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The documented survival of pathogenic bacteria, including Listeria monocytogenes (LM), Shiga toxin–producing Escherichia coli (STEC), and Salmonella during the manufacture and aging of some cheeses highlights the need for additional interventions to enhance food safety. Unfortunately, few interventions are compliant with the Standards of Identity for cheese. Protective bacterial cultures (PCs) represent actionable, natural interventions. However, supportive data for commercially produced PCs regarding their efficacy against pathogens and potential antagonism with each other and cheesemaking cultures are scant, thereby impeding their potential use by the cheese industry. The overall objective of this study was to identify commercially produced PCs that exert antimicrobial activity toward pathogens with minimal impact on beneficial cheese microbes. Direct antagonism and agar well diffusion assays were used to determine the impact of 10 commercially produced PCs on the growth of starter cultures and cultures of ripening bacteria and fungi. Deferred antagonism was used to evaluate the potential for antimicrobial effects against LM, STEC, and Salmonella. PCs and starter cultures were cocultured in ultrahigh-temperature-processed milk to determine the effects of coculture on starter acidification profiles when incubated according to a simulated cheesemaking temperature profile (4 h at 35°C followed by 20 h at 20°C). Compatibility assays suggest that PC antagonism is microbe and strain specific. Only one PC negatively impacted the acidification of the starters tested. PC antagonism of ripening bacteria and fungi growth varied but was consistent within species. All PCs displayed deferred inhibition of LM, STEC, and Salmonella growth, but to varying degrees. These data identify commercial PCs with potential for the control of pathogens and characterize their compatibility with cheesemaking cultures for future use by cheesemakers and investigations of their efficacy in the production of cheese. HIGHLIGHTS

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Objective To determine whether bupivacaine liposomal injectable suspension (BLIS) supports microbial growth when artificially inoculated and to evaluate liposomal stability in the face of this extrinsic contamination as evidenced by changes in free bupivacaine concentrations. Study design A randomized, prospective in vitro study in which three vials of each BLIS, bupivacaine 0.5%, and propofol were individually inoculated with known concentrations of Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, and Candida albicans (n = 36) to quantify bacterial and fungal growth was conducted. Over 120 hours, aliquots from contaminated vials were withdrawn, plated, and incubated to determine microbial concentrations. High-pressure liquid chromatography (HPLC) was used to evaluate free bupivacaine concentrations over time in BLIS. Data were analyzed using a mixed effects model with multiple comparisons. Sample population Twelve vials of each BLIS, bupivacaine 0.5%, and propofol. Results BLIS did not support significant growth of Staphylococcus aureus or Candida albicans at any time. BLIS supported significant growth of Escherichia coli and Pseudomonas aeruginosa beginning at the 24 hour time point. Bupivacaine 0.5% did not support significant growth of any organisms. Propofol supported significant growth of all organisms. Free bupivacaine concentrations changed minimally over time. Conclusion Bacterial and fungal contaminant growth in artificially inoculated BLIS is organism dependent. BLIS supports significant growth of Escherichia coli and Pseudomonas aeruginosa. Extra-label handling of BLIS should only be undertaken with caution and with adherence to strict aseptic technique.