Treatment of cattle hides with Shellac-in-ethanol solution to reduce bacterial transferability--a preliminary study

Processing interventions for enhanced microbiological safety of beef carcasses and beef products: A review

Chilled beef is inevitably contaminated with microorganisms, starting from the very beginning of the slaughter line. A lot of studies have aimed to improve meat safety and extend the shelf life of chilled beef, of which some have focused on improving the decontamination effects using traditional decontamination interventions, and others have investigated newer technologies and methods, that offer greater energy efficiency, lower environmental impacts, and better assurances for the decontamination of beef carcasses and cuts. To inform industry, there is an urgent need to review these interventions, analyze the merits and demerits of each technology, and provide insight into 'best practice' to preserve microbial safety and beef quality. In this review, the strategies and procedures used to inhibit the growth of microorganisms on beef, from slaughter to storage, have been critiqued. Critical aspects, where there is a lack of data, have been highlighted to help guide future research. It is also acknowledge that different intervention programs for microbiological safety have different applications, dependent on the initial microbial load, the type of infrastructures, and different stages of beef processing.

Shellac as a multifunctional biopolymer: A review on properties, applications and future potential

Shellac is a physically refined form of lac resin, a natural biopolymer of animal origin obtained from tiny insects feeding on the sap of specific host trees. Shellac, in its basic form, is a polyester macromolecule composed of inter and intra esters of polyhydroxy aliphatic and sesquiterpene acids. It has been used in several industries for ages due to its exceptional properties such as film-forming, adhering, bonding, thermoplasticity, water-resistance and easy solubility in spirit and aqueous alkali solvents. From the beginning of the 21^st century, due to increasing demand for natural products, a paradigm shift in the scope and applications of shellac has been witnessed, especially in green electronics, 3D printing, stealth technology, intelligent sensors, food and pharmaceutical industries. Shellac offers enormous potential for greener technologies as a natural and environmentally friendly material. This review provides an insight into the lac in detail, covering various forms of the lac, structure, properties, different applications of shellac and its future potential. This article would benefit the researchers involved in shellac research and others looking for natural and greener alternatives to synthetic polymers in various applications.

The Impact of Cattle Hide Cleanliness Scores on Microbial Contamination of Carcasses During Slaughtering

This study aimed to investigate the effects of cleanliness scoring on the microbiological load of hide and the final contamination of cattle carcasses. Fifty cattle were classified from 1 (clean and dry) to 5 (filthy and wet). Aerobic colony count (ACC) and counts of Enterobacteriaceae (EC) and E. coli (ECC) were determined on the brisket, abdominal midline, rump, groin sites of the hides, and brisket, flank, groin, and hock of the carcasses. On hides, ACC ranged from 3.15±0.13 log cfu/cm2 in category 1 to 8.14±0.21 log cfu/cm2 in category 5. EC and ECC were ranging between 1.13±0.07 and 2.80±0.09 log cfu/cm2, and 1.21±0.05 and 2.15±0.07 log cfu/cm2, respectively. While the mean ACC on the carcasses ranged between 2.18±0.07 and 2.63±0.05 log cfu/cm2 irrespective of the categories, Enterobacteriaceae and E. coli could not be counted due to the detection limits. It was concluded that although the level of bacterial load increased significantly (P<0.001) with the increasing cleanliness category on the hide of the animals, the reflection of this increasing trend on carcasses and different parts of the carcasses were inconsistent and the hygiene provided in the slaughterhouse and processing line was the main factor to reduce cross-contamination during processing.

Beef abattoir interventions in a risk-based meat safety assurance system

In risk-based meat safety assurance system, the use of interventions is intended to accomplish the meat safety targets on chilled carcasses, particularly in situations when an abattoir is unable to sufficiently reduce risks arising from specific farms/animal batches by using process hygiene alone. Furthermore, interventions are considered whenever food safety authorities identify meat production processes associated with high risks for consumers. This paper overviews the role of beef interventions in a risk-based, meat safety assurance system. Cattle hide interventions (chemical hide washes and microbial immobilisation treatment with shellac) and beef carcass interventions (pasteurisation treatments with hot water and/or steam and organic (lactic) acid washes), show consistent reduction effects of aerobic bacteria and faecal indicators and reduced prevalences of naturally present VTEC and Salmonella. The review also identified interventions where there was a lack of data and further research was needed, and other contextual factors to inform the risk management decisions for further development of risk-based meat safety assurance system.

Peri- and Postharvest Factors in the Control of Shiga Toxin-Producing Escherichia coli in Beef

Certain Shiga toxin-producing Escherichia coli (STEC) strains are important causes of food-borne disease, with hemorrhagic colitis and, in some cases, hemolytic-uremic syndrome as the clinical manifestations of illness. Six serogroups and one serotype of STEC (O26, O45, O103, O111, O121, O145, and O157:H7) are responsible for the vast majority of cases in the United States. Based on recent data for all food commodities combined, 55.3% and 50.0% of the outbreaks of STEC O157 and non-O157 in the United States, respectively, are attributable to beef as a food source. Consequently, the U.S. Department of Agriculture, Food Safety and Inspection Service declared these organisms as adulterants in raw, nonintact beef. In North America, cattle are a major reservoir of STEC strains, with organisms shed in the feces and contaminated hides of the animals being the main vehicle for spread to carcasses at slaughter. A number of peri- and postharvest interventions targeting STEC have been developed, and significant progress has been made in improving the microbiological quality of beef in the past 20 years as a result. However, continued improvements are needed, and accurate assessment of these interventions, especially for non-O157 STEC, would greatly benefit from improvements in detection methods for these organisms.

The innovative safe fixative for histology, histopathology, and immunohistochemistry techniques: "pilot study using shellac alcoholic solution fixative"

The concerns over health and workplace hazards of formalin fixative, joined to its cross-linking of molecular groups that results in suboptimal immunohistochemistry, led us to search for an innovative safe fixative. Shellac is a natural material which is used as a preservative in foods and pharmaceutical industries. This study was undertaken to evaluate the fixation adequacy and staining quality of histopathological specimens fixed in the "shellac alcoholic solution" (SAS), and also to determine the validity of immunohistochemical staining of SAS-fixed material in comparison to those fixed in formalin. Fresh samples from 26 cases from various human tissues were collected at the frozen section room of King Abdulaziz University Hospital, and fixed in SAS fixative or in neutral buffered formaldehyde (NBF) for 12, 18, 24, and 48 h, and processed for paraffin sectioning. Deparaffinized sections were stained with hematoxylin and eosin (H&E) and immunostained for different antigens. The tissues fixed in SAS for >18 h showed best staining quality of H&E comparable to NBF-fixed tissues. Comparison of the immunohistochemical staining of different tissues yielded nearly equivalent readings with good positive nuclear staining quality in both fixatives. These findings support the fixation and preservation adequacy of SAS. Furthermore, it was concluded that the good staining quality obtained with SAS-fixed tissues, which was more or less comparable with the quality obtained with the formalin fixed tissues, supports the validity of this new solution as a good innovative fixative.

Microbial pathogen control in the beef chain: recent research advances

Within a recent EU research project ("ProSafeBeef"), research on foodborne pathogens in the beef chain was conducted by using a longitudinally integrated (fork-to-farm) approach. There is not any "single intervention-single chain point" combination by which the pathogens would be reliably and entirely eliminated from the chain resulting in total prevention of pathogens in beef and products thereof at the consumption time. Rather, a range of control interventions have to be applied at multiple points of the chain, so to achieve an acceptable, ultimate risk reduction. Various novel interventions were developed and evaluated during the project, and are briefly summarized in this paper. They include on-farm measures, risk categorisation of cattle presented for slaughter, hygiene-based measures and antimicrobial treatments applied on hides and/or carcasses during cattle slaughter, those applied during beef processing-storage-distribution, use of Time Temperature Integrator-based indicators of safety, and effective sanitation of surfaces.

Synergistic effects of lactic acid and sodium dodecyl sulfate to decontaminate Escherichia coli O157:H7 on cattle hide sections

The objective of this study was to investigate the antibacterial properties of chitosan acetate (CA), sodium dodecyl sulfate (SDS), lactic acid (LA) and their synergism when combined against a nontoxigenic strain of Escherichia coli O157:H7. Treatments that significantly reduced the concentration of E. coli O157:H7 in vitro by more than two logs were further investigated using a cattle hide decontamination model. In vitro treatments included CA (1% chitosan in 1% acetic acid vol/vol), SDS (1% vol/vol), SDS (2% vol/vol), LA (1% vol/vol), CA-SDS combination (1% chitosan in 1% acetic acid vol/vol mixed with 1% SDS vol/vol), and LA-SDS combination in two different concentrations (1% LA mixed with 1% SDS vol/vol, and 1% LA mixed with 2% SDS vol/vol). Butterfield's Phosphate Buffer water was used as a control. The antibacterial effect of 1% CA solution alone and in combination with 1% SDS in vitro resulted in a 1.8 and 1.7 log colony-forming units (CFU)/mL reduction, respectively (p<0.05). Only 1% LA, 1% SDS, 2% SDS and their combinations resulted in a >2 log reduction in E. coli O157:H7. On hide sections, both 1% LA-1% SDS and 1% LA-2% SDS combinations significantly (p<0.05) reduced E. coli O157:H7 concentration by 4.6 and 4.7 log CFU/ cm(2) greater than the control, respectively. There was no significant difference in the antibacterial effect of 1% LA compared to the control, 2% SDS compared to the control, or 1% LA compared to 2% SDS. Hence, the antibacterial efficacy of 1% LA against E. coli O157:H7 on hide sections was significantly enhanced when combined with 1% SDS. Results of this study support the use of low concentration LA-SDS combination as a hide wash to reduce the risk of E. coli O157:H7 contamination.

Inactivation of Escherichia coli O157:H7 on cattle hides by caprylic acid and β-resorcylic acid

Two naturally occurring, generally recognized as safe compounds, namely, caprylic acid (CA) (1%) and b -resorcylic acid (BR) (1%), and their combination, applied at 23 and 60°C were evaluated for their antimicrobial effects against Escherichia coli O157:H7 on cattle hides in the presence and absence of bovine feces. Fresh cleaned cattle hides were cut into pieces (5 cm(2)), air dried, and inoculated with a five-strain mixture of nalidixic acid-resistant (50 μg/ml) E. coli O157:H7 (∼8.0 log CFU). The hide samples were air dried under a biosafety hood for 2 h and sprayed with 95% ethanol, 1% CA, 1% BR, or a mixture of 1% CA and 1% BR at 23 or 60°C. The hide samples were kept at 23°C, and E. coli O157:H7 populations were determined at 2 and 5 min after treatment. Both CA and BR were effective in decreasing E. coli O157:H7 populations on hides by 3 to 4 log CFU/cm(2) (P < 0.05). Sterile bovine feces had no effect on the decontaminating property of CA and BR on cattle hides (P > 0.05). Results of this study indicate that CA and BR could potentially be used to decontaminate cattle hides, but follow-up research under slaughterhouse conditions is warranted.

Efficacy of octenidine hydrochloride for reducing Escherichia coli O157:H7, Salmonella spp., and Listeria monocytogenes on cattle hides

The efficacy of octenidine hydrochloride (OH; 0.025, 0.15, and 0.25%) for inactivating Escherichia coli O157:H7, Salmonella spp., and Listeria monocytogenes on cattle hides was investigated at 23°C in the presence and absence of bovine feces. All tested concentrations of OH were effective in decreasing more than 5.0 log CFU of bacteria/cm(2) in 5 min (P < 0.01). The results suggest that OH could be used to decontaminate cattle hides; however, further studies under commercial settings are necessary to validate these results.