Characterization of highly pathogenic avian influenza virus in retail dairy products in the US.

In March 2024, clade 2.3.4.4b H5N1 highly pathogenic avian influenza virus (HPAIV) was detected in dairy cattle in the US, and it was discovered that the virus could be detected in raw milk. Although affected cow's milk is diverted from human consumption and current pasteurization requirements are expected to reduce or eliminate infectious HPAIV from the milk supply, a study was conducted to characterize whether the virus could be detected by quantitative real-time RT-PCR (qrRT-PCR) in pasteurized retail dairy products and, if detected, to determine whether the virus was viable. From 18 April to 22 April 2024, a total of 297 samples of Grade A pasteurized retail milk products (23 product types) were collected from 17 US states that represented products from 132 processors in 38 states. Viral RNA was detected in 60 samples (20.2%), with qrRT-PCR-based quantity estimates (non-infectious) of up to 5.4log1050% egg infectious doses per mL, with a mean and median of 3.0log10/mL and 2.9log10/mL, respectively. Samples that were positive for type A influenza by qrRT-PCR were confirmed to be clade 2.3.4.4 H5 HPAIV by qrRT-PCR. No infectious virus was detected in any of the qrRT-PCR-positive samples in embryonating chicken eggs. Further studies are needed to monitor the milk supply, but these results provide evidence that the infectious virus did not enter the US pasteurized milk supply before control measures for HPAIV were implemented in dairy cattle.IMPORTANCEHighly pathogenic avian influenza virus (HPAIV) infections in US dairy cattle were first confirmed in March 2024. Because the virus could be detected in raw milk, a study was conducted to determine whether it had entered the retail food supply. Pasteurized dairy products were collected from 17 states in April 2024. Viral RNA was detected in one in five samples, but infectious virus was not detected. This provides a snapshot of HPAIV in milk products early in the event and reinforces that with current safety measures, infectious viruses in milk are unlikely to enter the food supply.

Bacteriophages on dairy foods.

This review focuses on the impact of bacteriophages on the manufacture of dairy foods. Firstly, the impact of phages of lactic acid bacteria in the dairy industry, where they are considered enemies, is discussed. The sources of phage contamination in dairy plants are detailed, with special emphasis on the rise of phage infections related to the growing use of cheese whey as ingredient. Other topics include traditional and new methods of phage detection, quantification and monitoring, and strategies of phage control in dairy plants, either of physical, chemical or biological nature. Finally, the use of phages or purified phage enzymes as allies to control pathogenic bacteria in the food industry is reviewed.

Phages for biocontrol in foods: What opportunities for Salmonella sp. control along the dairy food chain?

Controlling the presence of pathogenic bacteria, such as Salmonella sp., in dairy products production is a burning issue since contamination with Salmonella can occur at any stage of the production chain. The use of Salmonella-phages applied as control agents has gained considerable interest. Nonetheless, Salmonella-phage applications specifically intended for ensuring the safety of dairy products are scarce. This review identifies recent advances in the use of Salmonella-phages that are or could be applied along the dairy food chain, in a farm-to-fork approach. Salmonella-phages can be promising tools to reduce the shedding of Salmonella in cattle, and to reduce and control Salmonella occurrence in postharvest food (such as food additives), and in food processing facilities (such as biosanitizing agents). These control measures, combined with existing methods and other biocontrol agents, constitute new opportunities to reduce Salmonella occurrence along the dairy food production, and consequently to alleviate the risk of Salmonella contamination in dairy products.

[Milk raw materials from retrovirus infected cows: questions of safety and quality of produced products].

The comparative evaluation of protein biological value of curd manufactured by the traditional technology and using microbial transglutaminase has been carried out. The biological experiment was conducted at Wistar laboratory rats fed by the analyzed curd samples as the protein (in the amount of 10% of the total calorie content of the diet) composed of semisynthetic diet. Within 22 days the individual rates of feed eating and the rat's body weight gain have been analyzed. During the exchanged period (from 23 to 24 days) besides the listed readings the amount of nitrogen egested with faeces and urine has been considered. The protein biological value of curd produced with transglutaminase and according to the traditional technology was evaluated by determination of protein efficiency coefficient, true nitrogen absorbency, nitrogenous balance. Besides, at the end of the exchanged period the blood immune component and protein catabolism by means of biochemical blood serum analysis has been evaluated. The results of in vitro analyses make it possible to state the assumption regarding the curd biological value improvement and digestibility of curd protein by means of milk proteins fermentative modification. The revealed reliable increase of the total protein concentration (by 4%), urea nitrogen (over 20%) and creatinine level correlated with high protein amount in the tested product consumed by rats within the exchanged period. The detected reduction of leucocytes and lymphocytes amount in blood of rats consuming the tested curd samples testified the reasonability of the additional investigation of immune reactions. The calculation of the indicators characterizing the biological value of curd protein based on its amino acid composition showed the increase of amino acid imbalance in curd produced with transglutaminase mainly due to lysine excess and the corresponding reduction of assimilability by 1.7%.

Can 'cow flu' be eliminated-or is it too late?

Feeble government response and lack of industry cooperation hamper U.S. control efforts.

Attribution of foodborne illnesses, hospitalizations, and deaths to food commodities by using outbreak data, United States, 1998-2008.

Each year, >9 million foodborne illnesses are estimated to be caused by major pathogens acquired in the United States. Preventing these illnesses is challenging because resources are limited and linking individual illnesses to a particular food is rarely possible except during an outbreak. We developed a method of attributing illnesses to food commodities that uses data from outbreaks associated with both simple and complex foods. Using data from outbreak-associated illnesses for 1998-2008, we estimated annual US foodborne illnesses, hospitalizations, and deaths attributable to each of 17 food commodities. We attributed 46% of illnesses to produce and found that more deaths were attributed to poultry than to any other commodity. To the extent that these estimates reflect the commodities causing all foodborne illness, they indicate that efforts are particularly needed to prevent contamination of produce and poultry. Methods to incorporate data from other sources are needed to improve attribution estimates for some commodities and agents.

Short communication: Characterization of Shiga toxin 2-carrying bacteriophages induced from Shiga-toxigenic Escherichia coli isolated from Italian dairy products.

Forty samples of raw milk cheese and 25 samples of raw milk itself were subjected to enrichment culture for Shiga-toxigenic Escherichia coli (STEC), and a single Shiga toxin 2- (Stx(2)) positive strain was obtained from one of the cheese samples. Thus, aged cheeses in which the curd is subsequently heat treated (48°C) cannot be presumed to be STEC free. Infective Stx(2) bacteriophages were induced from 3 STEC strains isolated elsewhere from raw milk and 1 STEC strain from aged cheese sourced in Italy. Data on E. coli host range, morphology, genome size, and genetic variation determined by restriction fragment length polymorphism and multi-locus genotyping are presented. Although all 4 bacteriophages were found to be short-tailed Podoviridae, they exhibited considerable variation in both genome size and content. This extended to the Stx(2) genes themselves, whose sequences contained several point mutations, but these did not translate to amino acid substitutions.

Epidemiology and distribution of tick-borne encephalitis.

Tick-borne encephalitis (TBE) is the main tick-borne virus infection in Eurasia. It is prevalent across the entire continent from Japan to France and occurs in endemic foci. Expansion of prevalence in areas including northern Russia, Sweden, and Finland has been observed in recent years. Ticks are the most important vectors and may transmit the TBE virus to animals and humans. TBE can also be transmitted to humans in milk containing the virus. TBE has been implicated as a travel-acquired illness and there are isolated reports of its occurrence in countries outside the known areas of prevalence. Therefore, TBE should be included in the differential diagnosis for all central nervous system diseases inside or outside endemic areas.

Temperate and virulent Lactobacillus delbrueckii bacteriophages: comparison of their thermal and chemical resistance.

The aim of this work was to study the efficiency of diverse chemical and thermal treatments usually used in dairy industries to control the number of virulent and temperate Lactobacillus delbrueckii bacteriophages. Two temperate (Cb1/204 and Cb1/342) and three virulent (BYM, YAB and Ib3) phages were studied. The thermal treatments applied were: 63 degrees C for 30 min (low temperature--long time, LTLT), 72 degrees C for 15 s (high temperature--short time, HTST), 82 degrees C for 5 min (milk destined to yogurt elaboration) and 90 degrees C for 15 min (FIL-IDF). The chemical agents studied were: sodium hypochlorite, ethanol, isopropanol, peracetic acid, biocides A (quaternary ammonium chloride), B (hydrogen peroxide, peracetic acid and peroctanoic acid), C (alkaline chloride foam), D (p-toluensulfonchloroamide, sodium salt) and E (ethoxylated nonylphenol and phosphoric acid). The kinetics of inactivation were drew and T(99) (time necessary to eliminate the 99% of phage particles) calculated. Results obtained showed that temperate phages revealed lower resistance than the virulent ones to the treatment temperatures. Biocides A, C, E and peracetic acid showed a notable efficiency to inactivate high concentrations of temperate and virulent L. delbrueckii phages. Biocide B evidenced, in general, a good capacity to eliminate the phage particles. Particularly for this biocide virulent phage Ib3 showed the highest resistance in comparison to the rest of temperate and virulent ones. On the contrary, biocide D and isopropanol presented a very low capacity to inactivate all phages studied. The efficiency of ethanol and hypochlorite was variable depending to the phages considered. These results allow a better knowledge and give useful information to outline more effective treatments to reduce the phage infections in dairy plants.

Prevalence of bacteriophages infecting Staphylococcus aureus in dairy samples and their potential as biocontrol agents.

The prevalence of bacteriophages infecting Staphylococcus aureus in dairy samples was assessed. Fourteen Staph. aureus strains were used in enrichment cultures of 75 dairy samples. All samples grew specific Staph. aureus bacteriophages. According to the host range, 8 different phages were isolated. Three of them, phages PhiH5, PhiG7, and PhiA72, were found in 89% of the samples; all the isolated phages were temperate. Phages PhiH5 and PhiA72 were used in preliminary bacterial challenge tests against Staph. aureus in milk. A phage mixture (1:1) was more effective than each single phage, most likely by preventing the survival of lysogenized cells. Phages inhibited Staph. aureus in UHT and pasteurized whole-fat milk. However, the phages were less active in semi-skimmed raw milk and little inhibition was achieved in whole, raw milk. Killing of Staph. aureus was observed at room temperature and at 37 degrees C, but not at refrigeration temperature.

Alimentary transmission of tick-borne encephalitis in the Czech Republic (1997-2008).

OBJECTIVES: Analysis of cases of tick-borne encephalitis (TBE) with confirmed food-borne transmission in patients who were unaware of tick attachment prior to the onset of illness. MATERIAL AND METHODS: Data on laboratory confirmed cases of TBE reported in the Czech Republic (CR) in 1997-2008 were obtained from the EPIDAT system. Patient interview data were recorded in a standardised questionnaire form with multiple choices for locality (GIS) and route of transmission to be exported on a weekly basis in electronic form to a protected database of the Ministry of Health of CR. Statistical processing was conducted by ANOVA using Epi-Info CDC Atlanta and STATCALC software. RESULTS: TBE has been recognised in CR since 1948 when, for the first time ever in Europe, the TBE virus was isolated from patients and I. ricinus ticks in two Czech and Moravian areas simultaneously (and independently of one another). TBE cases in the Czech Republic have been reported since 1971. In 1997 - 2008 the incidence ranged between 422 cases (1998) to 1029 cases (2006). Food-borne transmission of TBE was first reported in Czechoslovakia in 1954. At that time, nothing was known of the possibilities of arbovirus transmission by the food-borne route; this was discovered following the TBE epidemic of 1951 in the east Slovak town of Roznava in which 660 persons were infected, and of these, 271 were hospitalised. The source of infection was contaminated goats' milk which had been mixed into dairy milk at the local dairy and distributed without pasteurization. The risk of TBE transmission by unpasteurized goats' milk is associated with the current trend of I. ricinus tick proliferation in foothills and mountainous areas. The shift of the line of their spread from 700 m above sea level to 1200 m means that to up to 8% of the area of the CR (6300 km2) have been newly colonized by ticks. In 1997 - 2008, 64 cases of TBE were recorded in patients who reported consumption of unpasteurized goats' and dairy milk or unpasteurized sheep's milk cheese. The majority of cases involved goats' milk (36 patients, i.e. 56.3%) and sheep's milk cheese (21 patients, i.e. 32.8%). Dairy milk-borne infection was responsible for 7 TBE cases (10.9%). Of the 64 patients with food-borne TBE, 33 were men (51.6%) and 31 women (48.4%). Thirty-three cases (51.6%) occurred in family outbreaks following purchase of cheese or milk from animal breeders. Twenty-two cases (34.4%) occurred in individual patients and for 9 cases (14.0%) the data are unavailable. The highest age-specific morbidity, i.e. 1.94/100 000, was observed amongst the 5 - 9 years age-group, while in the adult age-groups the rates ranged between 0.17/100 00 (75+ years) and 0.89/100 00 (35 - 44 years). The comparison of TBE cases in child and adult age groups revealed that children in the food-borne TBE group had a 2.5 fold risk of TBE infection over adults. None of the TBE patients was vaccinated against TBE. CONCLUSION: In 1997 - 2008, a total of 7288 cases of TBE were reported. Sixty-four (0.9%) TBE cases were food-borne. In the majority of these cases, TBE virus was transmitted by unpasteurized goats' milk and caused family outbreaks. The deciding factor in these outbreaks was an attempt to provide healthy diet to offspring.

A specific class of infectious agents isolated from bovine serum and dairy products and peritumoral colon cancer tissue.

The in silico analyses of 109 replication-competent genomic DNA sequences isolated from cow milk and its products (97 in the bovine meat and milk factors 2 group - BMMF2, and additional 4 in BMMF1) seems to place these in a specific class of infectious agents spanning between bacterial plasmid and circular ssDNA viruses. Satellite-type small plasmids with partial homology to larger genomes, were also isolated in both groups. A member of the BMMF1 group H1MBS.1 was recovered in a distinctly modified form from colon tissue by laser microdissection. Although the evolutionary origin is unknown, it draws the attention to the existence of a hitherto unrecognized, broad spectrum of potential pathogens. Indirect hints to the origin and structure of our isolates, as well as to their replicative behaviour, result from parallels drawn to the Hepatitis deltavirus genome structure and replication.

Inactivation of Dairy Bacteriophages by Thermal and Chemical Treatments.

This article provides information on the characteristics of diverse phages of lactic acid bacteria and highlights the incidence of their presence in different dairy fermentations. As it is known, thermal treatments on raw milk and use of sanitizers in the disinfection of surfaces and equipment are strategies usually applied in dairy to prevent bacteriophage infections. In this sense, this review mainly focuses on the existing data about the resistance against thermal treatments and sanitizers usually used in the dairy industry worldwide, and the differences found among bacteriophages of diverse genera are remarked upon. Also, we provide information concerning the problems that have arisen as a consequence of the potential presence of bacteriophages in cheese whey powder and derivatives when they are added in fermented dairy product manufacturing. Finally, some important conclusions on each topic are marked and checkpoints to be considered are suggested.

Slovakia reports highest occurrence of alimentary tick-borne encephalitis in Europe: Analysis of tick-borne encephalitis outbreaks in Slovakia during 2007-2016.

BACKGROUND: Slovakia is well-known for tick-borne encephalitis alimentary (TBE) outbreaks in Europe for a long time. Since the first known and largest TBE alimentary outbreak in 1951 (at territory of Slovakia) until today, none of the European countries report a comparable number of TBE alimentary outbreaks with probable and laboratory confirmed food transmission factor as Slovakia. METHODS: We analyzed TBE outbreak confirmed cases reported in Slovakia from web-based Epidemiological Information System (EPIS) during the period 2007-2016. RESULTS: During years 2007-2016 we recorded 26 TBE alimentary outbreaks. In most outbreaks (22 out of 26) the probable transmission factor of TBE virus was identified within epidemiological context. In 4 outbreaks the transmission factor was laboratory confirmed. The most common probable and confirmed transmission factor of alimentary TBE outbreaks was milk and milk products of goat origin. CONCLUSION: There should be more effort of laboratory clarification of TBE transmission factor in Slovakia. It is important to be aware of the issue of Slovakia from the point of tourism and prevention, but also due to potential risks of consumption of raw milk and its products that became popular in recent years not only in Slovakia.

Vaccinia virus detection in dairy products made with milk from experimentally infected cows.

Vaccinia virus (VACV) is the agent of bovine vaccinia (BV), an emerging zoonosis that causes exanthematic lesions on the teats of dairy cows and on the hands of milkers. The virus has been detected in the milk of naturally infected cows. The objective of this study was to investigate and quantify VACV DNA as well as the presence of infectious virus particles in samples of cheese curd, cheese whey and pasteurized milk produced using milk from cows experimentally inoculated with VACV-GP2, a Brazilian isolate of VACV (VACV-BR). VACV DNA was detected in samples of cheese and pasteurized milk at different time points, even after the resolution of the typical lesions caused by VACV, which occurred after 22 days post-infection (dpi), on average. Moreover, it was possible to detect infectious viral particles in cheese samples on alternate days until 27 dpi. The presence of both VACV DNA and infectious viral particles in cheese samples throughout the clinical course of BV and even after the disappearance of the typical clinical signs of disease draws attention to the risk associated with consumption of the cheese. Furthermore, VACV-contaminated milk and cheese may represent an occupational risk to cheesemakers who often manipulate milk and cheese curd without wearing gloves.

Pigs, pooches and pasteurisation: The changing face of brucellosis in Australia

BACKGROUND: Brucellosis, also known as undulant, Mediterranean or Malta fever, is a systemic infection that causes fever, sweats, arthralgias and myalgias. A globally important disease, brucellosis is re-emerging in Australia in association with feral pig hunting activities. OBJECTIVE: This article aims to provide clinicians with an overview of brucellosis, covering epidemiology, clinical features, diagnosis, management and prevention. DISCUSSION: Brucellosis should be suspected in all patients with non-specific, flu-like illness who fall into one of the major risk groups (feral pig hunters, overseas travellers and migrants). Depression is common and often severe, relative to other symptoms. Early diagnosis and treatment are important for preventing complications, which include osteoarticular, genitourinary or, more rarely, neurological or cardiovascular diseases. Diagnosing acute infections is based on serology and blood cultures; imaging and biopsy may be required for diagnosis of focal infections. Dual therapy with doxycycline and gentamicin is the recommended treatment. Relapse occurs in up to 10% of patients. Prevention is achieved through the use of protective gear during hunting and avoidance of unpasteurised dairy products in countries where occur in animals.

Dromedary Camels and the Transmission of Middle East Respiratory Syndrome Coronavirus (MERS-CoV).

Middle East respiratory syndrome coronavirus (MERS-CoV) is an existential threat to global public health. The virus has been repeatedly detected in dromedary camels (Camelus dromedarius). Adult animals in many countries in the Middle East as well as in North and East Africa showed high (>90%) seroprevalence to the virus. Middle East respiratory syndrome coronavirus isolated from dromedaries is genetically and phenotypically similar to viruses from humans. We summarize current understanding of the ecology of MERS-CoV in animals and transmission at the animal-human interface. We review aspects of husbandry, animal movements and trade and the use and consumption of camel dairy and meat products in the Middle East that may be relevant to the epidemiology of MERS. We also highlight the gaps in understanding the transmission of this virus in animals and from animals to humans.

Bovine leukemia virus linked to breast cancer in Australian women and identified before breast cancer development.

Bovine leukemia virus (BLV), a common virus of cattle globally, was believed for decades not to infect humans. More recent techniques (in situ PCR and DNA sequencing) enabled detection of BLV in human breast tissue, and determination of its significant association with breast cancer in a US population. Using similar techniques to study 96 Australian women, we report here detection of retrotranscribed BLV DNA in breast tissue of 40/50(80%) of women with breast cancer versus 19/46(41%) of women with no history of breast cancer, indicating an age-adjusted odds ratio and confidence interval of 4.72(1.71-13.05). These results corroborate the findings of the previous study of US women with an even higher odds ratio for the Australian population. For 48 of the subjects, paired breast tissue samples, removed 3-10 years apart in two unrelated procedures, were available. For 23/31 (74%) of these, in which the first specimen was diagnosed as nonmalignant (benign or premalignant) and the second as malignant, BLV was already present in benign breast tissue years 3-10 years before the malignancy was diagnosed. This is consistent with the supposition of a causative temporal relationship between BLV infection and subsequent development of cancer.

Detection of noroviruses in foods: a study on virus extraction procedures in foods implicated in outbreaks of human gastroenteritis.

Disease outbreaks in which foods are epidemiologically implicated as the common source are frequently reported. Noroviruses and enteric hepatitis A viruses are among the most prevalent causative agents of foodborne diseases. However, the detection of these viruses in foods other than shellfish is often time-consuming and unsuccessful. In this study, three virus concentration methods were compared: polyethylene glycol (PEG) plus NaCl, ultracentrifugation, and ultrafiltration. Two RNA extraction methods, TRIzol and RNeasy Mini Kit (Qiagen), were compared for detection of viruses in whipped cream and lettuce (as representatives of the dairy and vegetable-fruit food groups, respectively). A seeding experiment with canine calicivirus was conducted to determine the efficiency of each virus extraction procedure. The PEG-NaCl-TRIzol method was most efficient for the detection of viruses in whipped cream and the ultracentrifugation-RNeasy-Mini Kit procedure was best for detection on lettuce. Based on the seeding experiments, food items implicated in norovirus-associated gastroenteritis outbreaks were subjected to the optimal procedure for a specific composition and matrix. No noroviruses were detected in the implicated food items, possibly because the concentration of virus on the food item was too low or because of the presence of inhibitory factors. For each food group, a specific procedure is optimal. Inhibitory factors should be controlled in these procedures because they influence virus detection in food.

Characterization of a new virulent phage (MLC-A) of Lactobacillus paracasei.

A new virulent bacteriophage (MLC-A) was recently isolated in Argentina from a probiotic dairy product containing a strain of Lactobacillus paracasei. Observation of the lysate with an electron microscope revealed bacteriophage particles with an icosahedral capsid of 57 +/- 2 nm; with a collar and a noncontractile tail of 156 +/- 3 nm terminating with a baseplate to which a tail fiber was attached. Therefore, phage MLC-A belongs to the Siphoviridae family. This phage was able to survive the pasteurization process and was resistant to alcohols and sodium hypochlorite (400 mg/kg). Only peracetic acid could inactivate high-titer suspensions of phages in a short time. The maximum rates of phage adsorption to its host cells were obtained at 30 degrees C with a pH between 5 and 7, and in the presence of calcium or magnesium ions. The host range of phage MLC-A encompassed L. paracasei and Lactobacillus casei strains, but it was not able to infect Lactobacillus rhamnosus or Lactobacillus gasseri strains. One-step growth kinetics of its lytic development revealed latent and burst periods of 30 and 135 min, respectively, with a burst size of about 69 +/- 4 plaque-forming units per infected cell. Phage MLC-A had a distinctive restriction profile when compared with the 2 well-studied Lactobacillus phages, PL-1 and J-1. The genome size of the MLC-A phage was estimated to be approximately 37 kb. This study presents the description of the first phage specific for L. paracasei isolated in Argentina. The isolation of phage MLC-A indicates that, beside lactic acid bacteria starters, probiotic cultures can also be sensitive to virulent phages in industrial processes.