Microbiological food safety is strongly correlated with the hygienic practices and the quality of raw materials during the food processing procedure. It has been studied by Verran et al. 2008 that the quality of raw materials and hygienic practices on farms and in the food processing plants stretch and impact on microbiology food safety. This is due to the results of the present study showed that both raw milk and raw meat material were frequently contaminated with particular bacteria, in some cases up to 100% of the collected samples. These bacteria can directly penetrate into food products or can persist in the food processing environment as secondary contaminants (Ray & Bhunia 2007). Therefore, it is important to identify potential sources of food contamination in order to develop effective sanitation and food processing methods which should prevent the presence of microorganisms in food. An effective cleaning procedure may lead to a significant reduction (of up to 99.8%) of bacteria occurring on the food processing equipment (Dunsmore et al. 1981).
However, in this study, a relatively high number of the examined surfaces remained contaminated after sanitation. The hypothesis preceding initiation of this study was that antimicrobial susceptibility of S. aureus isolated from food contact surfaces. Surfaces that rely on food are extensively handled manually by person in-charge though there was tendered to any subsequent thermal or anti-microbial processing (cleaning process). Thus, there is a high potential for this kind of surface frequently contaminated with S. aureus since this bacteria are able to multiply on the skin and mucous membranes of the food handlers (Trabulsi & Alterthum, 2008).
This study showed that 14 out of 45 isolated samples were contaminated with S. aureus that has been confirmed by biochemical test result. Coagulase test is the only reliable method for identifying Staphylococcus aureus (Koneman et al., 1997). The production of coagulase can be confirmed by using either the slide coagulase test (SCT) or the tube coagulase test (TCT). Slide coagulase could spots bound of coagulase which also called as clumping factor (Koneman et al., 1997), that directly reacts with fibrinogen in plasma, caused the rapid cell agglutination. Negative isolates following SCT require confirmation with the superior TCT, since strains deficient in clumping factor usually produce free coagulase. Kawamura et al., stated that the tube coagulase would detects secreted extracellular free coagulase that reacts with a substance in plasma called “Coagulase-Reacting Factor” (CRF) to form a complex, which in turn reacts with fibrinogen to form fibrin by the clot. Strains of coagulase-positive staphylococci have been isolated from food contact surfaces and there are some staphylococcal isolates also ferment mannitol (Kawamura et al., 1998).
This study evaluated the performance of TCTs and MSA methods that commonly used in the identification of Staphylococcus aureus. The study from Kateete et al., (2010) evaluated the performance of common laboratory tests used regularly in the identification of Staphylococcus aureus infections in Uganda. The identification of clinical Staphylococcus aureus still mainly relies on the tube coagulase test, but it requires screening of the isolates with an additional test which is MSA prior to TCTs, for improved efficiency. There is no single phenotypic test that can assure reliable results in the identification of Staphylococcus aureus. The presence of S. aureus on food contact surfaces in this study indicate that there was improper handling or that equipment and surfaces were contaminated with biofilms formed by these bacteria.
Kroning et al., (2016) evaluated handmade sweets and Di Giannatale et al. (2011) evaluated different foods of animal origin, found that 12% and 14% of the samples was contaminated with S. aureus respectively. There is 66.6% of sweet isolates at the level of antimicrobial resistance. Both authors point out that proper hygiene of the food handlers, as well as correct cleaning of the food preparation surfaces, should decrease contamination by this microorganism, minimizing the risk of disease. Examining antimicrobial resistance, it was found that resistance to b-lactamics (penicillin and amoxicillin) predominated among the isolates, followed by quinolones (nalixidic acid). It is proved by Kroning et al., (2016) that evaluated the handmade sweets, got the high resistance for penicillin group. Some isolates were resistant to one antibiotic since the resistance toward penicillin and amoxicillin is the highest in S. aureus and can reach frequencies above 70% (Unakal and Kaliwal, 2010).
In this study, the level of resistance to these antimicrobials was 85.7% for penicillin G and 64.3% for amoxicillin. We observed that 21.4% of the isolates were multi-resistant to classes of Penicillin and quinolones. However, Kroning et al., (2016) evaluated the handmade sweets observed that 8.4% of the isolates were multi-resistant to erythromycin, tetracycline, ampicillin and penicillin. While, Tan et al. (2014) evaluated S. aureus isolated from the hands of handlers, and found resistance levels to ampicillin and penicillin, and a low multidrug resistance level (5.41%), similar to the one obtained in this study. Accordingly, the resistance levels found in this study can be explained by the indiscriminate use of antimicrobials in humans treating diseases, which is a worrying trend, as these isolates also have the ability to form biofilms. Under certain circumstances, such as the ones encountered during biofilm formation, the bacteria may encounter sub-lethal doses of drugs, so contributing to the emergence of resistant isolates.
This comprehensive study represents the largest one to date examining the prevalence of MRSA in food contact surface area. MRSA was found in 3 of 45 (6.7%) total isolates from food contact surfaces that collected from food premises around UPM. Most belonged to the chopping board and tray that was used during preparation of food. Pu et al., stated that the presence of MRSA in U.S. retail meats, first documented in Louisiana in 2009 since it has been reported in multiple regional surveys (Bhargava et al., 2011; Jackson et al., 2013; Molla et al., 2012). The overall prevalence was 0.1-6.6% and 0.3-7.0% in pork. MRSA was also present in 1.3-4.0% of beef collected (Bhargava et al., 2011; Jackson et al., 2013; Pu et al., 2009; Waters et al., 2011) but absent in others (Hanson et al., 2011; Kelman et al., 2011). Among studies that sampled poultry, MRSA was only detected in 3.9% of chicken and 1.7% of turkey in Michigan (Bhargava et al., 2011) and 4% of turkey in a five-city survey (Waters et al., 2011). Beilei et al., evaluated that the study sampled four types of meats (880 each) and MRSA was detected in turkey (3.5%), pork (1.9%), beef (1.7%), and chicken (0.3%), which fell within the ranges reported previously.
Aung et al., (2017) stated that, when antimcrobial agents were first being discovered it was thought that there would soon be an end to S. aureus infections. Unfortunately, that did not turn out to be the case. With each new antimicrobial agent discovered or developed, the bacteria found ways to fight each drug, either by mutation of its own genes, or by acquisition of genes from other bacteria. Now most S. aureus strains are resistant to the penicillin drugs and many are resistant to all b-lactam drugs. All strains of S. aureus have a huge arsenal of virulence factors, and now many are adding multidrug resistance as well (Aung et al., 2017). We cannot seem to develop new drugs fast enough to keep up with developing resistance. There were a few newer drugs that currently are fairly effective against S. aureus strains (ceftaroline, ceftobiprole, dalbavancin, iclaprim, tigecycline), and hoping that pharmaceutical researchers are able to develop drugs fast enough to keep S. aureus (especially MRSA strains) from becoming a major cause of mortality worldwide.
In conclusion, we reported three MRSA strains (SA002, SA006 and SA012) found from food contact surfaces at food premises around UPM. Humans themselves as a food handlers rather than animal were probably became the sources of contamination. Our limited findings suggest food contact surfaces as potential environmental sources for migration and spread of MRSA in the community. To date, little is known about the transmission of MRSA infections through food and food contact surfaces, however their possible roles in the distribution of specific MRSA lineages cannot be ruled out. The data warrant a more comprehensive and integrated (food premises approach) surveillance of MRSA in UPM area and elsewhere.