Food Safety Management System validation and verification in meat industry: Carcass sampling methods for microbiological hygiene criteria – A review

During validation and verification of the system for the proper implementation of HACCP principles, it is essential to rely on microbiological data. Considerable science research has been carried out during the last twenty years on sampling and testing of carcasses for hygiene criteria. This includes the preferable indicator microorganisms to be used, in order to indicate the general hygiene of slaughtering procedures, the evaluation of microbiological data gathered and the sampling methods. Furthermore, European Union (EU) and the United States have adopted the procedures for HACCP validation and verification in their legislation. The aim of this review is to demonstrate the relevant modern trends in this field of food science. In conclusion, microbiological data based on the indicators should be interpreted only to assess general trends in the hygiene process of the operator in order to take corrective action. Microbiological results, obtained only at the end of the slaughtering process, do not provide information on the cause of the problem. Therefore, ‘process-based’ microbiological criteria which are based on values measured at various stages of the process, including final carcass values, should be used. Finally, in order to implement an adequate monitoring system, non-destructive techniques of carcass sampling could be used instead of excision. The microbial recovery may be lower, but it is proportional to the excision recovery and therefore, non-destructive techniques, like swabbing with sponges, could be a practical sampling method for the estimation of indicators during the slaughtering procedure and hygiene evaluation.     

Potential of Escherichia coli as a surrogate indicator for postchill broiler carcasses with high Campylobacter counts

Surrogating Campylobacter contamination level in broiler carcasses with other bacterial indicators, used to evaluate the hygienic status of the slaughterline operations, might be stimulation to the broiler meat industry to improve control of Campylobacter during slaughter. Theoretically, Escherichia coli might have some practical merits as a potential indicator for carcasses contaminated with Campylobacter. This study investigates the correlation between the counts of E. coli and Campylobacter in 231 postchill broiler carcasses. The impact of setting a process hygiene target based on E. coli counts on reducing the frequency of carcasses contaminated with Campylobacter at level of ≥3 log₁₀ CFU/g was also investigated. Almost half (48.9% (46/94)) of the carcasses with enumerable Campylobacter (≥1 log₁₀ CFU/g) had E. coli counts between 3 and 4 log₁₀ CFU/g. In addition, 54.8% (17/31) of the carcasses contaminated with Campylobacter of ≥3 log₁₀ CFU/g were correlated with E. coli count range of ≥3 & <4 log₁₀ CFU/g. A theoretical scenario assuming that hygiene and processing measures could allow achieving a target for E. coli that not exceeding 3 log₁₀ CFU/g showed a parallel impact on Campylobacter contamination in broiler carcasses. In such scenario, the overall number of Campylobacter-positive carcasses could be dropped from 40.6% to 12.5%; in addition, 80.6% (25/31) of the carcasses contaminated with Campylobacter of ≥3 log₁₀ CFU/g could be eliminated. Findings from this study reveal that a hygiene target based on E. coli count could be used as an indirect sanitary tool for reducing the level of Campylobacter contamination in postchill broiler carcasses.     

Simultaneous determination of melamine and cyanuric acid in dairy products by mixed-mode solid phase extraction and GC–MS

This report described a method for simultaneous determination of cyanuric acid (CYA) and melamine (MEL) in dairy products. The samples were extracted by a mixture of acetonitrile/water and cleaned by graphite carbon/strong cation exchange (CARB/SCX) mixed-mode solid phase extraction column. The CYA and MEL were derivatized with bis(trimethylsily1)trifluoroacetamide (BSTFA) containing 1% Trimethylchlorosilane (TMCS), and quantified with the internal standards of ¹⁵N₃-cyanuric acid and ¹³C₃-melamine by GC–MS. The results indicated that CARB/SCX mixed solid phase extraction column could be used for sample pretreatment. The fortification recoveries were 80.8–101.5%, and the relative standard deviations (RSDs) were 3.6–7.9%. The detection limits of CYA and MEL were 0.025 mg kg⁻¹ and 0.01 mg kg⁻¹ respectively.     

Monitoring of the quality of modified atmosphere packaged broiler chicken cuts stored in different temperature conditions: B. Biogenic amines as quality-indicating metabolites

The formation of biogenic amines was studied in broiler chicken cuts stored in modified atmosphere (MA) packages. Also, the applicability of biogenic amines for the quality control of MA-packaged broiler chicken cuts was evaluated in various constant and variable temperature schemes. It was found that temperature dependent changes took place in the concentrations of tyramine, putrescine and cadaverine. The changes in the concentrations of these amines were in accordance with the microbiological quality of broiler chicken cuts. On the basis of the results it was concluded that tyramine, putrescine and cadaverine could serve as quality indicating tools for MA-stored poultry.     

Comparison of antibiotic resistance patterns in Listeria monocytogenes and Salmonella enterica strains pre-exposed and exposed to poultry decontaminants

Recent opinions expressed by European Union Scientific Committees suggest there is a potential for poultry decontaminants to increase resistance to antibiotics. At this moment there is no scientific information available to estimate this risk accurately. Four strains (Listeria monocytogenes serovar 1/2a, Listeria monocytogenes serovar 4b, Salmonella enterica serotype Typhimurium and Salmonella enterica serotype Enteritidis) were repeatedly exposed to increasing sub-inhibitory concentrations of decontaminants (trisodium phosphate, acidified sodium chlorite, citric acid, chlorine dioxide or peroxyacetic acid) and tested against 15 antibiotics by means of a standard disc-diffusion technique (NCCLS). The antibiotic resistance patterns of strains were compared before and after exposure to decontaminants. Intra-specific differences in antibiotic resistance patterns were found among strains. Increases in resistance to various antibiotics were observed in L. monocytogenes and S. enterica strains after exposure to chemicals (especially ASC). These results raise concerns over the application of certain poultry decontaminants, since they could contribute to the development of microbial resistance mechanisms. However, these are preliminary results derived from laboratory-based experiments. Additional studies under practical field conditions would be needed to substantiate these findings.