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National feed inspection program: Results from 1989 to 2018 for the Salmonella monitoring program for livestock feeds

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Background

This random sampling program is part of the National Feed Inspection Program, and was implemented for the purposes of monitoring the prevalence of Salmonella bacteria in all feeds and feed ingredients. Data are available from domestic and imported feed samples collected by the CFIA from feed mills, farms, and retail establishments, over a period of 29 years from April 1, 1989, to March 31, 2018.

Salmonellosis has a significant impact on society in terms of human illness and economic costs. Human illness most commonly results from eating contaminated foods, which are frequently of animal origin, i.e. meat, milk and eggs. Meat and milk can become contaminated with Salmonella bacteria when faeces from an infected animal come into contact with meat during slaughter or milk during milking. Eggs may become contaminated by contact with faeces from infected hens during laying, or through Salmonella infection of an infected hen's reproductive tract. Salmonella bacteria also cause illness and production losses in animals.

Livestock can become infected with Salmonella bacteria through consumption of contaminated feed. Sources of contamination of feeds include both the raw materials used to prepare the feed and environmental contamination from infected insects, birds, rodents, and other animals that may come into contact with the feed before or after preparation. All feeds may contain Salmonella bacteria but some feeds and feed ingredients, such as rendered products, fish meals, oilseed meals, and mash feeds typically are contaminated with Salmonella bacteria more frequently than others, so these feed types are sampled more repeatedly by the CFIA.

In this monitoring program, the sample analyses to detect and identify the Salmonella bacteria are conducted by the CFIA at the Ottawa Laboratory Carling. Detection of Salmonella in any feed sample is considered as non-compliant and regulatory actions are taken to mitigate the risk of the contaminated feed.

Sample results by fiscal year (April 1 to March 31)

A total of 14,624 samples were collected for analysis under this program from April 1, 1989, to March 31, 2018. Table 1 presents a summary of the number of feed samples tested, and the testing results, by fiscal year. The overall sample compliance level for feed samples collected under this program across all years was 87.8%, with levels ranging from 79.3% to 96.0% per fiscal year. While a trend towards increasing compliance over time appears to be present in these data, this information should not be interpreted as evidence of decreasing Salmonella bacterial prevalence in feeds over the years of this study. Factors such as the number of samples by feed type targeted by this program have changed over the years, making year-by-year result incomparable.

Table 1: Number of feed samples tested for Salmonella by fiscal year (April 1 to March 31) from 1989-90 to 2017-2018; results presented in terms of compliance (Salmonella not detected) or non-compliance (Salmonella detected)
Fiscal year Number of samples Number of non-compliant samples Number of compliant samples Percentage of samples in compliance
1989-1990 779 128 651 83.6
1990-1991 913 184 729 79.9
1991-1992 762 141 621 81.5
1992-1993 918 185 733 79.9
1993-1994 735 152 583 79.3
1994-1995 759 115 644 84.9
1995-1996 702 80 622 88.6
1996-1997 690 72 618 89.6
1997-1998 577 80 497 86.1
1998-1999 578 65 513 88.8
1999-2000 452 53 399 88.3
2000-2001 417 42 375 89.9
2001-2002 388 23 365 94.1
2002-2003 445 28 417 93.7
2003-2004 452 49 403 89.2
2004-2005 417 37 380 91.1
2005-2006 326 23 303 92.9
2006-2007 387 28 359 92.8
2007-2008 418 36 382 91.4
2008-2009 433 37 396 91.5
2009-2010 344 33 311 90.4
2010-2011 339 17 322 95.0
2011-2012 377 15 362 96.0
2012-2013 377 33 344 91.2
2013-2014 331 28 303 91.5
2014-2015 369 34 335 90.8
2015-2016 296 18 278 93.9
2016-2017 302 22 280 92.7
2017-2018 341 28 313 91.8
Total 14,624 1,786 12,838 87.8

Evaluation of feed sample compliance by CFIA area

Table 2 presents a summary of compliance results for the 14,624 samples collected from April 1, 1989, to March 31, 2018, organized by the CFIA area from which the samples were collected. It should be noted that the area where a feed was sampled is not necessarily the same as the area in which the feed was produced. The number of samples collected was proportional to the number of feed producers in each area. Differences in sample compliance levels observed between areas are likely due to regional differences in the types of feeds sampled in these areas, as the prevalence of Salmonella bacteria may differ significantly between different feed types. Table 1 of Appendix I presents compliance results for feed samples by area for each fiscal year (April 1 to March 31).

Table 2: Number of feed samples tested for Salmonella by CFIA area, from April 1, 1989, to March 31, 2016; results presented in terms of compliance (Salmonella not detected) or non-compliance (Salmonella detected)
Area Number of samples Number of non-compliant samples Number of compliant samples Percentage of samples in compliance
Atlantic 1,125 129 996 88.5
Quebec 5,272 416 4,856 92.1
Ontario 4,090 501 3,589 87.8
Western 4,137 740 3,397 82.1
National 14,624 1,786 12,838 87.8

Evaluation of feed sample compliance by feed type

Table 3A presents a summary of the number of feed samples collected and the compliance results by feed type. The majority of the 14,624 samples collected from April 1, 1989, to March 31, 2016, were complete feeds, feed supplements, and single ingredient feeds. Trace mineral salt and converter feeds were not represented. Table 2-A of Appendix I presents compliance results for feed samples by feed type for each fiscal year (April 1 to March 31).

Table 3A: Number of feed samples tested for Salmonella by feed type, from April 1, 1989, to March 31, 2018; results presented in terms of compliance (Salmonella not detected) or non-compliance (Salmonella detected)
Feed Type Number of samples Number of non-compliant samples Number of compliant samples Percentage of samples in compliance
Complete feed 7,372 557 6,815 92.4
Supplement 1,419 276 1,143 80.5
Macro-premix 332 33 299 90.1
Mineral feed 34 2 32 94.1
Micro-premix 48 7 41 85.4
Specialty product 153 7 146 95.4
Single ingredient feed 5,142 894 4,248 82.6
Others 4 0 4 100.0
Unknown 120 10 110 91.7
Total 14,624 1786 12,838 87.8

Evaluation of feed sample compliance by single ingredient type

The single ingredient category is very diverse and for this report the single ingredients have been classified in the categories shown in Table 3B.

Table 3B: Number of single ingredient feed (SIF) samples tested for Salmonella by single ingredient type, from April 1, 1989, to March 31, 2018; results presented in terms of compliance (Salmonella not detected) or non-compliance (Salmonella detected)
Single Ingredient Type Number of samples Number of non-compliant samples Number of compliant samples Percentage of samples in compliance
Grains and oilseeds Table Note 1 276 6 270 97.8
Grain by-products Table Note 2 147 4 143 97.3
Plant protein products Table Note 3 395 54 341 86.3
Animal by-products Table Note 4 587 104 483 82.3
Recycled food products Table Note 5 172 1 171 99.4
Others 16 1 15 93.8
Total 1,593 170 1,423 89.3

Evaluation of feed sample compliance by target species

Table 4 presents a summary of the number of feed samples collected and the compliance results by the target species of the feed sampled. Multiple species feeds, which are predominantly SIFs, were sampled most frequently, but large numbers of samples from specific feeds for chickens, swine, and cattle (dairy and beef) were also collected. Table 3-A in Appendix I presents compliance results for feed samples by target species for each fiscal year (April 1 to March 31).

Table 4: Number of feed samples tested for Salmonella by target species of the feed sampled, from April 1, 1989, to March 31, 2018; results presented in terms of compliance (Salmonella not detected) or non-compliance (Salmonella detected)
Target Species Number of samples Number of non-compliant samples Number of compliant samples Percentage of samples in compliance
Layer chickens 2,297 237 2,060 89.7
Broiler chickens 1,755 163 1,592 90.7
Turkey 349 32 317 90.8
Swine 2,125 249 1,876 88.3
Dairy cattle 1,558 104 1,454 93.3
Beef cattle 565 35 530 93.8
Sheep 72 3 69 95.8
Miscellaneous 487 50 437 89.7
Multiple species 5,295 903 4,392 82.9
Others 2 0 2 100.0
Unknown 119 10 109 91.6
Total 14,624 1,786 12,838 87.8

Evaluation of serotypes of Salmonella isolated from feed samples

Table 5 presents a summary of the Salmonella bacteria serotypes isolated from feed samples collected from 1989-90 to 2017-18. Salmonella bacteria were detected in 1,786 of the 14,624 feed samples collected during this period. The serotyping of these isolates was performed by the Public Health Agency of Canada (PHAC). A total of 117 serotypes were identified from 1,786 isolates (Salmonella species taxonomy and serotype names are reviewed in Appendix II), while 360 isolates were of unknown serotype and 8 isolates were found untypable. The serotype composition within the Salmonella bacteria isolated from feed was highly diverse. This is likely a reflection of the multiple sources of Salmonella contamination in feed.

Table 5: Number of Salmonella isolates by serotype detected in sampled feeds and the percentage of all Salmonella isolates represented by each serotype, from April 1, 1989, to March 31, 2018
Serotype Number of isolates % of Total Salmonella isolates represented by serotype
Senftenberg 190 10.64
Mbandaka 149 8.34
Tennessee 87 4.87
Montevideo 86 4.82
Schwarzengrund 79 4.42
Johannesburg 62 3.47
Anatum 52 2.91
Infantis 49 2.74
Agona 47 2.63
Havana 39 2.18
Livingstone 38 2.13
Orion 34 1.90
Worthington 34 1.90
Ohio 30 1.68
Cerro 28 1.57
Oranienburg 28 1.57
Cubana 26 1.46
Thompson 24 1.34
Typhimurium 20 1.12
Banana 18 1.01
California 17 0.95
Brandenburg 12 0.67
Muenster 12 0.67
Heidelberg 11 0.62
Kentucky 11 0.62
Meleagridis 11 0.62
Rissen 11 0.62
Bredeney 10 0.56
London 9 0.50
Newport 8 0.45
Java 7 0.39
Rubislaw 7 0.39
Alachua 6 0.34
Braenderup 6 0.34
Give 6 0.34
Orion var 15+ 34+ 6 0.34
Amsterdam 5 0.28
Enteritidis 5 0.28
Hadar 5 0.28
Taksony 5 0.28
Thomasville 5 0.28
Amsterdam var. 15+34+ 4 0.22
Hartford 4 0.22
Newlington 4 0.22
Uganda 4 0.22
Urbana 4 0.22
Derby 3 0.17
I:15:z10:- 3 0.17
I:Rough-O:d:1,7 3 0.17
Lexington 3 0.17
Lille 3 0.17
Minnesota 3 0.17
Putten 3 0.17
Westhampton 3 0.17
 I:ROUGH-O:b:e,n,x 2 0.11
:19:r:- 2 0.11
Abony 2 0.11
Amager 2 0.11
Anatum var 15+ 2 0.11
Arkansas 2 0.11
Bareilly 2 0.11
Ealing 2 0.11
I: rough -O:z4,z23:- 2 0.11
I:6,7:b:- 2 0.11
I:6,7:z10:- 2 0.11
I:Rough-0:z29:- 2 0.11
I:Rough-O:-:- 2 0.11
Ohio var 14+ 2 0.11
Soerenga 2 0.11
Tennessee var 14+ 2 0.11
 l:10:-:1,6 1 0.06
1:4,12:B 1 0.06
Adelaide 1 0.06
Berta 1 0.06
Binza 1 0.06
Chester 1 0.06
Gaminara 1 0.06
Haardt 1 0.06
I: :r:- 1 0.06
I:10:e,h:- 1 0.06
I:19:-:- 1 0.06
I:19:-:- 1 0.06
I:28:y:- 1 0.06
I:4,12:-:1,7 1 0.06
I:4,12:b:- 1 0.06
I:4,12:d:- 1 0.06
I:4,5,12:b:- 1 0.06
I:4,5,12:i:- 1 0.06
I:40:-:- 1 0.06
I:42:z4,z23:- 1 0.06
I:42:z4,z23:- 1 0.06
I:6,7,14:z10:- 1 0.06
I:Rough-O:m,t:- 1 0.06
I:Rough-O:r:- 1 0.06
Idikan 1 0.06
Indiana 1 0.06
l:10:-:1,5 1 0.06
l:4,12:d:- 1 0.06
Liverpool 1 0.06
Livingstone var 14+1 1 0.06
Llandoff 1 0.06
Mbandaka var14+ 1 0.06
Molade 1 0.06
Muenchen 1 0.06
Muenster var.15+34+ 1 0.06
Orion var. 15+ 1 0.06
Othmarschen 1 0.06
Ouakam 1 0.06
Pomona 1 0.06
Putten 1 0.06
Reading 1 0.06
Sandiego 1 0.06
species I:4,5,12:b:- 1 0.06
species I:8,20:z10:- 1 0.06
Tado 1 0.06
Typhimurium phagetype 170 1 0.06
Vom 1 0.06
Untypable (-:-:-:-) 8 0.45
Unknown/inconnu* 360 20.16
Total 1,786 100.00

Appendix I: Salmonella testing of feed samples by fiscal year and CFIA area

Table A-1: Number of feed samples tested for Salmonella by fiscal year (April 1 to March 31) and CFIA area, from 1989-90 to 2017-18; results presented in terms of compliance (Salmonella not detected) or non-compliance (Salmonella detected)
Fiscal Year Area Number of Samples Number of non-compliant samples Number of compliant samples Percentage of samples in compliance
1989-1990 Atlantic 98 13 85 86.7
1989-1990 Quebec 213 22 191 89.7
1989-1990 Ontario 201 38 163 81.1
1989-1990 Western 267 55 212 79.4
1989-1990 Total 779 128 651 83.6
1990-1991 Atlantic 143 19 124 86.7
1990-1991 Quebec 188 26 162 86.2
1990-1991 Ontario 262 42 220 84
1990-1991 Western 320 97 223 69.7
1990-1991 Total 913 184 729 79.9
1991-1992 Atlantic 93 18 75 80.7
1991-1992 Quebec 274 33 241 88
1991-1992 Ontario 185 39 146 78.9
1991-1992 Western 210 51 159 75.7
1991-1992 Total 762 141 621 81.5
1992-1993 Atlantic 67 11 56 83.6
1992-1993 Quebec 308 40 268 87
1992-1993 Ontario 309 65 244 79
1992-1993 Western 234 69 165 70.5
1992-1993 Total 918 185 733 79.9
1993-1994 Atlantic 46 4 42 91.3
1993-1994 Quebec 227 35 192 84.6
1993-1994 Ontario 281 58 223 79.4
1993-1994 Western 181 55 126 69.6
1993-1994 Total 735 152 583 79.3
1994-1995 Atlantic 48 4 44 91.7
1994-1995 Quebec 268 25 243 90.7
1994-1995 Ontario 255 39 216 84.7
1994-1995 Western 188 47 141 75
1994-1995 Total 759 115 644 84.9
1995-1996 Atlantic 45 9 36 80
1995-1996 Quebec 237 21 216 91.1
1995-1996 Ontario 240 18 222 92.5
1995-1996 Western 180 32 148 82.2
1995-1996 Total 702 80 622 88.6
1996-1997 Atlantic 48 8 40 83.3
1996-1997 Quebec 284 20 264 93
1996-1997 Ontario 207 16 191 92.3
1996-1997 Western 151 28 123 81.5
1996-1997 Total 690 72 618 89.6
1997-1998 Atlantic 42 4 38 90.5
1997-1998 Quebec 237 24 213 89.9
1997-1998 Ontario 134 15 119 88.8
1997-1998 Western 164 37 127 77.4
1997-1998 Total 577 80 497 86.1
1998-1999 Atlantic 39 7 32 82.1
1998-1999 Quebec 198 10 188 95
1998-1999 Ontario 195 21 174 89.2
1998-1999 Western 146 27 119 81.5
1998-1999 Total 578 65 513 88.8
1999-2000 Atlantic 29 4 25 86.2
1999-2000 Quebec 187 9 178 95.2
1999-2000 Ontario 116 24 92 79.3
1999-2000 Western 120 16 104 86.7
1999-2000 Total 452 53 399 88.3
2000-2001 Atlantic 26 2 24 92.3
2000-2001 Quebec 185 4 181 97.8
2000-2001 Ontario 93 18 75 80.6
2000-2001 Western 113 18 95 84.1
2000-2001 Total 417 42 375 89.9
2001-2002 Atlantic 28 1 27 96.4
2001-2002 Quebec 141 1 140 99.3
2001-2002 Ontario 103 14 89 86.4
2001-2002 Western 116 7 109 94.0
2001-2002 Total 388 23 365 94.1
2002-2003 Atlantic 21 1 20 95.2
2002-2003 Quebec 171 7 164 95.9
2002-2003 Ontario 94 9 85 90.4
2002-2003 Western 159 11 148 93.1
2002-2003 Total 445 28 417 93.7
2003-2004 Atlantic 37 10 27 73.0
2003-2004 Quebec 184 13 171 92.9
2003-2004 Ontario 82 5 77 93.9
2003-2004 Western 149 21 128 85.9
2003-2004 Total 452 49 403 89.2
2004-2005 Atlantic 17 3 14 82.4
2004-2005 Quebec 179 13 166 92.7
2004-2005 Ontario 93 4 89 95.7
2004-2005 Western 128 17 111 86.7
2004-2005 Total 417 37 380 91.1
2005-2006 Atlantic 11 1 10 90.9
2005-2006 Quebec 166 6 160 96.4
2005-2006 Ontario 45 3 42 93.3
2005-2006 Western 104 13 91 87.5
2005-2006 Total 326 23 303 92.9
2006-2007 Atlantic 19 3 16 84.2
2006-2007 Quebec 152 10 142 93.4
2006-2007 Ontario 86 3 83 96.5
2006-2007 Western 130 12 118 90.8
2006-2007 Total 387 28 359 92.8
2007-2008 Atlantic 22 0 22 100.0
2007-2008 Quebec 183 11 172 94.0
2007-2008 Ontario 103 13 90 87.4
2007-2008 Western 110 12 98 89.1
2007-2008 Total 418 36 382 91.4
2008-2009 Atlantic 28 1 27 96.4
2008-2009 Quebec 177 15 162 91.5
2008-2009 Ontario 120 8 112 93.3
2008-2009 Western 108 13 95 88.0
2008-2009 Total 433 37 396 91.5
2009-2010 Atlantic 24 1 23 95.8
2009-2010 Quebec 124 9 115 92.7
2009-2010 Ontario 85 2 83 97.6
2009-2010 Western 111 21 90 81.1
2009-2010 Total 344 33 311 90.4
2010-2011 Atlantic 27 1 26 96.3
2010-2011 Quebec 135 2 133 98.5
2010-2011 Ontario 97 4 93 95.9
2010-2011 Western 80 10 70 87.5
2010-2011 Total 339 17 322 95.0
2011-2012 Atlantic 32 1 31 96.9
2011-2012 Quebec 133 2 131 98.5
2011-2012 Ontario 119 3 116 97.5
2011-2012 Western 93 9 84 90.3
2011-2012 Total 377 15 362 96.0
2012-2013 Atlantic 25 0 25 100.0
2012-2013 Quebec 121 10 111 91.7
2012-2013 Ontario 121 9 112 92.6
2012-2013 Western 110 14 96 87.3
2012-2013 Total 377 33 344 91.2
2013-2014 Atlantic 26 1 25 96.2
2013-2014 Quebec 114 6 108 94.7
2013-2014 Ontario 92 9 83 90.2
2013-2014 Western 99 12 87 87.9
2013-2014 Total 331 28 303 91.5
2014-2015 Atlantic 17 1 16 94.1
2014-2015 Quebec 161 16 145 90.1
2014-2015 Ontario 85 8 77 90.6
2014-2015 Western 106 9 97 91.5
2014-2015 Total 369 34 335 90.8
2015-2016 Atlantic 19 0 19 100.0
2015-2016 Quebec 100 7 93 93.0
2015-2016 Ontario 82 2 80 97.6
2015-2016 Western 95 9 86 90.5
2015-2016 Total 296 18 278 93.9
2016-2017 Atlantic 24 0 24 100.0
2016-2017 Quebec 93 11 82 88.2
2016-2017 Ontario 107 4 103 96.3
2016-2017 Western 78 7 71 91.0
2016-2017 Total 302 22 280 92.7
2017-2018 Atlantic 24 1 23 95.8
2017-2018 Quebec 132 8 124 93.9
2017-2018 Ontario 98 8 90 91.8
2017-2018 Western 87 11 76 87.4
2017-2018 Total 341 28 313 91.8
1989-2018 Total 14,624 1,786 12,838 87.8

Salmonella testing of feed samples by fiscal year and feed type

Table 2-A: Number of samples tested and the percentage compliant samples in feed samples collected from April 1, 1989, to March 31, 2018 and analyzed by fiscal year and feed type
Fiscal Year Feed Type Number of Samples Number of Non-compliant Samples Number of Compliant Samples Percentage of samples in compliance
1989-1990 Complete feed 349 28 321 92
1989-1990 Supplement 135 40 95 70.4
1989-1990 Macro-premix 20 4 16 80
1989-1990 Mineral feed 2 0 2 100
1989-1990 Specialty product 5 0 5 100
1989-1990 Single ingredient feed 268 56 212 79.1
1989-1990 Total 779 128 651 83.6
1990-1991 Complete feed 343 30 313 91.3
1990-1991 Supplement 171 51 120 70.2
1990-1991 Macro-premix 23 1 22 95.7
1990-1991 Mineral feed 4 1 3 75
1990-1991 Specialty product 7 1 6 85.7
1990-1991 Single ingredient feed 365 100 265 72.6
1990-1991 Total 913 184 729 79.9
1991-1992 Complete feed 331 33 298 90
1991-1992 Supplement 86 16 70 81.4
1991-1992 Macro-premix 34 8 26 76.5
1991-1992 Specialty product 5 0 5 100
1991-1992 Single ingredient feed 306 84 222 72.6
1991-1992 Total 762 141 621 81.5
1992-1993 Complete feed 473 64 409 86.5
1992-1993 Supplement 99 33 66 66.7
1992-1993 Macro-premix 26 4 22 84.6
1992-1993 Micro-premix 2 2 0 0
1992-1993 Specialty product 2 1 1 50
1992-1993 Single ingredient feed 316 81 235 74.4
1992-1993 Total 918 185 733 79.9
1993-1994 Complete feed 380 60 320 84.2
1993-1994 Supplement 78 22 56 71.8
1993-1994 Macro-premix 20 3 17 85
1993-1994 Mineral feed 1 0 1 100
1993-1994 Specialty product 4 1 3 75
1993-1994 Single ingredient feed 252 66 186 73.8
1993-1994 Total 735 152 583 79.3
1994-1995 Complete feed 368 29 339 92.1
1994-1995 Supplement 88 19 69 78.4
1994-1995 Macro-premix 33 3 30 90.9
1994-1995 Micro-premix 1 0 1 100
1994-1995 Specialty product 2 0 2 100
1994-1995 Single ingredient feed 267 64 203 76
1994-1995 Total 759 115 644 84.9
1995-1996 Complete feed 365 22 343 94
1995-1996 Supplement 98 20 78 79.6
1995-1996 Macro-premix 21 3 18 85.7
1995-1996 Mineral feed 1 0 1 100
1995-1996 Micro-premix 4 3 1 25
1995-1996 Specialty product 4 0 4 100
1995-1996 Single ingredient feed 209 32 177 84.7
1995-1996 Total 702 80 622 88.6
1996-1997 Complete feed 385 27 358 93
1996-1997 Supplement 71 12 59 83.1
1996-1997 Macro-premix 21 1 20 95.2
1996-1997 Micro-premix 2 0 2 100
1996-1997 Specialty product 10 0 10 100
1996-1997 Single ingredient feed 201 32 169 84.1
1996 -1997 Total 690 72 618 89.6
1997-1998 Complete feed 309 24 285 92.2
1997-1998 Supplement 55 11 44 80
1997-1998 Macro-premix 16 0 16 100
1997-1998 Specialty product 5 0 5 100
1997-1998 Single ingredient feed 192 45 147 76.6
1997-1998 Total 577 80 497 86.1
1998-1999 Complete feed 352 26 326 92.6
1998-1999 Supplement 39 7 32 82.1
1998-1999 Macro-premix 11 2 9 81.8
1998-1999 Micro-premix 1 0 1 100
1998-1999 Specialty product 2 2 0 0
1998-1999 Single ingredient feed 173 28 145 83.8
1998-1999 Total 578 65 513 88.8
1999-2000 Complete feed 230 10 220 95.7
1999-2000 Supplement 49 9 40 81.6
1999-2000 Macro-premix 4 0 4 100
1999-2000 Micro-premix 1 0 1 100
1999-2000 Specialty product 12 0 12 100
1999-2000 Single ingredient feed 156 34 122 78.2
1999-2000 Total 452 53 399 88.3
2000-2001 Complete feed 221 13 208 94.1
2000-2001 Supplement 32 6 26 81.3
2000-2001 Macro-premix 4 0 4 100.0
2000-2001 Mineral feed 1 1 0 0.0
2000-2001 Micro-premix 3 1 2 66.7
2000-2001 Specialty product 3 0 3 100.0
2000-2001 Others 2 0 2 100.0
2000-2001 Unknown 5 0 5 100.0
2000-2001 Single ingredient feed 146 21 125 85.6
2000-2001 Total 417 42 375 89.9
2001-2002 Complete feed 225 10 215 95.6
2001-2002 Supplement 24 1 23 95.8
2001-2002 Macro-premix 6 0 6 100.0
2001-2002 Micro-premix 4 0 4 100.0
2001-2002 Specialty product 6 0 6 100.0
2001-2002 Single ingredient feed 116 12 104 89.7
2001-2002 Unknown 7 0 7 100.0
2001-2002 Total 388 23 365 94.1
2002-2003 Complete feed 281 12 269 95.7
2002-2003 Supplement 36 5 31 86.1
2002-2003 Macro-premix 1 0 1 100.0
2002-2003 Micro-premix 1 0 1 100.0
2002-2003 Mineral feed 2 0 2 100.0
2002-2003 Specialty product 4 0 4 100.0
2002-2003 Single ingredient feed 107 11 96 89.7
2002-2003 Unknown 13 0 13 100.0
2002-2003 Total 445 28 417 93.7
2003-2004 Complete feed 269 22 247 91.8
2003-2004 Supplement 20 2 18 90.0
2003-2004 Macro-premix 6 1 5 83.3
2003-2004 Specialty product 3 0 3 100.0
2003-2004 Single ingredient feed 134 20 114 85.1
2003-2004 Converter feed 1 0 1 100.0
2003-2004 Unknown 19 4 15 78.9
2003-2004 Total 452 49 403 89.2
2004-2005 Complete feed 255 23 232 91.0
2004-2005 Supplement 27 2 25 92.6
2004-2005 Macro-premix 3 0 3 100.0
2004-2005 Mineral feed 1 0 1 100.0
2004-2005 Micro-premix 1 0 1 100.0
2004-2005 Specialty product 3 0 3 100.0
2004-2005 Single ingredient feed 111 11 100 90.1
2004-2005 Unknown 16 1 15 93.8
2004-2005 Total 417 37 380 91.1
2005-2006 Complete feed 170 9 161 94.7
2005-2006 Supplement 27 1 26 96.3
2005-2006 Macro-premix 8 0 8 100.0
2005-2006 Micro-premix 1 0 1 100.0
2005-2006 Specialty product 2 0 2 100.0
2005-2006 Single ingredient feed 101 13 88 87.1
2005-2006 Unknown 17 0 17 100.0
2005-2006 Total 326 23 303 92.9
2006-2007 Complete feed 206 11 195 94.7
2006-2007 Supplement 20 1 19 95.0
2006-2007 Macro-premix 4 1 3 75.0
2006-2007 Mineral feed 2 0 2 100.0
2006-2007 Micro-premix 1 0 1 100.0
2006-2007 Specialty product 3 0 3 100.0
2006-2007 Single ingredient feed 129 14 115 89.1
2006-2007 Unknown 22 1 21 95.5
2006-2007 Total 387 28 359 92.8
2007-2008 Complete feed 201 13 188 93.5
2007-2008 Supplement 33 2 31 93.9
2007-2008 Macro-premix 3 0 3 100.0
2007-2008 Specialty product 4 0 4 100.0
2007-2008 Single ingredient feed 162 17 145 89.5
2007-2008 Unknown 15 4 11 73.3
2007-2008 Total 418 36 382 91.4
2008-2009 Complete feed 233 11 222 95.3
2008-2009 Supplement 26 1 25 96.2
2008-2009 Macro-premix 7 1 6 85.7
2008-2009 Mineral feed 2 0 2 100.0
2008-2009 Micro-premix 1 0 1 100.0
2008-2009 Specialty product 8 0 8 100.0
2008-2009 Single ingredient feed 154 24 130 84.4
2008-2009 Unknown 2 0 2 100.0
2008-2009 Total 433 37 396 91.5
2009-2010 Complete feed 143 14 129 90.2
2009-2010 Supplement 17 2 15 88.2
2009-2010 Macro-premix 10 1 9 90.0
2009-2010 Mineral feed 2 0 2 100.0
2009-2010 Micro-premix 2 0 2 100.0
2009-2010 Specialty product 9 0 9 100.0
2009-2010 Single ingredient feed 161 16 145 90.1
2009-2010 Total 344 33 311 90.4
2010-2011 Complete feed 168 5 163 97.0
2010-2011 Supplement 18 1 17 94.4
2010-2011 Macro-premix 4 0 4 100.0
2010-2011 Mineral feed 3 0 3 100.0
2010-2011 Micro-premix 5 0 5 100.0
2010-2011 Specialty product 8 0 8 100.0
2010-2011 Single ingredient feed 133 11 122 91.7
2010-2011 Total 339 17 322 95.0
2011-2012 Complete feed 176 6 170 96.6
2011-2012 Supplement 25 1 24 96.0
2011-2012 Macro-premix 11 0 11 100.0
2011-2012 Mineral feed 1 0 1 100.0
2011-2012 Micro-premix 2 0 2 100.0
2011-2012 Specialty product 5 0 5 100.0
2011-2012 Single ingredient feed 154 8 146 94.8
2011-2012 Unknown 3 0 3 100.0
2011-2012 Total 377 15 362 96.0
2012-2013 Complete feed 185 10 175 94.6
2012-2013 Supplement 20 1 19 95.0
2012-2013 Macro-premix 9 0 9 100.0
2012-2013 Mineral feed 1 0 1 100.0
2012-2013 Micro-premix 6 0 6 100.0
2012-2013 Mineral feed trace 1 0 1 100.0
2012-2013 Specialty product 8 1 7 87.5
2012-2013 Single ingredient feed 146 21 125 85.6
2012-2013 Unknown 1 0 1 100.0
2012-2013 Total 377 33 344 91.2
2013-2014 Complete feed 127 7 120 94.5
2013-2014 Supplement 28 3 25 89.3
2013-2014 Macro-premix 7 0 7 100.0
2013-2014 Mineral feed 2 0 2 100.0
2013-2014 Micro-premix 3 1 2 66.7
2013-2014 Specialty product 5 0 5 100.0
2013-2014 Single ingredient feed 159 17 142 89.3
2013-2014 Total 331 28 303 91.5
2014-2015 Complete feed 157 8 149 94.9
2014-2015 Supplement 25 3 22 88.0
2014-2015 Macro-premix 6 0 6 100.0
2014-2015 Mineral feed 2 0 2 100.0
2014-2015 Micro-premix 3 0 3 100.0
2014-2015 Specialty product 5 0 5 100.0
2014-2015 Single ingredient feed 171 23 148 86.5
2014-2015 Total 369 34 335 90.8
2015-2016 Complete feed 145 8 137 94.5
2015-2016 Supplement 21 0 21 100.0
2015-2016 Macro-premix 7 0 7 100.0
2015-2016 Mineral feed 5 0 5 100.0
2015-2016 Micro-premix 1 0 1 100.0
2015-2016 Specialty product 7 0 7 100.0
2015-2016 Single ingredient feed 110 10 100 90.9
2015-2016 Total 296 18 278 93.9
2016-2017 Complete feed 153 12 141 92.2
2016-2017 Supplement 21 1 20 95.2
2016-2017 Macro-premix 3 0 3 100.0
2016-2017 Micro-premix 1 0 1 100.0
2016-2017 Specialty product 7 1 6 85.7
2016-2017 Single ingredient feed 117 8 109 93.2
2016-2017 Total 302 22 280 92.7
2017-2018 Complete feed 172 10 162 94.2
2017-2018 Supplement 30 3 27 90.0
2017-2018 Macro-premix 4 0 4 100.0
2017-2018 Mineral feed 2 0 2 100.0
2017-2018 Micro-premix 2 0 2 100.0
2017-2018 Specialty product 5 0 5 100.0
2017-2018 Single ingredient feed 126 15 111 88.1
2017-2018 Total 341 28 313 91.8
1989-2018 Total 14,624 1,786 12,838 87.8

Salmonella testing of feed samples by fiscal year and target species

Table 3-A: Number of samples tested and the percentage of compliant samples in feed samples collected from April 1, 1989, to March 31, 2018 and analyzed by fiscal year and target species
Fiscal Year Target Species Number of Samples Number of Non-compliant Samples Number of Compliant Samples Percentage of samples in compliance
1989-1990 Layer chickens 132 21 111 84.1
1989-1990 Broiler chickens 110 12 98 89.1
1989-1990 Turkey 33 2 31 93.9
1989-1990 Swine 123 29 94 76.4
1989-1990 Dairy cattle 89 8 81 91
1989-1990 Beef cattle 6 0 6 100
1989-1990 Sheep 1 0 1 100
1989-1990 Miscellaneous 12 0 12 100
1989-1990 Multiple species 273 56 217 79.5
1989-1990 Total 779 128 651 83.6
1990-1991 Layer chickens 161 30 131 81.4
1990-1991 Broiler chickens 83 15 68 81.9
1990-1991 Turkey 27 2 25 92.6
1990-1991 Swine 135 30 105 77.8
1990-1991 Dairy cattle 92 5 87 94.6
1990-1991 Beef cattle 25 2 23 92
1990-1991 Sheep 2 0 2 100
1990-1991 Miscellaneous 15 0 15 100
1990-1991 Multiple species 373 100 273 73.2
1991-1991 Total 913 184 729 79.9
1991-1992 Layer chickens 123 23 100 81.3
1991-1992 Broiler chickens 93 12 81 87.1
1991-1992 Turkey 25 2 23 92
1991-1992 Swine 104 15 89 85.6
1991-1992 Dairy cattle 80 4 76 95
1991-1992 Beef cattle 14 0 14 100
1991-1992 Sheep 2 0 2 100
1991-1992 Miscellaneous 11 1 10 90.9
1991-1992 Multiple species 310 84 226 72.9
1991-1992 Total 762 141 621 81.5
1992-1993 Layer chickens 162 32 130 80.3
1992-1993 Broiler chickens 138 14 124 89.9
1992-1993 Turkey 28 4 24 85.7
1992-1993 Swine 142 29 113 79.6
1992-1993 Dairy cattle 76 12 64 84.2
1992-1993 Beef cattle 23 3 20 87
1992-1993 Sheep 2 0 2 100
1992-1993 Miscellaneous 29 9 20 69
1992-1993 Multiple species 318 82 236 74.2
1992-1993 Total 918 185 733 79.9
1993-1994 Layer chickens 114 17 97 85.1
1993-1994 Broiler chickens 102 18 84 82.4
1993-1994 Turkey 32 10 22 68.8
1993-1994 Swine 129 25 104 80.6
1993-1994 Dairy cattle 73 9 64 87.7
1993-1994 Beef cattle 15 3 12 80
1993-1994 Miscellaneous 16 3 13 81.3
1993-1994 Multiple species 254 67 187 73.6
1993-1994 Total 735 152 583 79.3
1994-1995 Layer chickens 132 12 120 90.9
1994-1995 Broiler chickens 116 9 107 92.2
1994-1995 Turkey 22 0 22 100
1994-1995 Swine 117 17 100 85.5
1994-1995 Dairy cattle 66 6 60 90.9
1994-1995 Beef cattle 21 6 15 71.4
1994-1995 Sheep 6 0 6 100
1994-1995 Miscellaneous 10 1

9

90
1994-1995 Multiple species 269 64 205 76.2
1994-1995 Total 759 115 644 84.9
1995-1996 Layer chickens 125 7 118 94.4
1995-1996 Broiler chickens 106 12 94 88.7
1995-1996 Turkey 31 1 30 96.8
1995-1996 Swine 109 20 89 81.7
1995-1996 Dairy cattle 73 5 68 93.2
1995-1996 Beef cattle 30 0 30 100
1995-1996 Miscellaneous 16 3 13 81.3
1995-1996 Multiple species 212 32 180 84.9
1995-1996 Total 702 80 622 88.6
1996-1997 Layer chickens 124 10 114 91.9
1996-1997 Broiler chickens 115 13 102 88.7
1996-1997 Turkey 19 0 19 100
1996-1997 Swine 87 10 77 88.5
1996-1997 Dairy cattle 87 2 85 97.7
1996-1997 Beef cattle 26 2 24 92.3
1996-1997 Sheep 6 2 4 66.7
1996-1997 Miscellaneous 17 0 17 100
1996-1997 Multiple species 209 33 176 84.2
1996-1997 Total 690 72 618 89.6
1997-1998 Layer chickens 89 10 79 88.8
1997-1998 Broiler chickens 86 6 80 93
1997-1998 Turkey 12 1 11 91.7
1997-1998 Swine 80 8 72 90
1997-1998 Dairy cattle 80 7 73 91.3
1997-1998 Beef cattle 13 0 13 100
1997-1998 Sheep 2 0 2 100
1997-1998 Miscellaneous 18 3 15 83.3
1997-1998 Multiple species 197 45 152 77.2
1997-1998 Total 577 80 497 86.1
1998-1999 Layer chickens 101 11 90 89.1
1998-1999 Broiler chickens 94 6 88 93.6
1998-1999 Turkey 8 3 5 62.5
1998-1999 Swine 75 5 70 93.3
1998-1999 Dairy cattle 86 5 81 94.2
1998-1999 Beef cattle 18 3 15 83.3
1998-1999 Sheep 1 0 1 100
1998-1999 Miscellaneous 20 3 17 85
1998-1999 Multiple species 175 29 146 83.4
1998-1999 Total 578 65 513 88.8
1999-2000 Layer chickens 75 4 71 94.7
1999-2000 Broiler chickens 56 1 55 98.2
1999-2000 Turkey 4 0 4 100
1999-2000 Swine 56 6 50 89.3
1999-2000 Dairy cattle 57 5 52 91.2
1999-2000 Beef cattle 18 2 16 88.9
1999-2000 Sheep 1 0 1 100
1999-2000 Miscellaneous 17 2 15 88.2
1999-2000 Multiple species 168 33 135 80.4
1999-2000 Total 452 53 399 88.3
2000-2001 Layer chickens 65 7 58 89.2
2000-2001 Broiler chickens 51 3 48 94.1
2000-2001 Turkey 12 0 12 100.0
2000-2001 Swine 62 7 55 88.7
2000-2001 Dairy cattle 36 1 35 97.2
2000-2001 Beef cattle 14 0 14 100.0
2000-2001 Sheep 6 0 6 100.0
2000-2001 Miscellaneous 14 3 11 78.6
2000-2001 Multiple species 150 21 129 86.0
2000-2001 Others 2 0 2 100.0
2000-2001 Unknown 5 0 5 100.0
2000-2001 Total 417 42 375 89.9
2001-2002 Layer chickens 69 5 64 92.8
2001-2002 Broiler chickens 42 1 41 97.6
2001-2002 Turkey 7 0 7 100.0
2001-2002 Swine 62 2 60 96.8
2001-2002 Dairy cattle 40 0 40 100.0
2001-2002 Beef cattle 18 0 18 100.0
2001-2002 Sheep 3 0 3 100.0
2001-2002 Miscellaneous 19 2 17 89.5
2001-2002 Multiple species 122 13 109 89.3
2001-2002 Unknown 6 0 6 100.0
2001-2002 Total 388 23 365 94.1
2002-2003 Layer chickens 88 3 85 96.6
2002-2003 Broiler chickens 57 4 53 93.0
2002-2003 Turkey 10 2 8 80.0
2002-2003 Swine 71 5 66 93.0
2002-2003 Dairy cattle 49 2 47 95.9
2002-2003 Beef cattle 23 0 23 100.0
2002-2003 Sheep 1 1 0 0.0
2002-2003 Miscellaneous 14 0 14 100.0
2002-2003 Multiple species 119 11 108 90.8
2002-2003 Unknown 13 0 13 100.0
2002-2003 Total 445 28 417 93.7
2003-2004 Layer chickens 77 8 69 89.6
2003-2004 Broiler chickens 62 7 55 88.7
2003-2004 Turkey 7 0 7 100.0
2003-2004 Swine 71 3 68 95.8
2003-2004 Dairy cattle 34 2 32 94.1
2003-2004 Beef cattle 25 0 25 100.0
2003-2004 Sheep 2 0 2 100.0
2003-2004 Miscellaneous 17 4 13 76.5
2003-2004 Multiple species 138 21 117 84.8
2003-2004 Unknown 19 4 15 78.9
2003-2004 Total 452 49 403 89.2
2004-2005 Layer chickens 87 8 79 90.8
2004-2005 Broiler chickens 44 4 40 90.9
2004-2005 Turkey 8 1 7 87.5
2004-2005 Swine 52 2 50 96.2
2004-2005 Dairy cattle 46 5 41 89.1
2004-2005 Beef cattle 23 4 19 82.6
2004-2005 Sheep 2 0 2 100.0
2004-2005 Miscellaneous 19 1 18 94.7
2004-2005 Multiple species 120 11 109 90.8
2004-2005 Unknown 16 1 15 93.8
2004-2005 Total 417 37 380 91.1
2005-2006 Layer chickens 55 1 54 98.2
2005-2006 Broiler chickens 42 5 37 88.1
2005-2006 Turkey 6 0 6 100.0
2005-2006 Swine 42 2 40 95.2
2005-2006 Dairy cattle 41 0 41 100.0
2005-2006 Beef cattle 10 0 10 100.0
2005-2006 Sheep 2 0 2 100.0
2005-2006 Miscellaneous 10 2 8 80.0
2005-2006 Multiple species 101 13 88 87.1
2005-2006 Unknown 17 0 17 100.0
2005-2006 Total 326 23 303 92.9
2006-2007 Layer chickens 38 4 34 89.5
2006-2007 Broiler chickens 32 2 30 93.8
2006-2007 Turkey 5 0 5 100.0
2006-2007 Swine 66 2 64 97.0
2006-2007 Dairy cattle 45 2 43 95.6
2006-2007 Beef cattle 22 1 21 95.5
2006-2007 Sheep 6 0 6 100.0
2006-2007 Miscellaneous 16 1 15 93.8
2006-2007 Multiple species 135 15 120 88.9
2006-2007 Unknown 22 1 21 95.5
2006-2007 Total 387 28 359 92.8
2007-2008 Layer chickens 38 2 36 94.7
2007-2008 Broiler chickens 29 2 27 93.1
2007-2008 Turkey 6 0 6 100.0
2007-2008 Swine 75 5 70 93.3
2007-2008 Dairy cattle 44 3 41 93.2
2007-2008 Beef cattle 21 1 20 95.2
2007-2008 Miscellaneous 23 2 21 91.3
2007-2008 Multiple species 167 17 150 89.8
2007-2008 Unknown 15 4 11 73.3
2007-2008 Total 418 36 382 91.4
2008-2009 Layer chickens 53 2 51 96.2
2008-2009 Broiler chickens 41 2 39 95.1
2008-2009 Turkey 11 1 10 90.9
2008-2009 Swine 56 3 53 94.6
2008-2009 Dairy cattle 43 2 41 95.3
2008-2009 Beef cattle 28 1 27 96.4
2008-2009 Sheep 4 0 4 100.0
2008-2009 Miscellaneous 30 2 28 93.3
2008-2009 Multiple species 165 24 141 85.5
2008-2009 Unknown 2 0 2 100.0
2008-2009 Total 433 37 396 91.5
2009-2010 Layer chickens 34 5 29 85.3
2009-2010 Broiler chickens 23 2 21 91.3
2009-2010 Turkey 2 0 2 100.0
2009-2010 Swine 45 6 39 86.7
2009-2010 Dairy cattle 29 2 27 93.1
2009-2010 Beef cattle 29 2 27 93.1
2009-2010 Sheep 2 0 2 100.0
2009-2010 Miscellaneous 24 0 24 100.0
2009-2010 Multiple species 156 16 140 89.7
2009-2010 Total 344 33 311 90.4
2010-2011 Layer chickens 44 1 43 97.7
2010-2011 Broiler chickens 33 1 32 97.0
2010-2011 Turkey 2 0 2 100.0
2010-2011 Swine 42 1 41 97.6
2010-2011 Dairy cattle 35 1 34 97.1
2010-2011 Beef cattle 23 0 23 100.0
2010-2011 Sheep 3 0 3 100.0
2010-2011 Miscellaneous 23 2 21 91.3
2010-2011 Multiple species 134 11 123 91.8
2010-2011 Total 339 17 322 95.0
2011-2012 Layer chickens 47 0 47 100.0
2011-2012 Broiler chickens 31 0 31 100.0
2011-2012 Turkey 1 0 1 100.0
2011-2012 Swine 51 2 49 96.1
2011-2012 Dairy cattle 44 1 43 97.7
2011-2012 Beef cattle 19 2 17 89.5
2011-2012 Sheep 3 0 3 100.0
2011-2012 Miscellaneous 22 2 20 90.9
2011-2012 Multiple species 156 8 148 94.9
2011-2012 Unknown 3 0 3 100.0
2011-2012 Total 377 15 362 96.0
2012-2013 Layer chickens 56 3 53 94.6
2012-2013 Broiler chickens 35 4 31 88.6
2012-2013 Turkey 5 0 5 100.0
2012-2013 Swine 48 1 47 97.9
2012-2013 Dairy cattle 37 0 37 100.0
2012-2013 Beef cattle 21 1 20 95.2
2012-2013 Miscellaneous 18 2 16 88.9
2012-2013 Multiple species 156 22 134 85.9
2012-2013 Unknown 1 0 1 100.0
2012-2013 Total 377 33 344 91.2
2013-2014 Layer chickens 31 1 30 96.8
2013-2014 Broiler chickens 27 1 26 96.3
2013-2014 Turkey 3 1 2 66.7
2013-2014 Swine 44 1 43 97.7
2013-2014 Dairy cattle 33 3 30 90.9
2013-2014 Beef cattle 12 2 10 83.3
2013-2014 Sheep 3 0 3 100.0
2013-2014 Miscellaneous 13 1 12 92.3
2013-2014 Multiple species 165 18 147 89.1
2013-2014 Total 331 28 303 91.5
2014-2015 Layer chickens 43 2 41 95.3
2014-2015 Broiler chickens 33 0 33 100.0
2014-2015 Turkey 10 1 9 90.0
2014-2015 Swine 43 5 38 88.4
2014-2015 Dairy cattle 36 3 33 91.7
2014-2015 Beef cattle 11 0 11 100.0
2014-2015 Sheep 1 0 1 100.0
2014-2015 Miscellaneous 11 0 11 100.0
2014-2015 Multiple species 181 23 158 87.3
2014-2015 Total 369 34 335 90.8
2015-2016 Layer chickens 41 3 38 92.7
2015-2016 Broiler chickens 26 1 25 96.2
2015-2016 Turkey 4 0 4 100.0
2015-2016 Swine 37 3 34 91.9
2015-2016 Dairy cattle 33 1 32 97.0
2015-2016 Beef cattle 27 0 27 100.0
2015-2016 Sheep 5 0 5 100.0
2015-2016 Miscellaneous 13 0 13 100.0
2015-2016 Multiple species 110 10 100 90.9
2015-2016 Total 296 18 278 93.9
2016-2017 Layer chickens 44 3 41 93.2
2016-2017 Broiler chickens 25 4 21 84.0
2016-2017 Turkey 5 0 5 100.0
2016-2017 Swine 47 2 45 95.7
2016-2017 Dairy cattle 33 4 29 87.9
2016-2017 Beef cattle 16 0 16 100.0
2016-2017 Sheep 2 0 2 100.0
2016-2017 Miscellaneous 8 0 8 100.0
2016-2017 Multiple species 122 9 113 92.6
2016-2017 Total 302 22 280 92.7
2017-2018 Layer chickens 49 2 47 95.9
2017-2018 Broiler chickens 23 2 21 91.3
2017-2018 Turkey 4 1 3 75.0
2017-2018 Swine 54 3 51 94.4
2017-2018 Dairy cattle 41 4 37 90.2
2017-2018 Beef cattle 14 0 14 100.0
2017-2018 Sheep 4 0 4 100.0
2017-2018 Miscellaneous 12 1 11 91.7
2017-2018 Multiple species 140 15 125 89.3
2017-2018 Total 341 28 313 91.8
1989-2018 Total 14,624 1,786 12,838 87.8

Appendix II: Review of Salmonella Taxonomy and Serotypes

Species and subspecies

The genus Salmonella currently contains two species; bongori and enterica. These species were determined on the basis of genetic relatedness, as determined by DNA hybridization experiments. Salmonella enterica is further divided into six subspecies that are designated by names and by Roman numerals: I enterica, II salamae, IIIarizonae, IIIdiarizonae, IV houtenae, and VI indica. These subspecies are differentiated by their biochemical reactions. Salmonella strains from all Salmonella subspecies can be found in cold-blooded animals but only strains from Salmonella enterica subspecies enterica (I) are found in warm-blooded animals. Salmonella subspecies I enterica is therefore of greatest interest to human and animal health.

Serotypes (Serovars)

Serotyping is a serological procedure based on the Kauffmann-White scheme which classifies strains of microorganisms into different groups based on their antigenic composition. The Kauffmann-White scheme is maintained by the World Health Organization at the Institut Pasteur in Paris, and strain serotyping is performed only at specialized serotyping laboratories.

Serotyping or antigenic classification of Salmonella is based on antibody reaction with 2 types of surface antigens: somatic O antigens and flagellar H antigens (phase 1 and phase 2). O antigens are polysaccharides present on the outer membrane of gram negative bacteria. H antigens are proteins present on the bacterial flagella. Salmonella serotypes may express either one type of H antigen (monophasic), or two types of H antigen (diphasic).

A Salmonella serotype is represented by an antigenic formula which is determined by a unique combination of reactions of cell surface antigens (immunologic characterization). For example, the antigenic formula for Salmonella enterica subspecies enterica serotype Typhimurium is 1,4,[5],12:i:1,2 where "1" indicates the subspecies, "4,[5],12" indicates the reaction to O-antigen antisera, "i" indicates the reaction to Phase 1 antisera of the H-antigen, and "1,2" indicates the reaction to Phase 2 antisera of the H-antigen.

The serotype name usually refers to the geographic location where the specific Salmonella strain was first isolated, although older names sometimes indicated the animal species from which it was isolated or the clinical syndrome that it caused. To emphasize that these serotype names do not represent separate species, the serotype name is not italicized and the first letter is capitalized (e.g. Salmonella enterica subspecies enterica serovar Typhimurium). For convenience, this designation is commonly shortened to include only the genus and serotype name (e.g., Salmonella Typhimurium or S. Typhimurium).

Within the Salmonella enterica species, there are over 2,500 Salmonella serotypes of which approximately 60% belong to subspecies I (enterica, found in warm-blooded animals) and these account for about 99% of human infections.

List of references

Brenner, F. W., Villar, R. G., Angulo, F. J., Tauxe, R., and Swaminathan, B., 2000. Salmonella nomenclature. J Clin Microbiol 38:2465-7.

Grimont, P. A. D., and Weill, F. X., 2007. Antigenic Formulae of the Salmonella Serovars. 9th Edition. WHO Collaborating Centre for Reference and Research on Salmonella, Paris.

Ryan, M., O'Dwyer, J., and Adley, C. C., 2017. Evaluation of the Complex Nomenclature of the Clinically and Veterinary Significant Pathogen Salmonella. BioMed Research International, vol. 2017, Article ID 3782182, 6 pages.

Tindall, B. J., Grimont, P. A., Garrity, G. M., and Euzeby, J. P., 2005. Nomenclature and taxonomy of the genus Salmonella. Int J Syst Evol Microbiol 55:521

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