Microbiological and chemical evaluation of dairy products commercialized in the Lebanese market

Abstract

Background and Aim: Cheese is considered an essential component of the Lebanese table, however, several foodborne illnesses have been reported due to cheese consumption. This study aimed to assess the microbiological quality and the occurrence of antibiotic and pesticide residues in two traditional Lebanese cheeses, Akkawi and Baladiyeh. In addition, drug resistance of isolated pathogens from the cheese samples was evaluated. Materials and Methods: Fifty Akkawi and Baladiyeh cheese samples were obtained in duplicate from 37 different commercial brands in supermarkets and shops from various regions of Lebanon. Samples of different weights were either individually vacuum packed or soaked in brine unpacked where it was placed in plastic bag after being purchased. Samples were homogenized to determine antibiotic and pesticide residues using liquid and gas chromatography coupled to mass spectrometry, and microbiological evaluation was performed according to the International Organization for Standardization reference analytical methods. The disk diffusion method was used to determine the susceptibility of these isolates to antibiotics. Results: Microbiologically, 17% of Akkawi and 14% of Baladiyeh samples were found to be non-conforming. The bacterial isolates (n = 29) were tested for their susceptibility to 11 different antibiotics commonly prescribed in the Lebanese community or used for treating infections caused by Gram-negative bacteria and listeriosis. Each isolate was found to be resistant to at least three antibiotics. Liquid and gas chromatography coupled to mass spectroscopy analysis showed the absence of pesticide residues in all samples. However, sulfamethazine antibiotic residue was found in 14% of the samples. Conclusion: The results suggest that the cheese samples tested could cause foodborne illnesses due to the detection of pathogenic bacteria and are a public health concern due to the presence of antibiotic residues and the transmission of multidrug-resistant organisms.

Assessment of the Microbiological Acceptability of White Cheese (Akkawi) in Lebanon and the Antimicrobial Resistance Profiles of Associated Escherichia coli

“…We also found that 80% of the cheese samples would be rejected (deemed unacceptable for human consumption) based on the E. coli densities and LIBNOR standards (2002:223 and 2003:495), while up to 32% of the samples would be rejected based on S. aureus densities ( Figure 1 ). Therefore, this study reported higher non-conformity rates in comparison to the limited studies available on dairy products in Lebanon [ 14 , 21 ]. Beyond the use of bacterial indicators, it is known that the enterotoxins secreted by S. aureus can cause gastrointestinal disease [ 9 ].…”

“…The high prevalence of MDR E. coli in Akkawi cheese was not surprising ( Figure 2 and Figure 3 ; Table 1 ), because several studies have reported a widespread antibiotic resistance in the Lebanese community, as well as in environmental and food matrices [ 29 , 34 , 35 , 37 , 38 , 39 , 46 ]. A recent study on dairy products in Lebanon screened 29 E. coli isolates that were found to be resistant to AMC (69% of isolates), CFM (11%), CHL (31%), and STR (100%), and all the tested isolates were multidrug-resistant [ 21 ]. However, in the aforementioned study, the number of E. coli isolates (n = 29) and antibiotics tested was very limited.…”

“…Therefore, it is critical to assess the safety of important foods in Lebanon. However, only a limited number of studies have investigated the microbiological and chemical safety of cheese [ 14 , 21 ].…”

“…Notably, the misuse of antimicrobials and the alarmingly high prevalence of drug resistance are also well-documented in the agricultural and environmental settings in Lebanon [ 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 ]. However, reports on the dissemination of antimicrobial resistance (AMR) in food commodities, especially dairy products, are scarce and these issues have not been thoroughly investigated in Lebanon [ 21 , 36 ]. Therefore, it was necessary to investigate the antimicrobial resistance profile of the bacterial contaminants in cheese in Lebanon.…”

Contamination of Kazakhstan cheeses originating from Escherichia coli and its resistance to antimicrobial drugs

“…The data obtained were interpreted in accordance with EUCAST 2021 (EUCAST, 2021) and Clinical and Laboratory Standards Institute (CLSI) 2019 (CLSI, 2019). Isolates of bacteria that are resistant to at least three classes of antibiotics have been classified as multidrug-resistant microorganisms [ 24 ].…”