and K. Olgaard et al., 1984. Number and distribution of bacteria on some beef carcasses at selected abattoirs in some member states of the European Communities. Meat Sci., 11: 191-205.
Direct Link |
42: Roels, T.H., P.A. Frazak, J.J. Kazmierczak, W.R. Mackenzie , M.E. Proctor, T.A. Kurzynski and J.P. Davis, 1997. Incomplete sanitation of a meat grinder and ingestion of new ground beef: Contributing factors to a large outbreak of S. typhimurium infection. Epidemiol. Infect., 119: 127-134.
Direct Link |
43: Scanga, J.A., A.D. Grona, K.E. Belk, J.N. Sofos, G.R. Bellinger and G.C. Smith, 2000. Microbiological contamination of raw beef trimmings and ground beef. Meat Sci., 56: 145-152.
44: Sofos, J.N., S.L. Kochevor, G.R. Bellinger, D.R. Buege and D.D. Hancock et al., 1999. Sources and extent of microbiological contamination of beef carcass in seven United States slaughtering plants. J. Food Prot., 62: 140-145.
Direct Link |
45: Ziauddin, S.K., D.N. Rao and B.L. Amla, 1994. A study of microbial profiles of buffalo carcasses processed in local slaughter units. Ind. J. Comp. Microbiol. Immunol. Infect. Dis., 15: 61-62.
46: Tauxe, R.V., 1991. Salmonella: A postmordern pathogen. J. Food Prot., 54: 563-568.
Direct Link |
47: Todd, E.C.D., 2003. Microbiological safety standards and public health goals to reduce foodborne disease. Meat Sci., 66: 33-43.
48: Vanderlinde, P.B., B. Shay and J. Murray, 1998. Microbial quality of Australian beef carcass meat and frozen bulk packed beef. J. Food Prot., 61: 437-443.
Direct Link |