Cleaning and disinfection of transport crates for poultry - comparison of four treatments at slaughter plant.

Transport crates for poultry can contribute to the spread of pathogens, with those of public health interest, for example, Campylobacter, being of particular importance. A strict cleaning procedure and use of an effective disinfection method for transport equipment are thus important to avoid introduction of Campylobacter to chicken and poultry farms, particularly during flock thinning. This study evaluated the efficacy of the disinfection procedure currently in use at one of the largest slaughter plants in Sweden and compared the effects with those of other disinfection methods. The evaluation was based on treatment ability to reduce the presence and amount of indicator bacteria belonging to the family Enterobacteriaceae and total aerobic bacteria. In 4 trials, sodium hypochlorite, peracetic acid, and drying with hot air, with or without sodium hypochlorite for final disinfection, were compared. The analysis was based on 40 cotton swab samples taken in each treatment, 20 after the soaking stage and 20 after the final disinfection step. The results showed that use of a chemical disinfectant in combination with drying with hot air (dehumidifier) was the most effective treatment, with an average reduction of 3.4 log for total aerobic bacteria and 3.8 log for Enterobacteriaceae. Since all crates treated with hot air were dry, transport conditions for the birds also improved, particularly in cold weather. A disadvantage is that this treatment is energy-consuming and would require substantial technical changes to the current cleaning process, increasing operating costs at the slaughter plant. However, considering the contribution of improved crate cleaning to overall hygiene control within the poultry supply chain and the beneficial effect on animal welfare, the costs may be justified.

Occurrence of Campylobacter spp. in Swedish calves, common sequence types and antibiotic resistance patterns.

AIMS: Cattle are the second most important cause of human campylobacteriosis, after poultry, but there are knowledge gaps regarding Campylobacter in cattle. This study examined the occurrence of Campylobacter, the species present, sequence types and antibiotic resistance in Swedish cattle. METHODS AND RESULTS: Faeces samples collected from 154 calves on seven Swedish farms, and 69 follow-up samples from a second collection occasion, were analysed. Campylobacter were isolated from 77% of calves at the first sampling, with Campylobacter jejuni as the most frequently isolated species. Animals kept on deep straw bedding were less likely to be colonized with Campylobacter. Whole-genome sequencing of 90 C. jejuni samples resulted in 11 sequence types, among which ST-19 and ST-21 were most frequent. Antimicrobial resistance analyses showed that 46% of 142 isolates analysed were resistant to quinolones, while all isolates belonging to ST-19, ST-22 and ST-441 were resistant to ciprofloxacin and nalidixic acid. CONCLUSIONS: Campylobacter jejuni was the species most frequently isolated in calves and a strong association was found between sequence type and antimicrobial resistance pattern. SIGNIFICANCE AND IMPACT OF THE STUDY: The high proportion of calves with quinolone-resistant Campylobacter jejuni should be considered in a One Health perspective.

Serological study of Leptospira interrogans serovar Copenhageni and L. borgpetersenii serovars Tarassovi and Ballum in beef cattle, sheep and deer in New Zealand.

AIMS: To estimate animal-level seroprevalence of Leptospira interrogans serovar Copenhageni and L. borgpetersenii serovars Ballum and Tarassovi, in beef cattle, sheep and deer on New Zealand farms, and herd/flock-level seroprevalence of any serovar when existing same-sera data for serovars Hardjobovis and Pomona were included, and to determine associations between risk factors and animal-level seroprevalence. METHODS: Banked sera from sheep (n = 82), beef (n = 54) and deer (n = 62) herds/flocks (n = 3,878 animals) from seven regions were analysed using the microscopic agglutination test. Titres of ≥48 were designated positive. Herds/flocks were considered positive if either ≥1, ≥2 or ≥3 animals were positive. Existing same-sera data for serovars Hardjobovis and Pomona were included to establish farm-level any-serovar seropositivity. Factors associated with serological status were analysed using generalised estimating equations. RESULTS: Animal-level seroprevalence for serovars Ballum, Copenhageni, and Tarassovi, respectively, was 13.7 (95% CI = 11.7-16.0)%, 12.6 (95% CI = 10.6-14.7)% and 18.0 (95% CI = 15.7-20.5)% for beef cattle, 10.5 (95% CI = 9.0-12.1)%, 16.7 (95% CI = 14.9-18.6)% and 14.0 (95% CI = 12.4-15.8)% for sheep and 6.6 (95% CI = 5.3-8.2)%, 15.5 (95% CI = 13.5-17.7)% and 3.6 (95% CI = 2.7-4.8)% for deer, respectively. Herd/flock-level seroprevalence for Ballum was 86.6, 52.4 and 39.0% for sheep, 85.2, 52.7 and 33.3% for beef cattle and 50.8, 27.9 and 21.3% for deer at definitions ≥1, ≥2 and ≥3 seropositive animals per species, respectively. For Copenhageni, corresponding data were 95.1, 73.2 and 56.1% for sheep, 68.5, 48.2 and 29.6% for beef cattle and 73.8, 57.4 and 41.0% for deer, and for Tarassovi, 80.5, 59.7 and 45.1% for sheep, 83.3, 68.5 and 61.1% for beef cattle, and 42.6, 16.4 and 4.9% for deer. Seropositivity to all serovars was observed from all regions, with some differences in seroprevalence observed between species and regions, but not between islands. Combining with Hardjobovis and Pomona data, herd/flock-level seropositivity for all animal species and all five Leptospira serovars was 100% at definition ≥1 animal positive, and 97.5 and 96.3% for sheep flocks, 87.8 and 97.8% for beef cattle herds, and 89.3 and 75% for deer herds at ≥2 and ≥3 animals positive, respectively. CONCLUSIONS: Seropositivity to serovars Ballum, Copenhageni and Tarassovi is common in sheep, beef cattle and deer New Zealand and most, or all farms have ≥1 livestock species seropositive to ≥1 serovar. CLINICAL RELEVANCE: Serovars Ballum, Tarassovi and Copenhageni should be considered when clinical or subclinical signs of leptospirosis are observed in sheep, beef cattle or deer. Livestock sector workers are potentially at risk of exposure.

Antimicrobials in small-scale urban pig farming in a lower middle-income country - arbitrary use and high resistance levels.

Background: Administration of antimicrobials to food-producing animals is regarded as a major contributor to the overall emergence of resistance in bacteria worldwide. However, few data are available on global antimicrobial use and resistance (AMR) in livestock, especially from low- and middle-income countries. Methods: We conducted a structured survey of 91 small-scale pig farms in the urban and peri-urban areas of Phnom Penh, Cambodia, to assess the farmers' knowledge, attitudes and practices related to antimicrobial use in their pig production. Commensal Escherichia coli was isolated from three healthy pigs from each farm (n = 261) and susceptibility testing was performed against 14 antimicrobials, using broth microdilution. Univariable logistic regression and generalized linear mixed models were used to investigate potential associations between farm characteristics, management factors and resistance to different types of antimicrobials. Results: We found a widespread and arbitrary use of antimicrobials, often based on the farmer's own judgment. Around 66% of the farmers reported frequently self-adjusting treatment duration and dosage, and 45% had not heard about the term 'antimicrobial resistance'. The antimicrobials most commonly mentioned or kept by the farmers were amoxicillin, tylosin, gentamicin and colistin. Around 37% used a feed concentrate that contained antimicrobials, while antimicrobials for humans were used as a last-line treatment by 10% of the farmers. Commensal E. coli exhibited high prevalence of resistance to several antimicrobials considered to be of critical importance for human medicine, including ampicillin, ciprofloxacin and colistin, and multidrug-resistance was found in 79% of the samples. Higher prevalence of resistance was observed on farms that administered prophylactic antimicrobials and on farms that treated the entire group or herd in the event of disease. Conclusion: The widespread and arbitrary use of antimicrobials in pig farming in Cambodia is highly worrisome. Overall, farmers had a low awareness of the risks and consequences related to antimicrobial use and AMR. The results presented in this study confirm the hypothesis that non-rational use of antimicrobials results in higher prevalence of AMR and highlight the need for professional animal health systems that involve medically rational use of antimicrobials in emerging economies such as Cambodia.

Novel foods: a risk profile for the house cricket (Acheta domesticus).

Novel foods could represent a sustainable alternative to traditional farming and conventional foodstuffs. Starting in 2018, Regulation (EU) 2283/2015 entered into force, laying down provisions for the approval of novel foods in Europe, including insects. This Approved Regulation establishes the requirements that enable Food Business Operators to bring new foods into the EU market, while ensuring high levels of food safety for European consumers. The present risk profile tackles the hazards for one of the most promising novel food insects, the house cricket (Acheta domesticus). The risk profile envisages a closed A. domesticus crickets rearing system, under Hazard Analysis and Critical Control Points (HACCP) and good farming practices (GFP), in contrast with open cricket farms. The methodology used involves screening the literature and identifying possible hazards, followed by adding relevant inclusion criteria for the evidence obtained. These criteria include animal health and food safety aspects, for the entire lifespan of crickets, based on the farm to fork One Health principle. When data were scarce, comparative evidence from close relatives of the Orthoptera genus was used (e.g. grasshoppers, locusts and other cricket species). Nevertheless, significant data gaps in animal health and food safety are present. Even if HACCP-type systems are implemented, the risk profile identifies the following considerable concerns: (1) high total aerobic bacterial counts; (2) survival of spore-forming bacteria following thermal processing; (3) allergenicity of insects and insect-derived products; and (4) the bioaccumulation of heavy metals (e.g. cadmium). Other hazards like parasites, fungi, viruses, prions, antimicrobial resistance and toxins are ranked as low risk. For some hazards, a need for additional evidence is highlighted.

Biosecurity aspects of cattle production in Western Uganda, and associations with seroprevalence of brucellosis, salmonellosis and bovine viral diarrhoea.

BACKGROUND: Many low-income countries have a human population with a high number of cattle owners depending on their livestock for food and income. Infectious diseases threaten the health and production of cattle, affecting both the farmers and their families as well as other actors in often informal value chains. Many infectious diseases can be prevented by good biosecurity. The objectives of this study were to describe herd management and biosecurity routines with potential impact on the prevalence of infectious diseases, and to estimate the burden of infectious diseases in Ugandan cattle herds, using the seroprevalence of three model infections. RESULTS: Farmer interviews (n = 144) showed that biosecurity measures are rarely practised. Visitors' hand-wash was used by 14%, cleaning of boots or feet by 4 and 79% put new cattle directly into the herd. During the 12 months preceding the interviews, 51% of farmers had cattle that died and 31% had noticed abortions among their cows. Interestingly, 72% were satisfied with the health status of their cattle during the same time period. The prevalence (95% CI) of farms with at least one seropositive animal was 16.7% (11.0;23.8), 23.6% (16.9;31.4), and 53.4% (45.0;61.8) for brucella, salmonella and BVD, respectively. A poisson regression model suggested that having employees looking after the cattle, sharing pasture with other herds, and a higher number of dead cattle were associated with a herd being positive to an increasing number of the diseases. An additive bayesian network model with biosecurity variables and a variable for the number of diseases the herd was positive to resulted in three separate directed acyclic graphs which illustrate how herd characteristics can be grouped together. This model associated the smallest herd size with herds positive to a decreasing number of diseases and having fewer employees. CONCLUSION: There is potential for improvement of biosecurity practices in Ugandan cattle production. Salmonella, brucella and BVD were prevalent in cattle herds in the study area and these infections are, to some extent, associated with farm management practices.

Knowledge, Attitudes and Practices Related to African Swine Fever Within Smallholder Pig Production in Northern Uganda.

Uganda is a low-income country with the largest pig population in East Africa. Pig keeping has a large potential, commercially and as a tool for poverty reduction, but African swine fever (ASF) is a major hurdle for development of the sector. The objective of this study was to evaluate knowledge, attitudes and practices related to ASF in the smallholder pig production value chain in northern Uganda. The study included three separate series of participatory rural appraisals (PRA), comprising purposively selected farmers and other actors in the pig production value chain. In the PRAs, various participatory epidemiology tools were used. A total of 49 PRAs and 574 participants, representing 64 different villages, were included. The results indicate that participants were well aware of the clinical signs of ASF, routes for disease spread and measures for disease control. However, awareness of the control measures did not guarantee their implementation. A majority of middlemen and butchers acknowledged having sold live pigs, carcasses or pork they believed infected with ASF. Outbreaks of ASF had a strong negative impact on participants' socio-economic status with loss of revenue and reversal into more severe poverty. In conclusion, lack of knowledge is not what is driving the continuous circulation of ASF virus in this setting. To control ASF and reduce its impact, initiatives that stimulate changes in management are needed. Because the behaviour of all actors in the value chain is largely influenced by the deep rural poverty in the region, this needs to be combined with efforts to reduce rural poverty.

Risk factors associated with Campylobacter detected by PCR in humans and animals in rural Cambodia.

Campylobacter are worldwide-occurring zoonotic bacteria, with the species Campylobacter jejuni and C. coli commonly associated with diarrhoea in children in low-income countries. In this cross-sectional study, the prevalence of C. jejuni and C. coli in human and livestock faecal samples was detected by PCR and zoonotic risk factors associated with human Campylobacter positivity were identified. In total 681 humans and 753 livestock (chickens, ducks, pigs, cattle) from 269 households were sampled. Children aged <16 years were more frequently Campylobacter positive (19%) than adults (8%) and multilevel logistic models revealed that human C. jejuni positivity was associated with the following household practices: home-slaughtering [odds ratio (OR) 2·4, P = 0·01], allowing animals access to sleeping and food preparation areas (OR 2·8, P = 0·02), and eating undercooked meat (OR 6·6, P = 0·05), while frequent consumption of beef was protective (OR 0·9, P = 0·05). Associations were stronger for home-slaughtering (OR 4·9, P = 0·004) with C. jejuni infection in children only. Campylobacter was highly prevalent in pigs (72%) and chickens (56%) and risk factors associated with human Campylobacter positivity were identified throughout the meat production chain. The findings underline the importance of studying source attributions throughout the production chain and the need for upgraded understanding of Campylobacter epidemiology in low-income countries.

Genotypic characterization to identify markers associated with putative hypervirulence in Swedish Escherichia coli O157:H7 cattle strains.

AIMS: To establish whether investigated subtyping methods could identify any specific characteristics that distinguish Swedish VTEC O157:H7 strains isolated from cattle farms associated with human enterohaemorrhagic Escherichia coli (EHEC) cases from cattle strains isolated in prevalence studies. METHODS AND RESULTS: Strains (n = 32) isolated in a dairy herd prevalence study and strains isolated from farms associated with human cases (n = 13) were subjected to typing. Partial sequencing of the vtx(2) genes could not identify any unique variants of vtx(2) or vtx(2c) in strains associated with human cases. A specific variant of VTEC O157:H7, which was overrepresented among farms associated with human cases (P = 0·01), was by two different single-nucleotide-polymorphism (SNP) assays identified as clade 8, a subgroup of VTEC O157:H7 strains considered to be putatively hypervirulent. Multi-locus variable number tandem repeat analysis (MLVA) typing of all strains produced similar results as pulsed-field gel electrophoresis (PFGE) typing regarding clustering of the strains, but MLVA distinguished slightly better among strains than PFGE. CONCLUSION: In Sweden, VTEC O157:H7 strains from the putatively hypervirulent clade 8 are overrepresented among isolates from cattle farms associated with human cases compared with VTEC O157:H7 strains isolated in prevalence studies. SIGNIFICANCE AND IMPACT OF THE STUDY: Real-time PCR SNP typing for clade 8 can be used to identify cattle farms that are at higher risk of causing EHEC infections in humans.

Microarray-based detection of virulence genes in verotoxigenic Escherichia coli O157:H7 strains from Swedish cattle.

Verotoxigenic Escherichia coli (VTEC) serotype O157:H7 strains from a Swedish cattle prevalence study (n=32), and livestock-derived strains linked to human disease (n=13), were characterized by microarray and PCR detection of virulence genes. The overall aim of the study was to investigate the distribution of known virulence determinants and determine which genes are linked to increased pathogenicity in humans. A core set of 18 genes or gene variants were found in all strains, while seven genes were variably present. This suggests that the majority of VTEC O157:H7 found in Swedish cattle carry a broad repertoire of virulence genes and should be considered potentially harmful to humans. A single virulence gene type was significantly associated with strains linked to human disease cases (P=0.012), but no genetic trait to explain the increased virulence of this genotype could be found.

Risk factors for campylobacteriosis: an epidemiological surveillance study of patients and retail poultry.

Isolates from Campylobacter jejuni-infected patients were collected and fresh poultry meat from retail sources was sampled during the same time period and within the same geographical area. The patients were interviewed about exposure to known risk factors, and a significant correlation between the presence of a poultry subtype in patients and the consumption of fresh poultry meat was observed.

Sources of sporadic Yersinia enterocolitica infection in children in Sweden, 2004: a case-control study.

Young children account for a large proportion of reported Yersinia enterocolitica infections in Sweden with a high incidence compared with other gastrointestinal infections, such as salmonellosis and campylobacteriosis. A case-control study was conducted to investigate selected risk factors for domestic sporadic yersiniosis in children aged 0-6 years in Sweden. In total, 117 cases and 339 controls were included in the study. To minimize exclusion of observations due to missing data a multiple non-parametric imputation technique was used. The following risk factors were identified in the multivariate analysis: eating food prepared from raw pork products (OR 3.0, 95% CI 1.8-5.1) or treated sausage (OR 1.9, 95% CI 1.1-3.3), use of a baby's dummy (OR 1.9, 95% CI 1.1-3.2) and contact with domestic animals (OR 2.0, 95% CI 1.2-3.4). We believe that the importance of Y. enterocolitica infection in children has been neglected and that results from this study can be used to develop preventive recommendations.

A large Escherichia coli O157 outbreak in Sweden associated with locally produced lettuce.

In 2005 a large outbreak of verotoxin-producing Escherichia coli (VTEC) occurred in Sweden. Cases were interviewed and cohort and case-control studies were conducted. Microbiological investigations were performed using polymerase chain reaction (PCR) to detect the Shiga-like toxin (Stx) genes followed by cultivation and pulsed-field gel electrophoresis. A total of 135 cases were recorded, including 11 cases of hemolytic uremic syndrome. The epidemiological investigations implicated lettuce as the most likely source of the outbreak, with an OR of 13.0 (CI 2.94-57.5) in the case-control study. The lettuce was irrigated by water from a small stream, and water samples were positive for Stx 2 by PCR. The identical VTEC O157 Stx 2 positive strain was isolated from the cases and in cattle at a farm upstream from the irrigation point. An active surveillance and reporting system was crucial and cooperation between all involved parties was essential for quickly identifying the cause of this outbreak. Handling of fresh greens from farm to table must be improved to minimize the risk of contamination.

Summary of the Swedish Campylobacter program in broilers, 2001 through 2005.

A Campylobacter monitoring program in broiler chickens was carried out in Sweden from 2001 through 2005. The objective was to reduce the occurrence of Campylobacter in the food chain through preventive measures, starting with primary production. The program involved collecting samples from all broiler flocks at slaughter and occasional additional times. The annual incidence of Campylobacter-positive slaughter batches progressively decreased from 20% in 2002 to 13% in 2005. Most of the positive batches had a high within-flock prevalence of Campylobacter. However, about 18% of the positive batches had a low-within-flock prevalence; Campylobacter spp. were isolated from at most 50% of the cloacal samples. The incidence of batches contaminated at slaughter ranged between 6 and 9% during the study period. During all 5 years, a seasonal peak of incidence was observed in the summertime. In an additional study, quantitative analyses were performed on neck skin samples and carcass rinse samples. Those results were compared with the positive and negative findings of the cloacal, cecum, and neck skin samples at slaughter. When Campylobacter was found in the cecum, there was a higher level of Campylobacter in the quantitative analyses. Those batches where Campylobacter already had been found on the farm had a higher concentration of Campylobacter than those batches in which Campylobacter was found only at slaughter. During the study period, about one-third of producers seldom delivered Campylobacter-positive batches (< 10% positive batches per year). Thus, it is possible to produce Campylobacter-free broilers in Sweden.

Feed-borne outbreak of Salmonella cubana in Swedish pig farms: risk factors and factors affecting the restriction period in infected farms.

In 2003, a feed-borne outbreak of Salmonella Cubana occurred in Sweden as a result of contamination in a feed plant. Salmonella Cubana was detected in 49 out of 77 pig farms having received possibly contaminated feed. In this study, potential risk factors for farms being salmonella positive were examined, and a survival analysis was performed to investigate risk factors affecting the restriction period for salmonella positive farms. The median restriction time for all 49 farms was 17 weeks. An increased risk for farms being salmonella infected (positive in feed and/or faeces) was seen for fattening farms and farms feeding soy. The survival analysis showed that herds with a low level of infection and farms with a high hygiene level had shorter restriction times. This study is unique as it investigates a real outbreak of feed-borne salmonella, where the source of infection was reliably identified, the period of exposure could be defined and data were collected from all exposed farms.

Annual variations in Leptospira seroprevalence among sows in southern Vietnam.

A serological survey was conducted among sows in the Mekong delta in southern Vietnam in 1999 to investigate variations in leptospiral seroprevalence over a one-year period. In this region, leptospirosis is endemic and a high leptospiral seroprevalence has been shown in the pig population. In this study, the serology of six Leptospira serovars was analysed by the microscopic agglutination test for 429 sows at five large-scale state farms sampled during the dry period, the rainy period and the early dry period. The serovars included were L. interrogans serovar (sv) autumnalis strain Akiyama A, L. interrogans sv bratislava strain Jez, L. interrogans sv icterohaemorrhagiae strain Kantorowicz, L. interrogans sv pomona strain Pomona, L. borgpetersenii sv tarassovi strain Perepelitsin, and L. kirschneri sv grippotyphosa strain Duyster. Variations in seroprevalence over the year were found for sv bratislava and sv icterohaemorrhagiae: the seroprevalence was higher during the dry period compared with the rainy period (p = 0.07 and p = 0.005, respectively) and the early dry period (p = 0.00006 and p = 0.0006, respectively). It is concluded that in regions where water is constantly abundant and where animals are exposed to the outdoor environment all year round there are highly significant variations in leptospiral seroprevalence over the year.

Risk factors for hazard of release from salmonella-control restriction on Swedish cattle farms from 1993 to 2002.

In Sweden, only a few cattle farms are infected with salmonella each year and this can be attributed to the Swedish salmonella control programme. All findings of salmonella in animals, feed and food of animal origin are notifiable and restrictions are always put on infected herds until they have been cleaned up from the infection. However, there has been concern about increasing costs for clean-up of salmonella-infected farms as well as increasing length of the restriction periods. Our aim was to investigate potential risk factors associated with the length of restriction periods on Swedish cattle farms between 1993 and late 2002. All 112 cattle farms that were notified to the Swedish Board of Agriculture as infected with salmonella during the study period, were included in this longitudinal and retrospective study. The putative risk factors were analysed using the proportional-hazards model. There was a lower hazard for release from salmonella control restrictions after the European Union (EU) accession in 1995, and/or change of testing from one to two negative herd tests for release of restrictions (hazard ratio (HR)=0.56, 95% confidence interval (CI)=0.38, 0.84), for every additional number of 100 cows (HR=0.83; CI=0.7, 0.97), if rodents and/or wild birds were abundant (HR=0.5, CI=0.27, 0.98) and if there was more than one farm site in the company (HR=0.47, CI=0.28, 0.81).

Leptospira in slaughtered fattening pigs in southern Vietnam: presence of the bacteria in the kidneys and association with morphological findings.

One kidney was collected from each of 32 fattening pigs at an abattoir in southern Vietnam in 2001 in order to demonstrate infecting Leptospira serovar and to associate renal macro- and microscopic findings with the presence of renal leptospires. Leptospires were demonstrated in 22 (69%) of the investigated kidneys by immunofluorescence. Multifocal interstitial nephritis (MFIN) and gross renal lesions (white spots) were each demonstrated in 24 (75%) kidneys. Leptospira interrogans serovar bratislava was isolated from one kidney. There was no association between presence of leptospires and MFIN (P=0.19), respectively and white spots (P=0.98), respectively. These data suggest that Leptospira infection is common among fattening pigs in the study area and that these animals may be considered as an occupational human health hazard. It is also suggested that the presence of white spots is an unreliable indicator of the presence of renal leptospires.

Salmonella isolated from animals and feed production in Sweden between 1993 and 1997.

This paper presents Salmonella data from animals, feedstuffs and feed mills in Sweden between 1993 and 1997. During that period, 555 isolates were recorded from animals, representing 87 serotypes. Ofthose, 30 serotypes were found in animals in Sweden for the first time. The majority of all isolates from animals were S. Typhimurium (n = 91), followed by S. Dublin (n = 82). There were 115 isolates from cattle, 21 from broilers, 56 from layers and 18 from swine. The majority of these isolates were from outbreaks, although some were isolated at the surveillance at slaughterhouses. The number of isolates from the feed industry was similar to that of the previous 5-year period. Most of those findings were from dust and scrapings from feed mills, in accordance with the HACCP programme in the feed control programme. It can be concluded that the occurrence of Salmonella in animals and in the feed production in Sweden remained favourable during 1993-97.